Materiały źródłowe

• #1 Chronic Sinusitis: Practice Essentials, Background, Anatomy

  https://emedicine.medscape.com/article/232791-overview

  Chronic sinusitis is an inflammatory process involving the paranasal sinus and persisting for at least 12 weeks. […] CRS may be noninfectious and associated with allergy, cystic fibrosis, gastroesophageal reflux, or exposure to environmental pollutants. Known risk factors include allergic rhinitis, nonallergic rhinitis, anatomic obstruction in the ostiomeatal complex, and immunologic disorders. […] Chronic sinusitis may be noninfectious and related to allergy, cystic fibrosis, gastroesophageal reflux, or exposure to environmental pollutants. […] The etiology of chronic sinusitis is multifactorial. The interaction between many systemic, local host, and environmental factors contribute to sinus inflammation and to the pathophysiology of the disease. Systemic factors include genetic diseases such as cystic fibrosis, conditions that cause immunodeficiency, autoimmune disease, idiopathic conditions such as Samter triad (aspirin-exacerbated respiratory disease), and acid reflux. Local host factors include sinonasal anatomic abnormalities, iatrogenic conditions such as scarring due to prior sinus surgery, neoplasm, or the presence of a foreign body, among others. Possible environmental factors that may contribute to the condition include the presence of biofilms and bacterial infection, as well as fungal infection, allergy, environmental pollutants, and smoking.

• #2 Chronic Rhinosinusitis | AAFP

  https://www.aafp.org/pubs/afp/issues/2017/1015/p500.html

  Chronic rhinosinusitis is an inflammatory disease of the paranasal sinuses that occurs in 1% to 5% of the U.S. population. […] Chronic rhinosinusitis is defined by the presence of at least two out of four cardinal symptoms (i.e., facial pain/pressure, hyposmia/anosmia, nasal drainage, and nasal obstruction) for at least 12 consecutive weeks, in addition to objective evidence. […] There is increasing evidence that chronic rhinosinusitis is an inflammatory disease and not an infectious process. […] Consistent with its underlying inflammatory etiologies, chronic rhinosinusitis is associated with other inflammatory diseases such as allergic rhinitis and asthma. […] Moreover, specific inflammatory and immunodeficiency conditions may rarely cause chronic rhinosinusitis, although symptoms that are not typical of chronic rhinosinusitis may also be present.

• #3 Chronic sinusitis: Symptoms, treatment, and causes

  https://www.medicalnewstoday.com/articles/320569

  Chronic sinusitis is sometimes called chronic rhinosinusitis. […] Treatment for chronic sinusitis depends on the underlying cause. […] The most common causes of chronic sinusitis include: A blockage that prevents the sinuses from draining: This can be due to damage to the nose or the face, nasal polyps and tumors, or because of a chronic infection. People with a deviated septum are more likely to develop chronic sinusitis. […] Exposure to irritants and allergens: People with allergies and asthma are more likely to develop chronic sinusitis because these conditions can increase pressure and irritation in the nasal passages and sinuses. […] Immune system problems: Diseases that weaken the immune system make it more difficult for the body to fight infections and inflammation. People with cystic fibrosis may be especially vulnerable to chronic sinusitis.

• #4 Chronic Rhinosinusitis | AAFP

  https://www.aafp.org/pubs/afp/issues/2017/1015/p500.html

  Chronic rhinosinusitis is an inflammatory disease of the paranasal sinuses that occurs in 1% to 5% of the U.S. population. […] Chronic rhinosinusitis is defined by the presence of at least two out of four cardinal symptoms (i.e., facial pain/pressure, hyposmia/anosmia, nasal drainage, and nasal obstruction) for at least 12 consecutive weeks, in addition to objective evidence. […] There is increasing evidence that chronic rhinosinusitis is an inflammatory disease and not an infectious process. […] Consistent with its underlying inflammatory etiologies, chronic rhinosinusitis is associated with other inflammatory diseases such as allergic rhinitis and asthma. […] Moreover, specific inflammatory and immunodeficiency conditions may rarely cause chronic rhinosinusitis, although symptoms that are not typical of chronic rhinosinusitis may also be present.

• #5 Chronic Rhinosinusitis—Microbiological Etiology, Potential Genetic Markers, and Diagnosis

  https://www.mdpi.com/1422-0067/25/6/3201

  Chronic rhinosinusitis (CRS) is a significant public health problem. Bacterial colonization and impaired mucociliary clearance play a significant role in the inflammatory process. Several inflammatory pathways and host defense elements are altered in CRS, which may contribute to observed differences in the microbiome. […] The literature data suggest that chronic inflammation may be caused by an abnormal immune response of the host mucosa rather than solely the presence of pathogens. In mucosal homeostasis, local irritants and pathogens are quickly and effectively eliminated through innate mucosal immune pathways without broader stimulation of the acquired immune system. The persistent inflammation seen in CRS may be due to a pathological imbalance in innate immune interactions between the host and the environment.

• #6 Chronic Rhinosinusitis | AAFP

  https://www.aafp.org/pubs/afp/issues/2017/1015/p500.html

  Chronic rhinosinusitis is an inflammatory disease of the paranasal sinuses that occurs in 1% to 5% of the U.S. population. […] Chronic rhinosinusitis is defined by the presence of at least two out of four cardinal symptoms (i.e., facial pain/pressure, hyposmia/anosmia, nasal drainage, and nasal obstruction) for at least 12 consecutive weeks, in addition to objective evidence. […] There is increasing evidence that chronic rhinosinusitis is an inflammatory disease and not an infectious process. […] Consistent with its underlying inflammatory etiologies, chronic rhinosinusitis is associated with other inflammatory diseases such as allergic rhinitis and asthma. […] Moreover, specific inflammatory and immunodeficiency conditions may rarely cause chronic rhinosinusitis, although symptoms that are not typical of chronic rhinosinusitis may also be present.

• #7 Patient education: Chronic rhinosinusitis (Beyond the Basics) – UpToDate

  https://www.uptodate.com/contents/chronic-rhinosinusitis-beyond-the-basics/print

  Chronic rhinosinusitis often has more complicated and elusive causes. […] Infections can certainly contribute to or worsen chronic rhinosinusitis, but people with the chronic condition usually have longstanding inflammation that cannot be explained by infection alone. […] Chronic rhinosinusitis without nasal polyposis is the most common type of rhinosinusitis. In this form of rhinosinusitis, the swelling and irritation of the sinus lining may be caused by different factors, such as allergies to things in the air, irritation from things in the air, and infections. […] Some people with chronic rhinosinusitis have abnormal growth of tissue inside their noses or sinuses called „nasal polyps.” […] Some people with chronic rhinosinusitis develop a strong inflammatory response to fungi inside their sinuses.

• #8 Chronic Sinusitis: Practice Essentials, Background, Anatomy

  https://emedicine.medscape.com/article/232791-overview

  Chronic sinusitis is an inflammatory process involving the paranasal sinus and persisting for at least 12 weeks. […] CRS may be noninfectious and associated with allergy, cystic fibrosis, gastroesophageal reflux, or exposure to environmental pollutants. Known risk factors include allergic rhinitis, nonallergic rhinitis, anatomic obstruction in the ostiomeatal complex, and immunologic disorders. […] Chronic sinusitis may be noninfectious and related to allergy, cystic fibrosis, gastroesophageal reflux, or exposure to environmental pollutants. […] The etiology of chronic sinusitis is multifactorial. The interaction between many systemic, local host, and environmental factors contribute to sinus inflammation and to the pathophysiology of the disease. Systemic factors include genetic diseases such as cystic fibrosis, conditions that cause immunodeficiency, autoimmune disease, idiopathic conditions such as Samter triad (aspirin-exacerbated respiratory disease), and acid reflux. Local host factors include sinonasal anatomic abnormalities, iatrogenic conditions such as scarring due to prior sinus surgery, neoplasm, or the presence of a foreign body, among others. Possible environmental factors that may contribute to the condition include the presence of biofilms and bacterial infection, as well as fungal infection, allergy, environmental pollutants, and smoking.

• #9 Chronic sinusitis – Symptoms and causes – Mayo Clinic

  https://www.mayoclinic.org/diseases-conditions/chronic-sinusitis/symptoms-causes/syc-20351661

  An infection, growths in the sinuses, called nasal polyps, or swelling of the lining of the sinuses can cause chronic sinusitis. […] The cause of chronic sinusitis usually is not known. Some medical conditions, including cystic fibrosis, can cause chronic sinusitis in children and teens. […] Some conditions can make chronic sinusitis worse. These include: A common cold or other infection that affects the sinuses. Viruses or bacteria can cause these infections. […] A problem inside the nose, such as a deviated nasal septum, nasal polyps or tumors.

• #10 Chronic sinusitis: Causes, symptoms and how to treat it | HealthPartners Blog

  https://www.healthpartners.com/blog/chronic-sinusitis-symptoms/

  For some people, these symptoms may be signs of chronic sinusitis, a condition that can be caused by infection, inflammation, growths or the shape of your nasal passages. […] There are many specific causes of chronic sinusitis, but they can be grouped into three main categories: infection, inflammation and the shape of the passages inside your nose. […] Chronic sinus infections are one of the most common causes of chronic sinusitis and can be caused by an untreated bacterial or fungal infection in the nasal passages. However, chronic sinusitis can also be caused by other infections in your face such as an infected tooth. […] If you have ongoing inflammation in your sinuses, it can make it hard for you your nasal passages to drain, leading to a buildup of mucus in your sinuses. Possible reasons for lasting inflammation include:

• #11 Chronic Sinusitis: Treatment, Symptoms, and Causes

  https://www.healthline.com/health/chronic-sinusitis

  With chronic sinusitis, the tissues inside your sinuses become inflamed and blocked for a long period of time due to swelling and mucus buildup. […] Chronic sinusitis can have many other causes. […] Following are the most common causes of chronic sinusitis: Allergies, especially hay fever or environmental allergies (such as to pollen or chemicals). These can cause your nasal passages to become inflamed. […] Tissue growths known as polyps inside your nose. Nasal polyps can make it hard to breathe through your nose and block your sinuses. […] An uneven wall of tissue between your nostrils. This is known as a deviated septum, and it can limit air flow in one or both of your nostrils. […] Infections in your nose, windpipe, or lungs by viruses or bacteria (including colds). These are called respiratory tract infections. They can cause your nose to become inflamed and make it hard for mucus to drain out of your nose.

