Materiały źródłowe

• #1 Henoch-Schönlein Purpura (IgA Vasculitis): Rapid Evidence Review | AAFP

  https://www.aafp.org/pubs/afp/issues/2020/0815/p229.html

  IgA vasculitis occurs in 3.0 to 26.7 out of 100,000 children and 0.8 to 1.8 out of 100,000 adults each year. The mean age of onset in children is six years; onset ranged from 32 to 50 years of age in several adult case series. More than 90% of cases occur in children younger than 10 years. There is a slight disease predominance in males. In children, onset is more common during the fall and winter, but no seasonal pattern has been consistently shown in adults. IgA vasculitis is milder in children younger than two years, but more severe in adults, with worse outcomes. […] Systematic reviews have shown that steroids do not prevent complications and should not be used prophylactically. However, randomized trials have demonstrated success with high-dose steroids, cyclosporine, and mycophenolate in treating glomerulonephritis and other complications. Long-term prognosis depends on the extent of renal involvement. Six months of follow-up is prudent to assess for disease relapse or remission.

• #1 IgA Vasculitis (Henoch-Schonlein Purpura): Practice Essentials, Background, Pathophysiology

  https://emedicine.medscape.com/article/984105-overview

  In the United States, the incidence of IgAV is approximately 14-15 cases per 100,000 population in children, compared with 1-3 cases per 100,000 per year in adults. […] Worldwide, the incidence rates of IgAV in children and adolescents aged 15 years vary widely, ranging from 3.5 per 100,000 persons in Japan to 26.7 per 100,000 persons in Scotland. […] In the United Kingdom overall, the estimated annual incidence of IgAV is 20.4 cases per 100,000 population aged 17 years, with a peak incidence of 70 per 100,000 in children of age four to six years. […] Incidence rates reported elsewhere in Europe are 17.5 per 100,000 in Sweden and 18.6 per 100,000 persons in France. […] Surveys from Taiwan and the Czech Republic report a lower incidence of 10 per 100,000 in children 17 years of age, with a peak incidence at five to seven years of age.

• #1 IgA Vasculitis (Henoch-Schonlein Purpura): Practice Essentials, Background, Pathophysiology

  https://emedicine.medscape.com/article/984105-overview

  IgAV is the most common vasculitis in childhood. The incidence decreases with age, but in adults the severity increases with age. […] The prevalence of IgAV peaks in children aged 3-10 years, with the mean age at presentation being 6 years, but the condition is also seen in adults. […] It has been reported that IgAV will occur in 10-30 per 100,000 children younger than 17 years will develop IgAV. […] There is a strong ethnic influence on the incidence of the disease, with approximately 70 cases per 100,000 children annually in Asia. […] In the Northern Hemisphere, the disease occurs mostly between November and January. […] IgAV has typically been reported to be more common in males, with a male-to-female ratio ranging from 1.5-2:1, but some studies have found a more equal distribution between the sexes.

• #1 Henoch–Schönlein purpura – Wikipedia

  https://en.wikipedia.org/wiki/Henoch%E2%80%93Sch%C3%B6nlein_purpura

  HSP occurs more often in children than in adults, and usually follows an upper respiratory tract infection. Half of affected patients are below the age of six, and 90% are under ten. It occurs about twice as often in boys as in girls. The incidence of HSP in children is about 20 per 100,000 children per year, making it the most common vasculitis in children. […] Cases of HSP may occur anytime throughout the year, but some studies have found that fewer cases occur during the summer months.

• #1 Henoch-Schönlein Purpura | 5-Minute Clinical Consult

  https://www.unboundmedicine.com/5minute/view/5-Minute-Clinical-Consult/1688445/all/Henoch_Sch%C3%B6nlein_Purpura

  Henoch-Schnlein purpura (HSP) is a nonthrombocytopenic, predominantly IgA-mediated, small vessel vasculitis that affects multiple organ systems and occurs in both children and adults. […] Annual incidence: estimated 29.9/100,000 children and 0.1 to 1.8/100,000 adults. […] Peak incidence: age 4 to 6 years; 90% of patients with HSP are 10 years of age; however, has been reported in patients aged 6 months to 75 years old. […] Gender: Male-to-female ratio is between 1.2:1 and 1.8:1. […] Race/ethnicity: most common in Caucasians and Asians; less common among African Americans. […] Annual prevalence: 10 to 22/100,000 persons; more common in fall and winter.