• #12 Chronic Sinusitis: Causes, Symptoms, and Treatment

  https://patient.info/ears-nose-throat-mouth/acute-sinusitis/chronic-sinusitis

  Breathing in pollutants and other irritants, such as pesticides, dust, cleaning agents, and toxic gases can also cause inflammation in the nose and sinuses, leading to chronic sinusitis. […] Allergies are more common in people with chronic sinusitis. Allergies, such as to dust mites, animal fur, and mould, can cause chronic rhinitis, and may make chronic sinusitis symptoms worse. […] It’s possible that overgrowth or imbalance in fungi growth might contribute to chronic sinusitis, although this is probably only a factor in a small number of cases. […] Sometimes, changes in the shape of the nasal passages and the sinuses can cause narrowings, and prevent nasal mucus from draining properly. This can contribute to chronic sinusitis. […] Dental problems can cause maxillary sinusitis, such as gum disease, dental infections, including deep infections or abscesses, and complications from dental procedures.

• #13 Sinus Infection (Sinusitis): Causes, Symptoms & Treatment

  https://my.clevelandclinic.org/health/diseases/17701-sinusitis

  Sinusitis is usually caused by the common cold, but other viruses, bacteria, fungi and allergies can also cause sinusitis. […] Chronic sinusitis symptoms last at least 12 weeks. Bacteria are usually the cause. […] Viruses, bacteria, fungi and allergens can cause sinusitis. Specific triggers for sinusitis include: The common cold, The flu (influenza), Streptococcus pneumoniae bacteria, Haemophilus influenza bacteria, Moraxella catarrhalis bacteria, Nasal and seasonal allergies. […] Some people are more likely to get sinusitis than others. Risk factors include: Nasal allergies, Asthma, Nasal polyps (growths), Deviated septum, A weakened immune system, Smoking. […] Sinus infections are common and usually not serious. They can have many causes, including viruses and bacteria, nasal polyps or allergies.

• #14 Chronic sinusitis: Symptoms, treatment, and causes

  https://www.medicalnewstoday.com/articles/320569

  Chronic sinusitis is sometimes called chronic rhinosinusitis. […] Treatment for chronic sinusitis depends on the underlying cause. […] The most common causes of chronic sinusitis include: A blockage that prevents the sinuses from draining: This can be due to damage to the nose or the face, nasal polyps and tumors, or because of a chronic infection. People with a deviated septum are more likely to develop chronic sinusitis. […] Exposure to irritants and allergens: People with allergies and asthma are more likely to develop chronic sinusitis because these conditions can increase pressure and irritation in the nasal passages and sinuses. […] Immune system problems: Diseases that weaken the immune system make it more difficult for the body to fight infections and inflammation. People with cystic fibrosis may be especially vulnerable to chronic sinusitis.

• #15 Causes of Rhinosinusitis

  https://www.clinicbarcelona.org/en/assistance/diseases/rhinosinusitis/causes-and-risk-factors

  It is unclear what role microorganisms play in the development of chronic rhinosinusitis. […] Chronic alteration to mucociliary transport is characterised by cough, rhinitis and chronic sinusitis due to abnormal ciliary function in the respiratory tract. […] Mucus with altered characteristics occurs in cases of cystic fibrosis. […] Asthma shares a close association with chronic rhinosinusitis. […] Sensitivity to non-steroidal anti-inflammatories can trigger a chronic inflammation of the lower and upper airway (paranasal sinuses). […] Immune system disorders, such as HIV or common variable immunodeficiency, can also be a factor. […] Allergic rhinitis causes swelling in the nasal mucosa that can partially block the drainage holes from the paranasal sinuses. […] Environmental factors, such as regular exposure to contaminants like tobacco smoke, may contribute. […] Anatomical variations, such as septal deviation, alterations to the uncinate process or concha bullosa, can also play a role.

• #16 Chronic Rhinosinusitis

  https://med.uth.edu/orl/texas-sinus-institute/patient-education/chronic-rhinosinusitis/

  Mucociliary Dysfunction Under normal circumstances, the lining of the sinuses is covered by a think blanket of mucus, which is propelled in a programmed fashion by cilia on the surface of the sinus lining. These cilia act as oars to move the mucus. Disruption of this activity leads to stagnation of the mucus, and eventually infection and CRS. […] OMC Compromise The ostiomeatal complex region is the common outflow channel for the anterior ethmoid, frontal and maxillary sinuses. Blockage of the OMC causes blockage of the upstream sinuses and CRS. […] Staphylococcal Superantigen Certain species of Staphylococcus can secrete substances (known as exotoxins) that can directly stimulate the immune system to produce a strong inflammatory reaction and CRS. […] Miscellaneous ASA triad (also known as Sampters triad) is characterized by nasal polyps, asthma, and aspirin intolerance. In these patients, aspirin produces a skin reaction, asthma, and even a severe reaction that can be life threatening. […] Churg-Straus Syndrome (also known as granulomatous vasculitis) results from a inflammation of blood vessels. Patients with this condition have severe asthma, sinusitis, and other related illnesses.

• #17 Most Common Causes Of Chronic Sinusitis And Its Treatment Options

  https://www.socalsinus.com/causes-of-chronic-sinusitis/

  Chronic sinusitis develops when the passages and sinus cavities are unable to drain mucus efficiently due to blockage, inflammation, or a buildup of mucus, germs, and bacteria. […] Nasal polyps, septum deviations, hypertrophic turbinates, and other tissue abnormalities that alter and block the sinuses and nasal airways are generally the most common reason some people develop chronic sinusitis. […] Chronic sinusitis is highly prevalent in individuals with a history of facial trauma, weak immunity, septum deviations, allergies, nasal polyps, and other health concerns.

• #18 Most Common Causes of Chronic Sinusitis You Should Be Aware Of

  https://www.828urgentcare.com/blog/most-common-causes-of-chronic-sinusitis-you-should-be-aware-of

  Nose injury: A deviated septum may also happen due to a nose injury that can cause the nasal septum to move out of its original position. […] Other medical conditions: Complications occurring due to immune system-related diseases like HIV and cystic fibrosis can lead to nasal blockage. […] The aging process may also affect the nasal structures that can worsen a deviated septum in the long run. Furthermore, irritation and swelling of the sinus or nasal cavities caused by an infection may narrow the nasal passage further, resulting in nasal obstruction.

• #19 5 of The Most Common Causes of Sinusitis

  https://www.socalsinus.com/5-of-the-most-common-causes-of-sinusitis/

  Chronic sinusitis, also known as recurrent acute rhinosinusitis, is similar to acute sinus infections, but the primary difference is symptoms occur more frequently or worsen before going away after 10 to 12 weeks or recur at least three times within a rolling 12-month period. […] Many people prone to sinus infections have allergies and are sensitive to substances and particles in the air they breathe. […] Sinusitis that occurs from structural septum abnormalities don’t normally respond to conventional therapeutics and remedies. […] Nasal polyps are small, abnormal growths that develop in the sinuses or nose. […] Enlarged turbinates are a common cause of sinus infections and nasal congestion that can lead to headaches, facial pain, trouble sleeping, eating, smelling, and additional discomfort. […] Many people who experience severe or persistent nasal congestion develop persistent and severely debilitating sinus infection symptoms that require medical attention for relief.

• #20 The Etiology and Pathogenesis of Chronic Rhinosinusitis: a Review of Current Hypotheses

  https://pmc.ncbi.nlm.nih.gov/articles/PMC4874491/

  The etiology and pathogenesis of CRS remain an active area of research. Fungi and bacteria have been implicated as important environmental factors contributing to chronic mucosal inflammation and have thus formed the basis of the fungal hypothesis, the superantigen hypothesis, the biofilm hypothesis, and the microbiome hypothesis. Increasing evidence, however, shows that these exogenous agents are unable to explain the full gamut of clinical variants, inflammatory profiles, and histologic patterns of CRS. Fungi and bacteria are thus generally viewed as disease modifiers of CRS, which accentuate, rather than cause, a dysfunctional immune response in CRS hosts. The eicosanoid hypothesis and the immune barrier hypothesis, in contrast, highlight the contribution of host variables in CRS pathogenesis. The immune barrier hypothesis specifically emphasizes the likely role of genetics and epigenetics in the development of functional deficits at the level of the sinonasal epithelium. These defects ultimately result in a dysfunctional inflammatory response when triggered by external stimuli, with some supporting data provided by the environmentally based hypotheses.

• #21 Chronic Sinusitis: Causes, Symptoms, and Treatment

  https://patient.info/ears-nose-throat-mouth/acute-sinusitis/chronic-sinusitis

  Chronic sinusitis has a complicated set of causes. The main problem in chronic sinusitis is inflammation in the sinuses, and this can be caused by lots of things. The cause of chronic sinusitis differs from person to person, and there may be more than one cause present. […] It’s thought that certain viral infections could be the initial trigger for chronic sinusitis, perhaps by starting a process of inflammation that never fully resolves even after the virus has gone. Viral infections can also cause symptom flare-ups in people with chronic sinusitis. […] There might also be a link with bacterial infections, although this is complex, controversial, and not fully understood. It’s possible that chronic (long-lasting) bacterial infection may cause some cases of chronic sinusitis. […] Smoking is a strong risk factor for chronic sinusitis. Cigarette smoke damages the lining of the nose and sinuses, causing inflammation. It also leads to increased mucus production.

• #22 Chronic Sinusitis – StatPearls – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK441934/

  Chronic sinusitis is multifactorial in nature and can include infectious, inflammatory, or structural factors. […] Other etiologies such as allergic rhinitis (dust mites, molds), exposures (airborne irritants, cigarette smoke or other toxins), structural causes (nasal polyps, deviated nasal septum), ciliary dysfunction, immunodeficiencies, and fungal infections should be considered. […] As stated in the acute sinusitis chapter, viruses and bacteria are the most common etiologies for sinusitis. Streptococcus, pneumococcus, Hemophilus, and Moraxella are the most common bacterial causes.

• #23 Sinus Infection (Sinusitis): Causes, Symptoms & Treatment

  https://my.clevelandclinic.org/health/diseases/17701-sinusitis

  Sinusitis is usually caused by the common cold, but other viruses, bacteria, fungi and allergies can also cause sinusitis. […] Chronic sinusitis symptoms last at least 12 weeks. Bacteria are usually the cause. […] Viruses, bacteria, fungi and allergens can cause sinusitis. Specific triggers for sinusitis include: The common cold, The flu (influenza), Streptococcus pneumoniae bacteria, Haemophilus influenza bacteria, Moraxella catarrhalis bacteria, Nasal and seasonal allergies. […] Some people are more likely to get sinusitis than others. Risk factors include: Nasal allergies, Asthma, Nasal polyps (growths), Deviated septum, A weakened immune system, Smoking. […] Sinus infections are common and usually not serious. They can have many causes, including viruses and bacteria, nasal polyps or allergies.

• #24 Chronic Sinusitis: Practice Essentials, Background, Anatomy

  https://emedicine.medscape.com/article/232791-overview

  Increasing evidence shows that biofilms are critical to the pathophysiology of chronic infections including chronic sinusitis. […] Currently, etiologic studies of sinusitis are increasingly focusing on ostiomeatal obstruction, allergies, polyps, occult and subtle immunodeficiency states, and dental diseases. Microorganisms are more often recognized as secondary invaders. Any disease process or toxin that affects cilia has a negative effect on CRS.

• #25 Chronic Rhinosinusitis

  https://med.uth.edu/orl/texas-sinus-institute/patient-education/chronic-rhinosinusitis/

  Biofilms Biofilms are complex, three-dimensional structures of living bacteria. They have been identified in approximately 2533% of patients with CRS in some studies. […] Fungal Infection Cultures of sinus secretions from patients with CRS have grown fungus. Furthermore, it has been shown that the immune system of patients with CRS have a greater response when exposed to fungal proteins at least in the laboratory. […] Genetic Disorders Patients with cystic fibrosis (CF), a hereditary condition that effects mostly the lungs, also develop significant CRS. CF and other genetic diseases may be causes of CRS. […] Osteitis The bone in the walls of the sinuses of patients with severe CRS undergoes a remodeling process that produces thicker, but abnormal bone. This finding, known as osteitis, suggests that changes in the bone may contribute to CRS.

• #26 „What Causes Chronic Sinusitis?”Visit Sinus Service – Southwest Ohio ENT Specialists

  https://soents.com/what-causes-chronic-sinusitis/

  Chronic Rhinosinusitis (CRS) is a complex group of conditions that cause persistent inflammation of the nasal sinuses. […] It is important to remember that CRS does not have a single cause, but multiple causes. Each patients case is unique. […] In studies of US patients with chronic sinusitis, non eosinophilic sinusitis is the most common subtype. This form of sinusitis most likely arises from an underlying anatomic obstruction of the nasal sinuses, which prevents proper mucous drainage and airflow. This leads to chronic inflammation and makes patients prone to recurrent infections. […] An alternative cause may be from the formation of bacterial biofilms which can cause bacterial sinus infections that do not clear with oral antibiotics. […] This more severe form of sinusitis is typically found in patients with Asthma or other chronic inflammatory conditions that cause an increased number of eosinophils (a type of inflammatory white blood cell) to be present in sinus tissues.

• #27 Chronic Rhinosinusitis

  https://med.uth.edu/orl/texas-sinus-institute/patient-education/chronic-rhinosinusitis/

  Mucociliary Dysfunction Under normal circumstances, the lining of the sinuses is covered by a think blanket of mucus, which is propelled in a programmed fashion by cilia on the surface of the sinus lining. These cilia act as oars to move the mucus. Disruption of this activity leads to stagnation of the mucus, and eventually infection and CRS. […] OMC Compromise The ostiomeatal complex region is the common outflow channel for the anterior ethmoid, frontal and maxillary sinuses. Blockage of the OMC causes blockage of the upstream sinuses and CRS. […] Staphylococcal Superantigen Certain species of Staphylococcus can secrete substances (known as exotoxins) that can directly stimulate the immune system to produce a strong inflammatory reaction and CRS. […] Miscellaneous ASA triad (also known as Sampters triad) is characterized by nasal polyps, asthma, and aspirin intolerance. In these patients, aspirin produces a skin reaction, asthma, and even a severe reaction that can be life threatening. […] Churg-Straus Syndrome (also known as granulomatous vasculitis) results from a inflammation of blood vessels. Patients with this condition have severe asthma, sinusitis, and other related illnesses.

• #28 The Etiology and Pathogenesis of Chronic Rhinosinusitis: a Review of Current Hypotheses

  https://pmc.ncbi.nlm.nih.gov/articles/PMC4874491/

  While the relative importance of each factor remains a matter of debate, there is an emerging consensus on two points: (1) specific factors likely vary in importance in individual patients and (2) CRS is an antegrade process in that the mucosal inflammation is most commonly triggered by exogenous agents inhaled through the nose. Overall, this leads to the concept that CRS is most inclusively described as a dysfunctional interaction that occurs at the site of interface between the host and the environment—the sinonasal mucosa. […] Overall, six broad hypotheses on CRS etiology and pathogenesis have thus far been proposed, each describing a central role for one or more aspects of these factors: (1) the fungal hypothesis, (2) the superantigen hypothesis, (3) the biofilm hypothesis, and (4) the microbiome hypothesis, all of which emphasize key environmental factors, and (5) the eicosanoid hypothesis and (6) the immune barrier hypothesis, which focus on host factors.

• #29 Chronic Sinusitis: Causes, Symptoms, and Treatment

  https://patient.info/ears-nose-throat-mouth/acute-sinusitis/chronic-sinusitis

  Chronic sinusitis has a complicated set of causes. The main problem in chronic sinusitis is inflammation in the sinuses, and this can be caused by lots of things. The cause of chronic sinusitis differs from person to person, and there may be more than one cause present. […] It’s thought that certain viral infections could be the initial trigger for chronic sinusitis, perhaps by starting a process of inflammation that never fully resolves even after the virus has gone. Viral infections can also cause symptom flare-ups in people with chronic sinusitis. […] There might also be a link with bacterial infections, although this is complex, controversial, and not fully understood. It’s possible that chronic (long-lasting) bacterial infection may cause some cases of chronic sinusitis. […] Smoking is a strong risk factor for chronic sinusitis. Cigarette smoke damages the lining of the nose and sinuses, causing inflammation. It also leads to increased mucus production.

• #30 Chronic Sinusitis: Causes, Symptoms, and Treatment

  https://patient.info/ears-nose-throat-mouth/acute-sinusitis/chronic-sinusitis

  Chronic sinusitis has a complicated set of causes. The main problem in chronic sinusitis is inflammation in the sinuses, and this can be caused by lots of things. The cause of chronic sinusitis differs from person to person, and there may be more than one cause present. […] It’s thought that certain viral infections could be the initial trigger for chronic sinusitis, perhaps by starting a process of inflammation that never fully resolves even after the virus has gone. Viral infections can also cause symptom flare-ups in people with chronic sinusitis. […] There might also be a link with bacterial infections, although this is complex, controversial, and not fully understood. It’s possible that chronic (long-lasting) bacterial infection may cause some cases of chronic sinusitis. […] Smoking is a strong risk factor for chronic sinusitis. Cigarette smoke damages the lining of the nose and sinuses, causing inflammation. It also leads to increased mucus production.

• #31 Chronic Rhinosinusitis, Nasal Polyps – Melbourne ENT Group

  https://melbentgroup.com.au/chronic-rhinosinusitis-crs/

  Chronic rhinosinusitis often has more complicated and elusive causes. […] Infections can certainly contribute to or worsen chronic rhinosinusitis, but people with the chronic condition usually have longstanding inflammation that cannot be explained by infection alone. […] In this form of rhinosinusitis, the swelling and irritation of the sinus lining may be caused by different factors, such as allergies to things in the air, irritation from things in the air, and infections. […] Some people with chronic rhinosinusitis develop a strong allergic response to fungi inside their sinuses. […] Allergies are much more common among people with chronic rhinosinusitis than they are among people in the general population. […] Exposure to cigarette smoke or certain environmental toxins, such as formaldehyde, can increase the risk of chronic rhinosinusitis. […] Some people develop chronic rhinosinusitis after having repeated viral infections, although it is not clear that the infections actually cause the chronic rhinosinusitis. […] A deviated septum may cause one nostril to be blocked, but it usually does not cause chronic rhinosinusitis.

• #32 Chronic Rhinosinusitis

  https://med.uth.edu/orl/texas-sinus-institute/patient-education/chronic-rhinosinusitis/

  Biofilms Biofilms are complex, three-dimensional structures of living bacteria. They have been identified in approximately 2533% of patients with CRS in some studies. […] Fungal Infection Cultures of sinus secretions from patients with CRS have grown fungus. Furthermore, it has been shown that the immune system of patients with CRS have a greater response when exposed to fungal proteins at least in the laboratory. […] Genetic Disorders Patients with cystic fibrosis (CF), a hereditary condition that effects mostly the lungs, also develop significant CRS. CF and other genetic diseases may be causes of CRS. […] Osteitis The bone in the walls of the sinuses of patients with severe CRS undergoes a remodeling process that produces thicker, but abnormal bone. This finding, known as osteitis, suggests that changes in the bone may contribute to CRS.