• #1 Henoch-Schonlein purpura » Global Autoimmune Institute

  https://www.autoimmuneinstitute.org/autoimmune-resources/autoimmune-diseases-list/henoch-schonlein-purpura/

  HSP, also known as IgA vasculitis, is characterized by inflammation of the small blood vessels located in the skin, joints, intestines, and kidneys, sometimes accompanied by bleeding. […] Those between the ages of 4 and 6 are most commonly affected. Males tend to be more commonly affected by HSP than females. African American children are less commonly affected by the condition than white or Asian children. Environmental triggers include colds, chickenpox, strep throat, measles, and hepatitis. Many recorded cases of HSP have followed upper respiratory infections. […] IgA vasculitis update: Epidemiology, pathogenesis, and biomarkers (2022)

• #1 Common Seasonal Pathogens and Epidemiology of Henoch-Schönlein Purpura Among Children

  https://pmc.ncbi.nlm.nih.gov/articles/PMC10998156/

  In this cohort study of 9790 children with HSP and 757110 children with an infectious disease, time-series analysis of a prospective national surveillance cohort from 2015 to 2023 revealed that 37.3% of HSP incidence was potentially associated with Streptococcus pneumoniae and that 25.6% of HSP incidence was potentially associated with Streptococcus pyogenes. […] These findings underscore the potentially significant role of S pneumoniae and S pyogenes in the burden of childhood HSP, suggesting that preventive measures could prove effective for this common form of childhood vasculitis. […] Henoch-Schnlein purpura (HSP) is the most common type of vasculitis in children. […] The factors that trigger the disease are poorly understood. […] Although several viruses and seasonal bacterial infections have been associated with HSP, differentiating the specific associations of these pathogens with the onset of HSP remains a challenge due to their overlapping seasonal patterns.

• #1 Common Seasonal Pathogens and Epidemiology of Henoch-Schönlein Purpura Among Children – PubMed

  https://pubmed.ncbi.nlm.nih.gov/38578638/

  The study included 9790 children with HSP (median age, 5 years [IQR, 4-8 years]; 5538 boys [56.4%]) and 757 110 children with the infectious diseases included in the study (median age, 0.7 years [IQR, 0.2-2 years]; 393 697 boys [52.0%]). The incidence of HSP decreased significantly after implementation of NPIs in March 2020 (-53.6%; 95% CI, -66.6% to -40.6%; P .001) and increased significantly after the relaxation of NPIs in April 2021 (37.2%; 95% CI, 28.0%-46.3%; P .001). […] This study found that significant changes in the incidence of HSP simultaneously with major shifts in circulating pathogens after NPIs for the COVID-19 pandemic indicated that approximately 60% of HSP incidence was potentially associated with pneumococcus and group A streptococcus. This finding suggests that preventive measures against these pathogens could reduce the incidence of pediatric HSP.

• #1 An Investigation of the Relationship between Henoch-Schönlein Purpura and Viral Infection in Korea Using the Health Insurance Database

  https://www.mdpi.com/2077-0383/13/5/1290

  (1) Background: This study investigated the epidemiology and viral connections of Henoch–Schönlein purpura (HSP) using information from the Korea Disease Control and Prevention Agency and the Health Insurance Review and Assessment database. […] (2) Method: Between 2016 and 2019, a total of 25,443 patients with HSP were identified, with 51.3% of patients under the age of 20 years and the highest incidence in March. […] (4) Conclusions: The incidence of HSP was associated with rotavirus, bocavirus, parainfluenza virus, and respiratory syncytial virus in individuals under 20 years of age, whereas adenovirus, respiratory syncytial virus, and norovirus were associated with individuals above that age. […] HSP is the most common vasculitis in childhood, with an annual incidence of 26.7/100,000, demonstrating that it occurs 2–33-fold more frequently in infants than in adults; recent studies suggest an equal incidence in males and females.