• #33 Sinusitis – Ear, Nose, and Throat Disorders – Merck Manual Professional Edition

  https://www.merckmanuals.com/professional/ear-nose-and-throat-disorders/nose-and-paranasal-sinus-disorders/sinusitis

  Chronic sinusitis involves many factors that combine to create chronic inflammation. Chronic allergies, structural abnormalities (eg, nasal polyps), environmental irritants (eg, airborne pollution, tobacco smoke), mucociliary dysfunction, and other factors interact with infectious organisms to cause chronic sinusitis. The organisms are commonly bacterial (possibly as part of a biofilm on the mucosal surface) but may be fungal. Many bacteria have been implicated, including gram-negative bacilli and oropharyngeal anaerobic microorganisms; polymicrobial infection is common. In a few cases, chronic maxillary sinusitis is secondary to dental infection. Fungal infections (Aspergillus, Sporothrix, Pseudallescheria) may be chronic and tend to strike older and immunocompromised patients. […] Allergic fungal sinusitis is a form of chronic sinusitis characterized by diffuse nasal congestion, markedly viscid nasal secretions, and, often, nasal polyps. It is an allergic response to the presence of topical fungi, often Aspergillus, and is not caused by an invasive infection. […] Invasive fungal sinusitis is an aggressive, sometimes fatal, infection in immunocompromised patients, usually caused by Aspergillus or Mucor species.

• #34 Sinusitis – Ear, Nose, and Throat Disorders – Merck Manual Professional Edition

  https://www.merckmanuals.com/professional/ear-nose-and-throat-disorders/nose-and-paranasal-sinus-disorders/sinusitis

  Chronic sinusitis involves many factors that combine to create chronic inflammation. Chronic allergies, structural abnormalities (eg, nasal polyps), environmental irritants (eg, airborne pollution, tobacco smoke), mucociliary dysfunction, and other factors interact with infectious organisms to cause chronic sinusitis. The organisms are commonly bacterial (possibly as part of a biofilm on the mucosal surface) but may be fungal. Many bacteria have been implicated, including gram-negative bacilli and oropharyngeal anaerobic microorganisms; polymicrobial infection is common. In a few cases, chronic maxillary sinusitis is secondary to dental infection. Fungal infections (Aspergillus, Sporothrix, Pseudallescheria) may be chronic and tend to strike older and immunocompromised patients. […] Allergic fungal sinusitis is a form of chronic sinusitis characterized by diffuse nasal congestion, markedly viscid nasal secretions, and, often, nasal polyps. It is an allergic response to the presence of topical fungi, often Aspergillus, and is not caused by an invasive infection. […] Invasive fungal sinusitis is an aggressive, sometimes fatal, infection in immunocompromised patients, usually caused by Aspergillus or Mucor species.

• #35 Patient education: Chronic rhinosinusitis (Beyond the Basics) – UpToDate

  https://www.uptodate.com/contents/chronic-rhinosinusitis-beyond-the-basics

  Some people with chronic rhinosinusitis develop a strong inflammatory response to fungi inside their sinuses. It is normal for air to contain small amounts of fungi, and most people can breathe in air containing fungal spores without problems. However, in some people, the allergy to fungi causes the sinus lining to make thick, dense mucus that fills the sinuses.

• #36 Sinusitis – Ear, Nose, and Throat Disorders – Merck Manual Professional Edition

  https://www.merckmanuals.com/professional/ear-nose-and-throat-disorders/nose-and-paranasal-sinus-disorders/sinusitis

  Chronic sinusitis involves many factors that combine to create chronic inflammation. Chronic allergies, structural abnormalities (eg, nasal polyps), environmental irritants (eg, airborne pollution, tobacco smoke), mucociliary dysfunction, and other factors interact with infectious organisms to cause chronic sinusitis. The organisms are commonly bacterial (possibly as part of a biofilm on the mucosal surface) but may be fungal. Many bacteria have been implicated, including gram-negative bacilli and oropharyngeal anaerobic microorganisms; polymicrobial infection is common. In a few cases, chronic maxillary sinusitis is secondary to dental infection. Fungal infections (Aspergillus, Sporothrix, Pseudallescheria) may be chronic and tend to strike older and immunocompromised patients. […] Allergic fungal sinusitis is a form of chronic sinusitis characterized by diffuse nasal congestion, markedly viscid nasal secretions, and, often, nasal polyps. It is an allergic response to the presence of topical fungi, often Aspergillus, and is not caused by an invasive infection. […] Invasive fungal sinusitis is an aggressive, sometimes fatal, infection in immunocompromised patients, usually caused by Aspergillus or Mucor species.

• #37 Chronic Sinusitis: Causes, Symptoms, and Treatment

  https://patient.info/ears-nose-throat-mouth/acute-sinusitis/chronic-sinusitis

  Breathing in pollutants and other irritants, such as pesticides, dust, cleaning agents, and toxic gases can also cause inflammation in the nose and sinuses, leading to chronic sinusitis. […] Allergies are more common in people with chronic sinusitis. Allergies, such as to dust mites, animal fur, and mould, can cause chronic rhinitis, and may make chronic sinusitis symptoms worse. […] It’s possible that overgrowth or imbalance in fungi growth might contribute to chronic sinusitis, although this is probably only a factor in a small number of cases. […] Sometimes, changes in the shape of the nasal passages and the sinuses can cause narrowings, and prevent nasal mucus from draining properly. This can contribute to chronic sinusitis. […] Dental problems can cause maxillary sinusitis, such as gum disease, dental infections, including deep infections or abscesses, and complications from dental procedures.

• #38 The Etiology and Pathogenesis of Chronic Rhinosinusitis: a Review of Current Hypotheses

  https://pmc.ncbi.nlm.nih.gov/articles/PMC4874491/

  Chronic rhinosinusitis (CRS) is a broad clinical syndrome that is characterized by prolonged mucosal inflammation of the nose and paranasal sinuses, and is typically divided into two subtypes based on the presence or absence of nasal polyps. The etiology and pathogenesis of both forms remain areas of active research. Over the last 15 years, a number of hypotheses have been proposed to explain all or part of the clinical CRS spectrum. These hypotheses reflect the concept that CRS results from a dysfunctional interplay between individual host characteristics and factors exogenous to the host. Six broad theories on CRS etiology and pathogenesis are discussed as follows: (1) the fungal hypothesis, (2) the superantigen hypothesis, (3) the biofilm hypothesis, and (4) the microbiome hypothesis, all of which emphasize key environmental factors, and (5) the eicosanoid hypothesis and (6) the immune barrier hypothesis, which describe specific host factors. These theories are reviewed, and the evidence supporting them is critically appraised.

• #39 Chronic Rhinosinusitis, Nasal Polyps – Melbourne ENT Group

  https://melbentgroup.com.au/chronic-rhinosinusitis-crs/

  Chronic rhinosinusitis often has more complicated and elusive causes. […] Infections can certainly contribute to or worsen chronic rhinosinusitis, but people with the chronic condition usually have longstanding inflammation that cannot be explained by infection alone. […] In this form of rhinosinusitis, the swelling and irritation of the sinus lining may be caused by different factors, such as allergies to things in the air, irritation from things in the air, and infections. […] Some people with chronic rhinosinusitis develop a strong allergic response to fungi inside their sinuses. […] Allergies are much more common among people with chronic rhinosinusitis than they are among people in the general population. […] Exposure to cigarette smoke or certain environmental toxins, such as formaldehyde, can increase the risk of chronic rhinosinusitis. […] Some people develop chronic rhinosinusitis after having repeated viral infections, although it is not clear that the infections actually cause the chronic rhinosinusitis. […] A deviated septum may cause one nostril to be blocked, but it usually does not cause chronic rhinosinusitis.

• #40 Patient education: Chronic rhinosinusitis (Beyond the Basics) – UpToDate

  https://www.uptodate.com/contents/chronic-rhinosinusitis-beyond-the-basics/print

  Several factors can increase your risk of chronic rhinosinusitis or worsen your symptoms once you have the disorder. […] Some people develop chronic rhinosinusitis after having repeated viral infections. […] Allergies are more common among people with chronic rhinosinusitis than they are among people in the general population. […] Exposure to cigarette smoke or certain environmental irritants can increase the risk of chronic rhinosinusitis. […] Most people with chronic rhinosinusitis have normal immune systems. However, people with certain immune system problems are at an increased risk of chronic rhinosinusitis. […] A deviated septum is a common cause of nasal blockage. It may cause one nostril or sometimes both nostrils to be blocked, but it is not a common cause of chronic rhinosinusitis.

• #41 Chronic Sinusitis (in Adults) – Harvard Health

  https://www.health.harvard.edu/a_to_z/chronic-sinusitis-in-adults-a-to-z

  Chronic sinusitis is a long-term inflammation of the sinuses. […] Anything that obstructs that flow can cause a buildup of mucus, and sometimes pus, in the sinuses. Drainage from the sinuses can be obstructed by structural abnormalities of the nose, infection, or tissue swelling caused by allergies. […] In adults, chronic sinusitis most often is linked to nasal swelling caused by allergies, especially allergies to inhaled dust, mold, pollen, or the spores of fungi. […] Polyps, nasal tumors and nasal fractures can obstruct the sinus drainage leading to chronic sinusitis. Chronic sinusitis also can be seen in people whose sinuses and nasal passages are structurally abnormally narrow. People with asthma, cystic fibrosis, or immune system problems develop chronic sinusitis more often than others.

• #42 Chronic Sinusitis: Causes, Symptoms, and Treatment

  https://patient.info/ears-nose-throat-mouth/acute-sinusitis/chronic-sinusitis

  Breathing in pollutants and other irritants, such as pesticides, dust, cleaning agents, and toxic gases can also cause inflammation in the nose and sinuses, leading to chronic sinusitis. […] Allergies are more common in people with chronic sinusitis. Allergies, such as to dust mites, animal fur, and mould, can cause chronic rhinitis, and may make chronic sinusitis symptoms worse. […] It’s possible that overgrowth or imbalance in fungi growth might contribute to chronic sinusitis, although this is probably only a factor in a small number of cases. […] Sometimes, changes in the shape of the nasal passages and the sinuses can cause narrowings, and prevent nasal mucus from draining properly. This can contribute to chronic sinusitis. […] Dental problems can cause maxillary sinusitis, such as gum disease, dental infections, including deep infections or abscesses, and complications from dental procedures.

• #43 Understanding Chronic Sinusitis: Symptoms, Causes, and Diagnosis – Kamelhar

  https://kamelharpulmonary.com/understanding-chronic-sinusitis-symptoms-causes-and-diagnosis/

  There is a strong connection between asthma and chronic sinusitis. Both conditions involve inflammation of the airways, and they often coexist. Individuals with asthma are more susceptible to developing chronic sinusitis, and vice versa. […] Certain immune system disorders can weaken the body’s ability to fight off infections, increasing the risk of chronic sinusitis. Conditions such as cystic fibrosis, HIV, and immune deficiencies can impair the immune response and make individuals more vulnerable to sinus infections. […] Exposure to irritants in the environment can contribute to chronic sinusitis. These irritants include tobacco smoke, air pollution, chemical fumes, and strong odors. Regular exposure can irritate the sinus lining, leading to inflammation and persistent symptoms. […] Family history plays a role in the development of chronic sinusitis. If you have close relatives with a history of chronic sinusitis or allergies, you may be at an increased risk of developing the condition. Genetic factors can influence the structure of the sinuses, immune response, and susceptibility to allergies.

• #44 Sinusitis – Wikipedia

  https://en.wikipedia.org/wiki/Sinusitis

  Sinusitis is a condition that affects both children and adults. It is caused by a combination of environmental and a person’s individual health factors. […] Most cases are caused by a viral infection. […] Chronic sinusitis lasts longer than 12 weeks and can be caused by many different diseases that share chronic inflammation of the sinuses as a common symptom. […] It may develop with anatomic derangements, including deviation of the nasal septum and the presence of concha bullosa (pneumatization of the middle concha) that inhibit the outflow of mucus, or with allergic rhinitis, asthma, cystic fibrosis, and dental infections. […] Chronic rhinosinusitis represents a multifactorial inflammatory disorder, rather than simply a persistent bacterial infection. […] Recent theories of sinusitis indicate that it often occurs as part of a spectrum of diseases that affect the respiratory tract (i.e., the „one airway” theory) and is often linked to asthma.

• #45 „What Causes Chronic Sinusitis?”Visit Sinus Service – Southwest Ohio ENT Specialists

  https://soents.com/what-causes-chronic-sinusitis/

  Patients with this form of CRS are more prone to the formation of nasal polyps. […] This form of sinusitis can account for 5-10% of all cases of chronic sinusitis that require surgery to repair. […] AERD, also known as Sampters Triad is a very severe form of chronic sinusitis where patients suffer from poorly controlled Asthma and severe sinusitis that is made worse by taking aspirin or other NSAID medications such as ibuprofen. […] This surprisingly common form of chronic sinusitis is due to a tooth infection (typically one of the upper molars) that has spread through the tooth root into the sinuses. […] Children and adults with cystic fibrosis are prone to a very severe form of chronic sinusitis that can develop at a very young age. […] This subtype of chronic sinusitis is increasing in prevalence due to the increasing number of patients treated with medications that decrease immune function (eg. Humira for arthritis).

• #46 Chronic Rhinosinusitis

  https://med.uth.edu/orl/texas-sinus-institute/patient-education/chronic-rhinosinusitis/

  Mucociliary Dysfunction Under normal circumstances, the lining of the sinuses is covered by a think blanket of mucus, which is propelled in a programmed fashion by cilia on the surface of the sinus lining. These cilia act as oars to move the mucus. Disruption of this activity leads to stagnation of the mucus, and eventually infection and CRS. […] OMC Compromise The ostiomeatal complex region is the common outflow channel for the anterior ethmoid, frontal and maxillary sinuses. Blockage of the OMC causes blockage of the upstream sinuses and CRS. […] Staphylococcal Superantigen Certain species of Staphylococcus can secrete substances (known as exotoxins) that can directly stimulate the immune system to produce a strong inflammatory reaction and CRS. […] Miscellaneous ASA triad (also known as Sampters triad) is characterized by nasal polyps, asthma, and aspirin intolerance. In these patients, aspirin produces a skin reaction, asthma, and even a severe reaction that can be life threatening. […] Churg-Straus Syndrome (also known as granulomatous vasculitis) results from a inflammation of blood vessels. Patients with this condition have severe asthma, sinusitis, and other related illnesses.

• #47 „What Causes Chronic Sinusitis?”Visit Sinus Service – Southwest Ohio ENT Specialists

  https://soents.com/what-causes-chronic-sinusitis/

  Chronic Rhinosinusitis (CRS) is a complex group of conditions that cause persistent inflammation of the nasal sinuses. […] It is important to remember that CRS does not have a single cause, but multiple causes. Each patients case is unique. […] In studies of US patients with chronic sinusitis, non eosinophilic sinusitis is the most common subtype. This form of sinusitis most likely arises from an underlying anatomic obstruction of the nasal sinuses, which prevents proper mucous drainage and airflow. This leads to chronic inflammation and makes patients prone to recurrent infections. […] An alternative cause may be from the formation of bacterial biofilms which can cause bacterial sinus infections that do not clear with oral antibiotics. […] This more severe form of sinusitis is typically found in patients with Asthma or other chronic inflammatory conditions that cause an increased number of eosinophils (a type of inflammatory white blood cell) to be present in sinus tissues.

• #48 Chronic Sinusitis: Treatment, Symptoms, and Causes

  https://www.healthline.com/health/chronic-sinusitis

  Other health conditions can cause chronic sinusitis too, including: asthma, a condition that causes chronic inflammation in your airways […] gastroesophageal reflux disease (GERD), a disease of your digestive tract […] human immunodeficiency virus (HIV), a virus that can weaken your immune system […] cystic fibrosis, a condition in which the mucus in your body builds up and doesnt drain properly, often causing bacterial infections.

• #49 Chronic Sinusitis: Symptoms, Causes & Treatment

  https://my.clevelandclinic.org/health/diseases/17700-chronic-sinusitis

  Chronic sinusitis may happen because you have: […] Conditions that block your airways, like asthma, allergies or cystic fibrosis. […] Weak immune system, which makes you more vulnerable to infections that cause chronic sinusitis. […] Chronic sinusitis treatment focuses on controlling or easing inflammation. […] Yes, it can, depending on the cause. For example, if nasal polyps cause chronic sinusitis, removing the polyps could cure the condition. […] Whats causing my chronic sinusitis?

• #50 „What Causes Chronic Sinusitis?”Visit Sinus Service – Southwest Ohio ENT Specialists

  https://soents.com/what-causes-chronic-sinusitis/

  Patients with this form of CRS are more prone to the formation of nasal polyps. […] This form of sinusitis can account for 5-10% of all cases of chronic sinusitis that require surgery to repair. […] AERD, also known as Sampters Triad is a very severe form of chronic sinusitis where patients suffer from poorly controlled Asthma and severe sinusitis that is made worse by taking aspirin or other NSAID medications such as ibuprofen. […] This surprisingly common form of chronic sinusitis is due to a tooth infection (typically one of the upper molars) that has spread through the tooth root into the sinuses. […] Children and adults with cystic fibrosis are prone to a very severe form of chronic sinusitis that can develop at a very young age. […] This subtype of chronic sinusitis is increasing in prevalence due to the increasing number of patients treated with medications that decrease immune function (eg. Humira for arthritis).

• #51 Chronic Rhinosinusitis | AAFP

  https://www.aafp.org/pubs/afp/issues/2017/1015/p500.html

  For example, granulomatous diseases such as vasculitis and sarcoidosis can cause chronic rhinosinusitis and nasal symptoms such as nasal crusting and epistaxis. […] Patients with chronic, recurrent sinus infections due to immunodeficiency and poor mucociliary clearance (e.g., cystic fibrosis, primary ciliary dyskinesia) may develop concurrent chronic rhinosinusitis. […] Many patients with chronic rhinosinusitis have allergies, asthma, and other less common comorbidities (e.g., vasculitides, granulomatous diseases, cystic fibrosis, immunodeficiency) that directly contribute to chronic rhinosinusitis. […] Odontogenic infections may also contribute to chronic rhinosinusitis.

• #52 Chronic Rhinosinusitis

  https://med.uth.edu/orl/texas-sinus-institute/patient-education/chronic-rhinosinusitis/

  Mucociliary Dysfunction Under normal circumstances, the lining of the sinuses is covered by a think blanket of mucus, which is propelled in a programmed fashion by cilia on the surface of the sinus lining. These cilia act as oars to move the mucus. Disruption of this activity leads to stagnation of the mucus, and eventually infection and CRS. […] OMC Compromise The ostiomeatal complex region is the common outflow channel for the anterior ethmoid, frontal and maxillary sinuses. Blockage of the OMC causes blockage of the upstream sinuses and CRS. […] Staphylococcal Superantigen Certain species of Staphylococcus can secrete substances (known as exotoxins) that can directly stimulate the immune system to produce a strong inflammatory reaction and CRS. […] Miscellaneous ASA triad (also known as Sampters triad) is characterized by nasal polyps, asthma, and aspirin intolerance. In these patients, aspirin produces a skin reaction, asthma, and even a severe reaction that can be life threatening. […] Churg-Straus Syndrome (also known as granulomatous vasculitis) results from a inflammation of blood vessels. Patients with this condition have severe asthma, sinusitis, and other related illnesses.

• #53 Chronic Sinusitis: Symptoms, Diagnosis, Causes & Treatment – Tua Saúde

  https://www.tuasaude.com/en/chronic-sinusitis/

  Chronic sinusitis is characterized by inflammation of the sinus membranes caused by infections (bacterial, viral or fungal), allergies, anatomical abnormalities (such as a deviated septum), inadequate or excessive use of antibiotics, or a weakened immune system. […] Symptoms of chronic sinusitis persist for over 12 weeks, and are usually related to infections (viral, fungal or bacterial) or allergies. Some factors can increase the risk for developing chronic sinusitis include: […] In addition, conditions like primary ciliary dyskinesia or Kartagener syndrome can also increase the risk for developing chronic sinusitis.

• #54 Sinus Infection | Causes, Symptoms & Treatment | ACAAI Public Website

  https://acaai.org/allergies/allergic-conditions/sinus-infection/

  Sinusitis is an inflammation of the sinuses. It is often caused by bacterial (germ) infection. Sometimes, viruses and fungi (molds) cause it. People with weak immune systems are more likely to develop bacterial or fungal sinus infection. Some people with allergies can have “allergic fungal sinus infection.” Acute sinus infection lasts three to eight weeks. A sinus infection lasting longer than eight weeks is considered chronic. […] People with these defects often suffer from chronic sinus infections. […] Sinus infections happen when you “catch a bug” and a virus, bacteria or mold settles in the sinuses and causes inflammation of the area lining your sinuses. The sinus cavity, which is like a dark cave, fills up with fluid and becomes blocked. This is the perfect place for germs to grow. People who have nasal allergies already have this sinus irritation. If you have a weak immune system, you are more likely to develop sinus infection from bacteria or mold. Other things that can cause sinus infections are colds, seasonal allergies, nasal polyps or a deviated septum. With a deviated septum one side of the nose is shifted over, and it makes it hard to drain mucous, so the sinuses get backed up.