• #1 EPIDEMIOLOGY AND CLINICAL CHARACTERISTICS OF HENOCH-SCHÖNLEIN PURPURA ASSOCIATED WITH EPSTEIN-BARR VIRUS INFECTION | Mediterranean Journal of Hematology and Infectious Diseases

  https://www.mjhid.org/index.php/mjhid/article/view/4714

  Henoch-Schnlein purpura (HSP) is an immune-mediated vasculitis, and the formation of immune complexes may be triggered by exposure to Epstein-Barr virus (EBV) infection. […] We performed a five-year case-control study to evaluate the epidemiology and clinical characteristics of HSP associated with EBV infection. […] The incidence of EBV-triggered HSP was 4.2%, while EBV infection in children with HSP was 0.9%; […] Both cellular and humoral immunity were involved in the pathogenesis of EBV-triggered HSP, leading to increased production of inflammatory mediators and immunoglobulins. Those events may cause or promote the development of systemic vessel vasculitis.

• #1 Henoch Schonlein Purpura (HSP) – almostadoctor

  https://almostadoctor.co.uk/encyclopedia/henoch-schonlein-purpura-hsp

  Henoch-Schonlein Purpura (HSP) is a vasculitis that most commonly occurs in children. It is the most common vasculitis of childhood, and typically presents in children aged between 2-8. […] 6-20 cases per 100 000 annually. […] 90% of cases occurs in children. […] 50-90% of cases have a preceding URTI (studies vary). […] Caucasians more likely to be affected than other races. […] Typically occurs in winter.

• #1 Henoch-Schönlein Purpura (HSP) | Doctor

  https://patient.info/doctor/henoch-schonlein-purpura-pro

  Henoch-Schnlein purpura (HSP) is a rare condition but is the most common form of systemic vasculitis in children; 90% of cases occur in childhood under the age of 10 years. The peak prevalence is in children aged 4-6 years. It is estimated to affect 10 to 20 per 100,000 children per year. In the UK, the estimated annual incidence is 6-20 cases per 100,000 population. White people are more often affected than other ethnic groups. […] Renal involvement occurs in up to 55% of children with HSP but is usually not serious, with manifestation ranging from microscopic haematuria and mild proteinuria to nephrotic and nephritic syndrome and renal failure. Less than 1% of patients with HSP progress to end-stage kidney disease. The renal prognosis is worse in older children and in adults. […] HSP spontaneously resolves in 94% of children and 89% of adults. However, a subset of patients experience renal involvement that can persist and relapse years later. Long-term prognosis depends on the extent of renal involvement.

• #1 Henoch-Schönlein Purpura in Children: An Updated Review

  https://www.eurekaselect.com/node/181781/4

  Henoch-Schnlein purpura (HSP) is an IgA-mediated systemic small vessel vasculitis with a predilection for the skin, gastrointestinal tract, joints, and kidneys. It is the most common form of systemic vasculitis in children. […] Globally, the incidence of HSP is 10 to 20 cases per 100,000 children per year. Approximately 90% of cases occur in children between 2 and 10 years of age, with a peak incidence at 4 to 7 years. […] Most cases of HSP have an excellent outcome, with renal involvement being the most important prognostic factor in determining morbidity and mortality.

• #1 :: PGHN :: Pediatric Gastroenterology, Hepatology & Nutrition

  https://pghn.org/DOIx.php?id=10.5223/pghn.2016.19.3.175

  The peak incidence of HSP was in the winter (33.0%) and lowest in the summer (11.8%), which is in keeping with findings from previous studies. […] The rate of renal involvement was relatively low in Korea compared to that of other countries. […] In this study, joint symptoms were more frequently observed in younger children. […] In this study, clinical manifestations were assessed by diving patients into two groups based on a reference age of 7 years. […] In this study, there was an association between GI symptoms and scrotal involvement, but no significant association was observed between scrotal involvement and renal involvement. […] In children with HSP, the incidence of renal involvement and nephrotic syndrome is higher in those presenting at an older age, and in those patients with severe abdominal pain or GI hemorrhage.