• #55 „What Causes Chronic Sinusitis?”Visit Sinus Service – Southwest Ohio ENT Specialists

  https://soents.com/what-causes-chronic-sinusitis/

  Patients with this form of CRS are more prone to the formation of nasal polyps. […] This form of sinusitis can account for 5-10% of all cases of chronic sinusitis that require surgery to repair. […] AERD, also known as Sampters Triad is a very severe form of chronic sinusitis where patients suffer from poorly controlled Asthma and severe sinusitis that is made worse by taking aspirin or other NSAID medications such as ibuprofen. […] This surprisingly common form of chronic sinusitis is due to a tooth infection (typically one of the upper molars) that has spread through the tooth root into the sinuses. […] Children and adults with cystic fibrosis are prone to a very severe form of chronic sinusitis that can develop at a very young age. […] This subtype of chronic sinusitis is increasing in prevalence due to the increasing number of patients treated with medications that decrease immune function (eg. Humira for arthritis).

• #56 Chronic Rhinosinusitis | AAFP

  https://www.aafp.org/pubs/afp/issues/2017/1015/p500.html

  For example, granulomatous diseases such as vasculitis and sarcoidosis can cause chronic rhinosinusitis and nasal symptoms such as nasal crusting and epistaxis. […] Patients with chronic, recurrent sinus infections due to immunodeficiency and poor mucociliary clearance (e.g., cystic fibrosis, primary ciliary dyskinesia) may develop concurrent chronic rhinosinusitis. […] Many patients with chronic rhinosinusitis have allergies, asthma, and other less common comorbidities (e.g., vasculitides, granulomatous diseases, cystic fibrosis, immunodeficiency) that directly contribute to chronic rhinosinusitis. […] Odontogenic infections may also contribute to chronic rhinosinusitis.

• #57 Chronic Rhinosinusitis

  https://med.uth.edu/orl/texas-sinus-institute/patient-education/chronic-rhinosinusitis/

  Mucociliary Dysfunction Under normal circumstances, the lining of the sinuses is covered by a think blanket of mucus, which is propelled in a programmed fashion by cilia on the surface of the sinus lining. These cilia act as oars to move the mucus. Disruption of this activity leads to stagnation of the mucus, and eventually infection and CRS. […] OMC Compromise The ostiomeatal complex region is the common outflow channel for the anterior ethmoid, frontal and maxillary sinuses. Blockage of the OMC causes blockage of the upstream sinuses and CRS. […] Staphylococcal Superantigen Certain species of Staphylococcus can secrete substances (known as exotoxins) that can directly stimulate the immune system to produce a strong inflammatory reaction and CRS. […] Miscellaneous ASA triad (also known as Sampters triad) is characterized by nasal polyps, asthma, and aspirin intolerance. In these patients, aspirin produces a skin reaction, asthma, and even a severe reaction that can be life threatening. […] Churg-Straus Syndrome (also known as granulomatous vasculitis) results from a inflammation of blood vessels. Patients with this condition have severe asthma, sinusitis, and other related illnesses.

• #58 Chronic Rhinosinusitis—Microbiological Etiology, Potential Genetic Markers, and Diagnosis

  https://www.mdpi.com/1422-0067/25/6/3201

  Chronic rhinosinusitis (CRS) is a significant public health problem. Bacterial colonization and impaired mucociliary clearance play a significant role in the inflammatory process. Several inflammatory pathways and host defense elements are altered in CRS, which may contribute to observed differences in the microbiome. […] The literature data suggest that chronic inflammation may be caused by an abnormal immune response of the host mucosa rather than solely the presence of pathogens. In mucosal homeostasis, local irritants and pathogens are quickly and effectively eliminated through innate mucosal immune pathways without broader stimulation of the acquired immune system. The persistent inflammation seen in CRS may be due to a pathological imbalance in innate immune interactions between the host and the environment.

• #59 The Etiology and Pathogenesis of Chronic Rhinosinusitis: a Review of Current Hypotheses

  https://pmc.ncbi.nlm.nih.gov/articles/PMC4874491/

  The etiology and pathogenesis of CRS remain an active area of research. Fungi and bacteria have been implicated as important environmental factors contributing to chronic mucosal inflammation and have thus formed the basis of the fungal hypothesis, the superantigen hypothesis, the biofilm hypothesis, and the microbiome hypothesis. Increasing evidence, however, shows that these exogenous agents are unable to explain the full gamut of clinical variants, inflammatory profiles, and histologic patterns of CRS. Fungi and bacteria are thus generally viewed as disease modifiers of CRS, which accentuate, rather than cause, a dysfunctional immune response in CRS hosts. The eicosanoid hypothesis and the immune barrier hypothesis, in contrast, highlight the contribution of host variables in CRS pathogenesis. The immune barrier hypothesis specifically emphasizes the likely role of genetics and epigenetics in the development of functional deficits at the level of the sinonasal epithelium. These defects ultimately result in a dysfunctional inflammatory response when triggered by external stimuli, with some supporting data provided by the environmentally based hypotheses.

• #60 Chronic Rhinosinusitis, Nasal Polyps – Melbourne ENT Group

  https://melbentgroup.com.au/chronic-rhinosinusitis-crs/

  Chronic rhinosinusitis often has more complicated and elusive causes. […] Infections can certainly contribute to or worsen chronic rhinosinusitis, but people with the chronic condition usually have longstanding inflammation that cannot be explained by infection alone. […] In this form of rhinosinusitis, the swelling and irritation of the sinus lining may be caused by different factors, such as allergies to things in the air, irritation from things in the air, and infections. […] Some people with chronic rhinosinusitis develop a strong allergic response to fungi inside their sinuses. […] Allergies are much more common among people with chronic rhinosinusitis than they are among people in the general population. […] Exposure to cigarette smoke or certain environmental toxins, such as formaldehyde, can increase the risk of chronic rhinosinusitis. […] Some people develop chronic rhinosinusitis after having repeated viral infections, although it is not clear that the infections actually cause the chronic rhinosinusitis. […] A deviated septum may cause one nostril to be blocked, but it usually does not cause chronic rhinosinusitis.

• #61 Chronic Sinusitis: Causes, Symptoms, and Treatment

  https://patient.info/ears-nose-throat-mouth/acute-sinusitis/chronic-sinusitis

  Chronic sinusitis has a complicated set of causes. The main problem in chronic sinusitis is inflammation in the sinuses, and this can be caused by lots of things. The cause of chronic sinusitis differs from person to person, and there may be more than one cause present. […] It’s thought that certain viral infections could be the initial trigger for chronic sinusitis, perhaps by starting a process of inflammation that never fully resolves even after the virus has gone. Viral infections can also cause symptom flare-ups in people with chronic sinusitis. […] There might also be a link with bacterial infections, although this is complex, controversial, and not fully understood. It’s possible that chronic (long-lasting) bacterial infection may cause some cases of chronic sinusitis. […] Smoking is a strong risk factor for chronic sinusitis. Cigarette smoke damages the lining of the nose and sinuses, causing inflammation. It also leads to increased mucus production.

• #62 Sinusitis – Wikipedia

  https://en.wikipedia.org/wiki/Sinusitis

  Both smoking and secondhand smoke are associated with chronic rhinosinusitis. […] Exposure to fine particulate matter (PM2.5), which consists of particles less than 2.5 micrometers in diameter, has been associated with an increased risk of developing rhinosinusitis. […] Other diseases such as cystic fibrosis and granulomatosis with polyangiitis can also cause chronic sinusitis. […] Maxillary sinusitis may also develop from problems with the teeth, and these cases were calculated to be about 40% in one study and 50% in another.

• #63 Chronic Sinusitis: Causes, Symptoms, and Treatment

  https://patient.info/ears-nose-throat-mouth/acute-sinusitis/chronic-sinusitis

  Breathing in pollutants and other irritants, such as pesticides, dust, cleaning agents, and toxic gases can also cause inflammation in the nose and sinuses, leading to chronic sinusitis. […] Allergies are more common in people with chronic sinusitis. Allergies, such as to dust mites, animal fur, and mould, can cause chronic rhinitis, and may make chronic sinusitis symptoms worse. […] It’s possible that overgrowth or imbalance in fungi growth might contribute to chronic sinusitis, although this is probably only a factor in a small number of cases. […] Sometimes, changes in the shape of the nasal passages and the sinuses can cause narrowings, and prevent nasal mucus from draining properly. This can contribute to chronic sinusitis. […] Dental problems can cause maxillary sinusitis, such as gum disease, dental infections, including deep infections or abscesses, and complications from dental procedures.

• #64 Sinusitis – Wikipedia

  https://en.wikipedia.org/wiki/Sinusitis

  Both smoking and secondhand smoke are associated with chronic rhinosinusitis. […] Exposure to fine particulate matter (PM2.5), which consists of particles less than 2.5 micrometers in diameter, has been associated with an increased risk of developing rhinosinusitis. […] Other diseases such as cystic fibrosis and granulomatosis with polyangiitis can also cause chronic sinusitis. […] Maxillary sinusitis may also develop from problems with the teeth, and these cases were calculated to be about 40% in one study and 50% in another.

• #65 Chronic Rhinosinusitis—Microbiological Etiology, Potential Genetic Markers, and Diagnosis

  https://www.mdpi.com/1422-0067/25/6/3201

  The relationship between allergies and chronic sinusitis has been widely researched. Some reports in the literature support a cause-and-effect relationship between allergy and chronic sinusitis, while others do not confirm such an association. […] The presence of anaerobic microorganisms has been observed in studies on CRS, which can be explained by the selective pressure of antimicrobial agents that allow the growth of anaerobic organisms and the presence of conditions suitable for growth (i.e., sinus hypoxia). […] Chronic rhinosinusitis is a debilitating disease that negatively affects quality of life and poses an economic burden on society. […] Chronic sinusitis may be caused by exposure to air pollution. The severity of the disease and histopathological changes were also associated with increasing exposure to air pollution.