• #1 IgA vasculitis – Henoch-Schonlein purpura: MedlinePlus Medical EncyclopediaLock

  https://medlineplus.gov/ency/article/000425.htm

  IgA vasculitis is a disease that involves purple spots on the skin, joint pain, gastrointestinal problems, and glomerulonephritis (a type of kidney disorder). It is also known as Henoch-Schönlein purpura (HSP). […] The syndrome is mostly seen in children between ages 3 and 15 years, but it may be seen in adults. It is more common in boys than in girls. Many people who develop this disease had an upper respiratory infection in the weeks before. […] The disease most often gets better on its own. Two thirds of children with IgA vasculitis have only one episode. One third of children have more episodes. People should have close medical follow-up for 6 months after episodes to look for signs of kidney disease. Adults have a greater risk of developing chronic kidney disease.

• #1 IgA Vasculitis (Henoch–Schönlein Purpura): An Update on Treatment

  https://www.mdpi.com/2077-0383/13/21/6621

  Henoch–Schönlein purpura (HSP) is a systemic small-vessel vasculitis whose main anatomopathological feature is the deposition of IgA1-dominant immune complexes (ICs) in the affected tissues, and its nomenclature has been recently changed to immunoglobulin A vasculitis (IgAV) in the latest consensual classification of vasculitis. An annual incidence of IgAV in children of around 3 to 27 cases per 100,000 cases has been reported, representing the most frequent vasculitis in childhood. […] In Northwestern Spain, an epidemiological study conducted over 20 years found a higher prevalence of IgAV in children during fall and winter, and reported an annual incidence rate of 10.45 per 100,000 cases in children under 14 years of age. […] Additionally, the frequency of IgAV in adults is about 10 times lower than in children, with an annual incidence of 0.1 to 14 per 100,000 people. […] The frequency of glomerulonephritis (referred to as IgAV nephritis) in adults is higher than in children and tends to present more severely, with around 10–30% of those affected eventually progressing to end-stage renal disease.

• #1

  https://link.springer.com/article/10.1007/s00467-014-2815-6

  HenochSchnlein purpura is one of most common types of systemic vasculitis in childhood, with a slightly higher incidence in boys than in girls. Between six and 24 per 100,000 children below 17 years of age are affected, depending on the ethnic background of the children. The incidence is highest in children aged 47 years (up to 70 cases/100,000 children per year) and in children of Asian descent. […] A high proportion of HSP patients (30-50 %) either have or develop hematuria and/or proteinuria as a symptom(s) of HSPN, both of which are mostly of minor extent and self-limited. Of all HSP patients with abnormal urinalysis, a minority develop severe glomerulonephritis, which is associated with an increased risk of long-term chronic kidney disease. […] The risk of suffering from clinically severe HSPN with a higher risk of long-term renal sequelae seems to increase with age, but the prognosis of equally severe HSPN is not different in children and adults. […] The estimated risk of chronic kidney disease in pediatric HSPN patients with nephritic or nephrotic syndrome is 20 %.

• #1 Henoch-Schönlein Purpura : Johns Hopkins Vasculitis CenterFacebookTwitterYouTube

  https://www.hopkinsvasculitis.org/types-vasculitis/henochschnlein-purpura/

  HSP is the most common form of vasculitis in children, with an annual incidence on the order of 140 cases/million persons. The mean age of patients with HSP is 5.9 years. […] More than 90% of cases occur in children. The disease usually resolves within a few weeks. However, adult cases are sometimes more difficult. […] HSP patients who experience this symptom should be followed more closely, with regular testing of their urine for blood and protein. Recurrences, found in 33% of patients, usually develop within the first few months after resolution of the first bout.

• #1 Incidence and risk factors for recurrent Henoch-Schönlein purpura in children from a 16-year nationwide database | Pediatric Rheumatology | Full Text

  https://ped-rheum.biomedcentral.com/articles/10.1186/s12969-018-0247-8

  The recurrence rate (16.3%) in our study was within the range described by a previous study (2.7%66.2%). […] Our finding that allergic rhinitis was an independent risk factor for HSP was in line with studies reporting an increased risk of HSP in atopic children. […] Our study showed a significantly increased association between steroid use for 10 days regardless of early initiation and the risk of recurrence. […] The average duration between the first and second HSP episodes was 9.2 months. […] For the early detection of recurrence, it may be worth considering following up patients with the first HSP episode for at least 9.2 months and those with a second HSP episode for another 6.4 months.

• #1 Incidence and risk factors for recurrent Henoch-Schönlein purpura in children from a 16-year nationwide database | Pediatric Rheumatology | Full Text

  https://ped-rheum.biomedcentral.com/articles/10.1186/s12969-018-0247-8

  Various predictors for recurrence, including greater joint and gastrointestinal involvement at diagnosis, history of infection, elevated erythrocyte sedimentation rate, steroid treatment, and renal manifestations, have been identified but they are inconsistent. […] The incidence of patients with secondary (recurrent) HSP was 7.05 per 100 person-years (male incidence, 8.29; female incidence, 4.96). […] The percentage of patients free of a second HSP episode was 94.7%, 88.1%, 84.0%, 55.3%, and 25.0% for patients with steroid initiation 14 days and duration 10 days, no steroid use, initiation 14 days and duration 10 days, initiation 14 days and duration 10 days, respectively. […] Our results revealed that renal involvement, underlying allergic rhinitis, and steroid treatment for 10 days were risk factors for HSP recurrence in children, regardless of age, sex, and income levels.

• #1 Henoch-Schonlein Purpura | Children’s Hospital of Philadelphia

  https://www.chop.edu/conditions-diseases/henoch-schonlein-purpura

  Henoch-Schönlein purpura (HSP) is a form of vasculitis, a condition that involves inflammation of the blood vessels. It can affect any organ of the body. […] HSP is the most common form of vasculitis in childhood and affects about 20 in 100,000 children. It occurs most commonly in children ages 2-6, although it can occur at any age. […] The most serious potential complication of Henoch-Schönlein purpura is kidney damage — which can be irreversible. For this reason, children with HSP should be carefully monitored for the first 6 months after diagnosis. Testing should include regular blood pressure checks and urine analysis. […] About a third of children with HSP will experience a recurrence of symptoms within the first year after disease onset. In most cases, the recurrence is less severe and lasts a shorter period of time than the initial onset of symptoms. […] Women with a history of Henoch-Schönlein purpura, regardless of prior kidney involvement, are at increased risk of developing preeclampsia during pregnancy. […] In rare cases, HSP can lead to permanent damage to the kidneys, which may require life-long management by a nephrologist.

• #1 Common Seasonal Pathogens and Epidemiology of Henoch-Schönlein Purpura Among Children – PubMed

  https://pubmed.ncbi.nlm.nih.gov/38578638/

  Henoch-Schnlein purpura (HSP) is the most common type of vasculitis in children. The factors that trigger the disease are poorly understood. Although several viruses and seasonal bacterial infections have been associated with HSP, differentiating the specific associations of these pathogens with the onset of HSP remains a challenge due to their overlapping seasonal patterns. […] To analyze the role of seasonal pathogens in the epidemiology of HSP. […] This cohort study comprised an interrupted time-series analysis of patient records from a comprehensive national hospital-based surveillance system. Children younger than 18 years hospitalized for HSP in France between January 1, 2015, and March 31, 2023, were included. […] The main outcomes were the monthly incidence of HSP per 100 000 children, analyzed via a quasi-Poisson regression model, and the estimated percentage of HSP incidence potentially associated with 14 selected common seasonal pathogens over the same period.