• #66 Chronic Sinusitis: Causes, Symptoms, and Treatment

  https://patient.info/ears-nose-throat-mouth/acute-sinusitis/chronic-sinusitis

  Breathing in pollutants and other irritants, such as pesticides, dust, cleaning agents, and toxic gases can also cause inflammation in the nose and sinuses, leading to chronic sinusitis. […] Allergies are more common in people with chronic sinusitis. Allergies, such as to dust mites, animal fur, and mould, can cause chronic rhinitis, and may make chronic sinusitis symptoms worse. […] It’s possible that overgrowth or imbalance in fungi growth might contribute to chronic sinusitis, although this is probably only a factor in a small number of cases. […] Sometimes, changes in the shape of the nasal passages and the sinuses can cause narrowings, and prevent nasal mucus from draining properly. This can contribute to chronic sinusitis. […] Dental problems can cause maxillary sinusitis, such as gum disease, dental infections, including deep infections or abscesses, and complications from dental procedures.

• #67 Chronic Sinusitis: Practice Essentials, Background, Anatomy

  https://emedicine.medscape.com/article/232791-overview

  Chronic sinusitis is an inflammatory process involving the paranasal sinus and persisting for at least 12 weeks. […] CRS may be noninfectious and associated with allergy, cystic fibrosis, gastroesophageal reflux, or exposure to environmental pollutants. Known risk factors include allergic rhinitis, nonallergic rhinitis, anatomic obstruction in the ostiomeatal complex, and immunologic disorders. […] Chronic sinusitis may be noninfectious and related to allergy, cystic fibrosis, gastroesophageal reflux, or exposure to environmental pollutants. […] The etiology of chronic sinusitis is multifactorial. The interaction between many systemic, local host, and environmental factors contribute to sinus inflammation and to the pathophysiology of the disease. Systemic factors include genetic diseases such as cystic fibrosis, conditions that cause immunodeficiency, autoimmune disease, idiopathic conditions such as Samter triad (aspirin-exacerbated respiratory disease), and acid reflux. Local host factors include sinonasal anatomic abnormalities, iatrogenic conditions such as scarring due to prior sinus surgery, neoplasm, or the presence of a foreign body, among others. Possible environmental factors that may contribute to the condition include the presence of biofilms and bacterial infection, as well as fungal infection, allergy, environmental pollutants, and smoking.

• #68 Chronic Sinusitis: Causes, Treatment, Prevention

  https://www.businessinsider.com/guides/health/conditions-symptoms/chronic-sinusitis

  Improper drainage from your sinuses: Foreign objects, nasal polyps, a deviated nasal septum, or any swellings inside your nose can prevent drainage. The resulting fluid buildup in your nose can lead to chronic sinusitis. […] Ciliary dysfunction: Cilia are tiny hair-like structures in your nose and nasal passages that guide the flow of fluids downward and outward. Damaged cilia which can result from smoking and vaping may cause a buildup of fluid that leads to inflamed sinuses. […] Chronic conditions: Health conditions like sleep apnea, sarcoidosis, and gastroesophageal reflux disease (GERD) can increase your risk of developing chronic sinusitis. […] Regular exposure to toxins, allergens, and air pollution: Harmful fumes and air pollution leave your sinuses little time to recover, which can mean they’re constantly inflamed. Pets can also increase your risk of chronic sinusitis, especially if you have allergies.

• #69 Chronic Sinusitis: Treatment, Symptoms, and Causes

  https://www.healthline.com/health/chronic-sinusitis

  Other health conditions can cause chronic sinusitis too, including: asthma, a condition that causes chronic inflammation in your airways […] gastroesophageal reflux disease (GERD), a disease of your digestive tract […] human immunodeficiency virus (HIV), a virus that can weaken your immune system […] cystic fibrosis, a condition in which the mucus in your body builds up and doesnt drain properly, often causing bacterial infections.

• #70 Chronic Sinusitis: Causes, Symptoms, and Treatment

  https://patient.info/ears-nose-throat-mouth/acute-sinusitis/chronic-sinusitis

  Sometimes, chronic sinusitis can develop as a result of another medical condition. Examples include cystic fibrosis, granulomatosis with polyangiitis, primary ciliary dyskinesia, and a severely weakened immune system. […] Chronic sinusitis also has links to other conditions. These don’t directly cause sinusitis, but likely share underlying causes with it. They may also make sinusitis worse, and vice versa. Examples include asthma, chronic obstructive pulmonary disease (COPD), and non-steroidal anti-inflammatory drug (NSAID) sensitivity.

• #71 Chronic Sinusitis: Treatment, Symptoms, and Causes

  https://www.healthline.com/health/chronic-sinusitis

  Other health conditions can cause chronic sinusitis too, including: asthma, a condition that causes chronic inflammation in your airways […] gastroesophageal reflux disease (GERD), a disease of your digestive tract […] human immunodeficiency virus (HIV), a virus that can weaken your immune system […] cystic fibrosis, a condition in which the mucus in your body builds up and doesnt drain properly, often causing bacterial infections.

• #72 Chronic Sinusitis: Practice Essentials, Background, Anatomy

  https://emedicine.medscape.com/article/232791-overview

  Chronic sinusitis is an inflammatory process involving the paranasal sinus and persisting for at least 12 weeks. […] CRS may be noninfectious and associated with allergy, cystic fibrosis, gastroesophageal reflux, or exposure to environmental pollutants. Known risk factors include allergic rhinitis, nonallergic rhinitis, anatomic obstruction in the ostiomeatal complex, and immunologic disorders. […] Chronic sinusitis may be noninfectious and related to allergy, cystic fibrosis, gastroesophageal reflux, or exposure to environmental pollutants. […] The etiology of chronic sinusitis is multifactorial. The interaction between many systemic, local host, and environmental factors contribute to sinus inflammation and to the pathophysiology of the disease. Systemic factors include genetic diseases such as cystic fibrosis, conditions that cause immunodeficiency, autoimmune disease, idiopathic conditions such as Samter triad (aspirin-exacerbated respiratory disease), and acid reflux. Local host factors include sinonasal anatomic abnormalities, iatrogenic conditions such as scarring due to prior sinus surgery, neoplasm, or the presence of a foreign body, among others. Possible environmental factors that may contribute to the condition include the presence of biofilms and bacterial infection, as well as fungal infection, allergy, environmental pollutants, and smoking.

• #73 Sinusitis – Wikipedia

  https://en.wikipedia.org/wiki/Sinusitis

  Both smoking and secondhand smoke are associated with chronic rhinosinusitis. […] Exposure to fine particulate matter (PM2.5), which consists of particles less than 2.5 micrometers in diameter, has been associated with an increased risk of developing rhinosinusitis. […] Other diseases such as cystic fibrosis and granulomatosis with polyangiitis can also cause chronic sinusitis. […] Maxillary sinusitis may also develop from problems with the teeth, and these cases were calculated to be about 40% in one study and 50% in another.

• #74 „What Causes Chronic Sinusitis?”Visit Sinus Service – Southwest Ohio ENT Specialists

  https://soents.com/what-causes-chronic-sinusitis/

  Patients with this form of CRS are more prone to the formation of nasal polyps. […] This form of sinusitis can account for 5-10% of all cases of chronic sinusitis that require surgery to repair. […] AERD, also known as Sampters Triad is a very severe form of chronic sinusitis where patients suffer from poorly controlled Asthma and severe sinusitis that is made worse by taking aspirin or other NSAID medications such as ibuprofen. […] This surprisingly common form of chronic sinusitis is due to a tooth infection (typically one of the upper molars) that has spread through the tooth root into the sinuses. […] Children and adults with cystic fibrosis are prone to a very severe form of chronic sinusitis that can develop at a very young age. […] This subtype of chronic sinusitis is increasing in prevalence due to the increasing number of patients treated with medications that decrease immune function (eg. Humira for arthritis).

• #75 Chronic Rhinosinusitis

  https://med.uth.edu/orl/texas-sinus-institute/patient-education/chronic-rhinosinusitis/

  Biofilms Biofilms are complex, three-dimensional structures of living bacteria. They have been identified in approximately 2533% of patients with CRS in some studies. […] Fungal Infection Cultures of sinus secretions from patients with CRS have grown fungus. Furthermore, it has been shown that the immune system of patients with CRS have a greater response when exposed to fungal proteins at least in the laboratory. […] Genetic Disorders Patients with cystic fibrosis (CF), a hereditary condition that effects mostly the lungs, also develop significant CRS. CF and other genetic diseases may be causes of CRS. […] Osteitis The bone in the walls of the sinuses of patients with severe CRS undergoes a remodeling process that produces thicker, but abnormal bone. This finding, known as osteitis, suggests that changes in the bone may contribute to CRS.

• #76 Chronic Sinusitis: Causes, Treatment, Prevention

  https://www.businessinsider.com/guides/health/conditions-symptoms/chronic-sinusitis

  Improper drainage from your sinuses: Foreign objects, nasal polyps, a deviated nasal septum, or any swellings inside your nose can prevent drainage. The resulting fluid buildup in your nose can lead to chronic sinusitis. […] Ciliary dysfunction: Cilia are tiny hair-like structures in your nose and nasal passages that guide the flow of fluids downward and outward. Damaged cilia which can result from smoking and vaping may cause a buildup of fluid that leads to inflamed sinuses. […] Chronic conditions: Health conditions like sleep apnea, sarcoidosis, and gastroesophageal reflux disease (GERD) can increase your risk of developing chronic sinusitis. […] Regular exposure to toxins, allergens, and air pollution: Harmful fumes and air pollution leave your sinuses little time to recover, which can mean they’re constantly inflamed. Pets can also increase your risk of chronic sinusitis, especially if you have allergies.