• #1 An Investigation of the Relationship between Henoch-Schönlein Purpura and Viral Infection in Korea Using the Health Insurance Database

  https://www.mdpi.com/2077-0383/13/5/1290

  The seasonal distribution shows that HSP occurs more frequently in winter, whereas the lowest onset occurs in summer. […] In our study, 51.3% of all patients with HSP were under 20 years of age, with the highest incidence in the 5–9-year age group. […] Our findings further elucidate which viruses affect different age groups. […] In our study, we analyzed patients with HSP of all ages from 2015 to 2019 in Korea using the HIRA database and viral surveillance data from the KDCA. We found that HPIV, HBoV, HMPV, and rotavirus were associated with the occurrence of HSP in children and adolescents under 20 years of age, and HAdV, HPIV, HRSV, HBoV, HMPV, rotavirus, and norovirus were associated with the occurrence of HSP in those over 20 years of age. […] This study demonstrated the role of infection in the pathogenesis of HSP.

• #1

  https://link.springer.com/article/10.1007/s10067-019-04628-9

  It is unknown whether epidemiological or clinical characteristics of Henoch-Schnlein purpura (HSP) have changed over time. This study aimed at evaluating the epidemiological and clinical changes of HSP during 3 decades. […] Long-term epidemiologic features of HSP were similar to those in other countries. Clinical manifestations of HSP showed a trend towards a less severe clinical phenotype over time in Deajeon, Korea. […] It is unknown whether epidemiological and clinical traits of Henoch-Schnlein purpura (HSP) have changed over time. We reported that clinical manifestations of HSP have changed to milder phenotype through a long-term observation of three decades at a single hospital in Daejeon, South Korea.

• #1 Common Seasonal Pathogens and Epidemiology of Henoch-Schönlein Purpura Among Children

  https://pmc.ncbi.nlm.nih.gov/articles/PMC10998156/

  This study found that significant changes in the incidence of HSP simultaneously with major shifts in circulating pathogens after NPIs for the COVID-19 pandemic indicated that approximately 60% of HSP incidence was potentially associated with pneumococcus and group A streptococcus. […] This unique experimental scenario enabled us to quantify the involvement of seasonal pathogens in triggering pediatric HSP, using the strength of a time-series analysis on a 9790-patient cohort. […] The present study showed a temporal association between the incidence of HSP and the circulation of S pneumoniae and S pyogenes, highlighting the crucial role of streptococcal species in the pathophysiology of HSP. […] Further studies are needed to assess whether specific pneumococcal serotypes may be particularly involved in triggering HSP, which would estimate the potential benefit associated with vaccine prevention and pneumococcal boosters in the general pediatric population. […] In addition to confirming the association between infections and HSP epidemiology, this epidemiologic scenario suggested a key role of pneumococcus and group A streptococcus in pediatric HSP epidemiology.

• #1 Regulatory T and B cells in pediatric Henoch–Schönlein purpura: friends or foes? | Arthritis Research & Therapy | Full Text

  https://arthritis-research.biomedcentral.com/articles/10.1186/s13075-024-03278-w

  HenochSchnlein purpura (HSP) is the most common immunoglobulin A-mediated systemic vasculitis in childhood. The annual incidence varies from country to country, 13 to 20/100,000 children. The prognosis for HSP depends on the presence of renal involvement, occurring in 40% of children. Two to 5% of children with HSP nephritis progress towards renal or end-stage renal failure. […] Many contributing infectious triggering factors have been studiedmainly group A streptococcus infection but also other bacteria and viruses, exposure to drugs or toxic agents, and predisposing genetic factors. […] In adults, age, sex, and ethnicity have emerged as major factors contributing to variations in lymphocyte phenotype composition. […] In our HSP population, there was an increase in the IL-17A serum level and a similar trend for IL-1beta and IL-8 serum levels, as reported earlier. This suggests that the action of Treg and Th3 is insufficient to control inflammation.

• #1 Hematologic and immunological characteristics of Henoch-Schönlein purpura in rat and rabbit models induced with ovalbumin based on type III hypersensitivity | Scientific Reports

  https://www.nature.com/articles/srep08862

  The pathogenesis of HSP is complex and has not been fully understood. […] Reports describing successfully established animal models of HSP are scarce. This study compares the hematologic and immunologic profiles of HSP rat and rabbit models with HSP pediatric patients. […] Taken together, these data indicate that our HSP animal models can mimic human HSP disease in terms of symptoms and histopathological changes. […] In conclusion, the symptoms and pathological and immunological changes in HSP rat and rabbit models were consistent with characteristics in pediatric HSP patients.

• #1 Analysis of 135 Cases of Pediatric Henoch-Schönlein Purpura in Gansu, Northwestern China

  https://brieflands.com/articles/ijp-90663

  Henoch-Schnlein purpura (HSP) is the most widespread systemic small-vessel vasculitis of childhood. Limited information exists about the epidemiology, allergen and laboratory bio-markers reflecting HSP disease phases in Northwestern China. […] To comprehensively evaluate the epidemiology, allergen and laboratory bio-markers reflecting HSP disease phases for the first time in this region. […] The epidemiology of pediatric primary vasculitis varies in different regions and populations. The reported annual incidence is 6 to 30 cases per 100,000 children younger than 17 years for multi-ethnic regions. The annual incidence in China was 14.06 cases per 100,000 children and the ratio of male to female was 1.30:1 to 1.41:1 in different parts of China. […] The epidemiology of pediatric primary vasculitis in Northwestern China is still unclear. The aim of this study was to describe the epidemiology and clinical characteristics of HSP in this region. […] The first report of epidemiologic characteristics of HSP in children in this area enriches the HSP epidemiological data of China.

• #2 IgA Vasculitis (Henoch-Schonlein Purpura): Practice Essentials, Background, Pathophysiology

  https://emedicine.medscape.com/article/984105-overview

  IgAV is the most common vasculitis in childhood. The incidence decreases with age, but in adults the severity increases with age. […] The prevalence of IgAV peaks in children aged 3-10 years, with the mean age at presentation being 6 years, but the condition is also seen in adults. […] It has been reported that IgAV will occur in 10-30 per 100,000 children younger than 17 years will develop IgAV. […] There is a strong ethnic influence on the incidence of the disease, with approximately 70 cases per 100,000 children annually in Asia. […] In the Northern Hemisphere, the disease occurs mostly between November and January. […] IgAV has typically been reported to be more common in males, with a male-to-female ratio ranging from 1.5-2:1, but some studies have found a more equal distribution between the sexes.

• #2 IgA Vasculitis (Henoch-Schonlein Purpura): Practice Essentials, Background, Pathophysiology

  https://emedicine.medscape.com/article/984105-overview

  In the United States, the incidence of IgAV is approximately 14-15 cases per 100,000 population in children, compared with 1-3 cases per 100,000 per year in adults. […] Worldwide, the incidence rates of IgAV in children and adolescents aged 15 years vary widely, ranging from 3.5 per 100,000 persons in Japan to 26.7 per 100,000 persons in Scotland. […] In the United Kingdom overall, the estimated annual incidence of IgAV is 20.4 cases per 100,000 population aged 17 years, with a peak incidence of 70 per 100,000 in children of age four to six years. […] Incidence rates reported elsewhere in Europe are 17.5 per 100,000 in Sweden and 18.6 per 100,000 persons in France. […] Surveys from Taiwan and the Czech Republic report a lower incidence of 10 per 100,000 in children 17 years of age, with a peak incidence at five to seven years of age.

• #2 Henoch-Schönlein Purpura (HSP) | Doctor

  https://patient.info/doctor/henoch-schonlein-purpura-pro

  Henoch-Schnlein purpura (HSP) is a rare condition but is the most common form of systemic vasculitis in children; 90% of cases occur in childhood under the age of 10 years. The peak prevalence is in children aged 4-6 years. It is estimated to affect 10 to 20 per 100,000 children per year. In the UK, the estimated annual incidence is 6-20 cases per 100,000 population. White people are more often affected than other ethnic groups. […] Renal involvement occurs in up to 55% of children with HSP but is usually not serious, with manifestation ranging from microscopic haematuria and mild proteinuria to nephrotic and nephritic syndrome and renal failure. Less than 1% of patients with HSP progress to end-stage kidney disease. The renal prognosis is worse in older children and in adults. […] HSP spontaneously resolves in 94% of children and 89% of adults. However, a subset of patients experience renal involvement that can persist and relapse years later. Long-term prognosis depends on the extent of renal involvement.