• #77 The Etiology and Pathogenesis of Chronic Rhinosinusitis: a Review of Current Hypotheses

  https://pmc.ncbi.nlm.nih.gov/articles/PMC4874491/

  The etiology and pathogenesis of CRS remain an active area of research. Fungi and bacteria have been implicated as important environmental factors contributing to chronic mucosal inflammation and have thus formed the basis of the fungal hypothesis, the superantigen hypothesis, the biofilm hypothesis, and the microbiome hypothesis. Increasing evidence, however, shows that these exogenous agents are unable to explain the full gamut of clinical variants, inflammatory profiles, and histologic patterns of CRS. Fungi and bacteria are thus generally viewed as disease modifiers of CRS, which accentuate, rather than cause, a dysfunctional immune response in CRS hosts. The eicosanoid hypothesis and the immune barrier hypothesis, in contrast, highlight the contribution of host variables in CRS pathogenesis. The immune barrier hypothesis specifically emphasizes the likely role of genetics and epigenetics in the development of functional deficits at the level of the sinonasal epithelium. These defects ultimately result in a dysfunctional inflammatory response when triggered by external stimuli, with some supporting data provided by the environmentally based hypotheses.

• #78 Chronic Rhinosinusitis—Microbiological Etiology, Potential Genetic Markers, and Diagnosis

  https://www.mdpi.com/1422-0067/25/6/3201

  Any abnormal activation or lack of immune system suppression can lead to chronic inflammation. Since bacterial pathogens are frequently observed in CRS, it has been speculated that bacterial dysbiosis plays an important role in initiating or contributing to CRS. […] Chronic rhinosinusitis is characterized by persistent inflammation, a dysregulated immune response and interactions with microorganisms, which together cause epithelial barrier dysfunction, tissue remodeling, and clinical symptoms.

• #79 The Etiology and Pathogenesis of Chronic Rhinosinusitis: a Review of Current Hypotheses

  https://pmc.ncbi.nlm.nih.gov/articles/PMC4874491/

  The etiology and pathogenesis of CRS remain an active area of research. Fungi and bacteria have been implicated as important environmental factors contributing to chronic mucosal inflammation and have thus formed the basis of the fungal hypothesis, the superantigen hypothesis, the biofilm hypothesis, and the microbiome hypothesis. Increasing evidence, however, shows that these exogenous agents are unable to explain the full gamut of clinical variants, inflammatory profiles, and histologic patterns of CRS. Fungi and bacteria are thus generally viewed as disease modifiers of CRS, which accentuate, rather than cause, a dysfunctional immune response in CRS hosts. The eicosanoid hypothesis and the immune barrier hypothesis, in contrast, highlight the contribution of host variables in CRS pathogenesis. The immune barrier hypothesis specifically emphasizes the likely role of genetics and epigenetics in the development of functional deficits at the level of the sinonasal epithelium. These defects ultimately result in a dysfunctional inflammatory response when triggered by external stimuli, with some supporting data provided by the environmentally based hypotheses.

• #80 Chronic Rhinosinusitis—Microbiological Etiology, Potential Genetic Markers, and Diagnosis

  https://www.mdpi.com/1422-0067/25/6/3201

  Chronic rhinosinusitis (CRS) is a significant public health problem. Bacterial colonization and impaired mucociliary clearance play a significant role in the inflammatory process. Several inflammatory pathways and host defense elements are altered in CRS, which may contribute to observed differences in the microbiome. […] The literature data suggest that chronic inflammation may be caused by an abnormal immune response of the host mucosa rather than solely the presence of pathogens. In mucosal homeostasis, local irritants and pathogens are quickly and effectively eliminated through innate mucosal immune pathways without broader stimulation of the acquired immune system. The persistent inflammation seen in CRS may be due to a pathological imbalance in innate immune interactions between the host and the environment.

• #81 Chronic Rhinosinusitis—Microbiological Etiology, Potential Genetic Markers, and Diagnosis

  https://www.mdpi.com/1422-0067/25/6/3201

  Any abnormal activation or lack of immune system suppression can lead to chronic inflammation. Since bacterial pathogens are frequently observed in CRS, it has been speculated that bacterial dysbiosis plays an important role in initiating or contributing to CRS. […] Chronic rhinosinusitis is characterized by persistent inflammation, a dysregulated immune response and interactions with microorganisms, which together cause epithelial barrier dysfunction, tissue remodeling, and clinical symptoms.

• #82 Chronic Rhinosinusitis—Microbiological Etiology, Potential Genetic Markers, and Diagnosis

  https://www.mdpi.com/1422-0067/25/6/3201

  Any abnormal activation or lack of immune system suppression can lead to chronic inflammation. Since bacterial pathogens are frequently observed in CRS, it has been speculated that bacterial dysbiosis plays an important role in initiating or contributing to CRS. […] Chronic rhinosinusitis is characterized by persistent inflammation, a dysregulated immune response and interactions with microorganisms, which together cause epithelial barrier dysfunction, tissue remodeling, and clinical symptoms.

• #83 Chronic Sinusitis: Practice Essentials, Background, Anatomy

  https://emedicine.medscape.com/article/232791-overview

  Chronic sinusitis is an inflammatory process involving the paranasal sinus and persisting for at least 12 weeks. […] CRS may be noninfectious and associated with allergy, cystic fibrosis, gastroesophageal reflux, or exposure to environmental pollutants. Known risk factors include allergic rhinitis, nonallergic rhinitis, anatomic obstruction in the ostiomeatal complex, and immunologic disorders. […] Chronic sinusitis may be noninfectious and related to allergy, cystic fibrosis, gastroesophageal reflux, or exposure to environmental pollutants. […] The etiology of chronic sinusitis is multifactorial. The interaction between many systemic, local host, and environmental factors contribute to sinus inflammation and to the pathophysiology of the disease. Systemic factors include genetic diseases such as cystic fibrosis, conditions that cause immunodeficiency, autoimmune disease, idiopathic conditions such as Samter triad (aspirin-exacerbated respiratory disease), and acid reflux. Local host factors include sinonasal anatomic abnormalities, iatrogenic conditions such as scarring due to prior sinus surgery, neoplasm, or the presence of a foreign body, among others. Possible environmental factors that may contribute to the condition include the presence of biofilms and bacterial infection, as well as fungal infection, allergy, environmental pollutants, and smoking.

• #84 The Etiology and Pathogenesis of Chronic Rhinosinusitis: a Review of Current Hypotheses

  https://pmc.ncbi.nlm.nih.gov/articles/PMC4874491/

  The etiology and pathogenesis of CRS remain an active area of research. Fungi and bacteria have been implicated as important environmental factors contributing to chronic mucosal inflammation and have thus formed the basis of the fungal hypothesis, the superantigen hypothesis, the biofilm hypothesis, and the microbiome hypothesis. Increasing evidence, however, shows that these exogenous agents are unable to explain the full gamut of clinical variants, inflammatory profiles, and histologic patterns of CRS. Fungi and bacteria are thus generally viewed as disease modifiers of CRS, which accentuate, rather than cause, a dysfunctional immune response in CRS hosts. The eicosanoid hypothesis and the immune barrier hypothesis, in contrast, highlight the contribution of host variables in CRS pathogenesis. The immune barrier hypothesis specifically emphasizes the likely role of genetics and epigenetics in the development of functional deficits at the level of the sinonasal epithelium. These defects ultimately result in a dysfunctional inflammatory response when triggered by external stimuli, with some supporting data provided by the environmentally based hypotheses.

• #85 Chronic Rhinosinusitis—Microbiological Etiology, Potential Genetic Markers, and Diagnosis

  https://www.mdpi.com/1422-0067/25/6/3201

  Studies have confirmed that CRS is a multifactorial condition. The predisposition of the host to develop the condition plays a key role, and a variety of external factors can potentially trigger or modify the disease in a predisposed individual. An increasingly common hypothesis is that innate immune defects, which disrupt normal mucosal homeostasis and allow microorganisms and airborne particles to stimulate the immune response, are responsible for the incidence of CRS. […] Numerous hypotheses regarding the pathogenesis of CRS have been described in the literature. Researchers have mentioned that etiology may be related to superantigens, bacterial biofilm, microbiome, the presence of fungi, the action of eicosanoids, and the functioning of the immune system. […] Chronic sinusitis is also favored by nasal polyps, deviated nasal septum, facial trauma, respiratory infections, allergies, and other diseases, such as cystic fibrosis, gastroesophageal reflux, HIV, immune diseases, and exposure to environmental pollution.

• #86 The Etiology and Pathogenesis of Chronic Rhinosinusitis: a Review of Current Hypotheses

  https://pmc.ncbi.nlm.nih.gov/articles/PMC4874491/

  While the relative importance of each factor remains a matter of debate, there is an emerging consensus on two points: (1) specific factors likely vary in importance in individual patients and (2) CRS is an antegrade process in that the mucosal inflammation is most commonly triggered by exogenous agents inhaled through the nose. Overall, this leads to the concept that CRS is most inclusively described as a dysfunctional interaction that occurs at the site of interface between the host and the environment—the sinonasal mucosa. […] Overall, six broad hypotheses on CRS etiology and pathogenesis have thus far been proposed, each describing a central role for one or more aspects of these factors: (1) the fungal hypothesis, (2) the superantigen hypothesis, (3) the biofilm hypothesis, and (4) the microbiome hypothesis, all of which emphasize key environmental factors, and (5) the eicosanoid hypothesis and (6) the immune barrier hypothesis, which focus on host factors.

• #87 4 Unexpected Causes of Chronic Sinus Pain | Harley Street ENT Clinic

  https://www.harleystreetent.com/blog/four-unexpected-causes-of-chronic-sinus-pain

  In our modern world filled with pollution, chemicals, and allergens, it’s no surprise that environmental factors can contribute to sinus pain. […] Chronic sinus pain can sometimes be a symptom of an underlying medical condition that extends beyond the sinuses themselves. […] In these cases, treating the root cause of the problem is essential for long-term relief. […] If allergies contribute to your sinus pain, these management strategies may be recommended: […] By working closely with your healthcare provider, you can develop a treatment plan that addresses the causes of your chronic sinus pain and provides lasting relief. […] Understanding the causes of chronic sinus pain is the first step towards finding effective treatment and reclaiming your quality of life.

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