• #2 Henoch-Schönlein Purpura in Children: An Updated Review

  https://www.eurekaselect.com/node/181781/4

  Henoch-Schnlein purpura (HSP) is an IgA-mediated systemic small vessel vasculitis with a predilection for the skin, gastrointestinal tract, joints, and kidneys. It is the most common form of systemic vasculitis in children. […] Globally, the incidence of HSP is 10 to 20 cases per 100,000 children per year. Approximately 90% of cases occur in children between 2 and 10 years of age, with a peak incidence at 4 to 7 years. […] Most cases of HSP have an excellent outcome, with renal involvement being the most important prognostic factor in determining morbidity and mortality.

• #2 Gastrointestinal Manifestations of IgA Vasculitis-Henoch-Schönlein Purpura | IntechOpen

  https://www.intechopen.com/chapters/67812

  Immunoglobulin A vasculitis, formerly called Henoch-Schnlein purpura (HSP), is the most common systemic vasculitis in childhood. […] IgA vasculitis is the most common vasculitis for children; it is usually seen in children between 3 and 10 years old (the age peak is 57 years) and very rarely in adults. […] The annual incidence varies greatly, from 13 to 20/100,000 for children to 0.81.8/100,000 for adults. […] Demographic data showed that males are more frequently affected (male-to-female ratio varies from 1.2:1 to 1.8:1). […] The diagnosis is more commonly established in winter and spring and rarely in summer, and this aspect may be explained by the association of this disease with infection factors, while approximately 50% of IgA cases are preceded by an upper respiratory tract infection. […] Clinical features and severity of the disease also differ by aging, being more severe in adults than in children.

• #2 Henoch-Schonlein purpura » Global Autoimmune Institute

  https://www.autoimmuneinstitute.org/autoimmune-resources/autoimmune-diseases-list/henoch-schonlein-purpura/

  HSP, also known as IgA vasculitis, is characterized by inflammation of the small blood vessels located in the skin, joints, intestines, and kidneys, sometimes accompanied by bleeding. […] Those between the ages of 4 and 6 are most commonly affected. Males tend to be more commonly affected by HSP than females. African American children are less commonly affected by the condition than white or Asian children. Environmental triggers include colds, chickenpox, strep throat, measles, and hepatitis. Many recorded cases of HSP have followed upper respiratory infections. […] IgA vasculitis update: Epidemiology, pathogenesis, and biomarkers (2022)

• #2 Henoch-Schönlein Purpura | 5-Minute Clinical Consult

  https://www.unboundmedicine.com/5minute/view/5-Minute-Clinical-Consult/1688445/all/Henoch_Sch%C3%B6nlein_Purpura

  Henoch-Schnlein purpura (HSP) is a nonthrombocytopenic, predominantly IgA-mediated, small vessel vasculitis that affects multiple organ systems and occurs in both children and adults. […] Annual incidence: estimated 29.9/100,000 children and 0.1 to 1.8/100,000 adults. […] Peak incidence: age 4 to 6 years; 90% of patients with HSP are 10 years of age; however, has been reported in patients aged 6 months to 75 years old. […] Gender: Male-to-female ratio is between 1.2:1 and 1.8:1. […] Race/ethnicity: most common in Caucasians and Asians; less common among African Americans. […] Annual prevalence: 10 to 22/100,000 persons; more common in fall and winter.

• #2 An Investigation of the Relationship between Henoch-Schönlein Purpura and Viral Infection in Korea Using the Health Insurance Database

  https://www.mdpi.com/2077-0383/13/5/1290

  The seasonal distribution shows that HSP occurs more frequently in winter, whereas the lowest onset occurs in summer. […] In our study, 51.3% of all patients with HSP were under 20 years of age, with the highest incidence in the 5–9-year age group. […] Our findings further elucidate which viruses affect different age groups. […] In our study, we analyzed patients with HSP of all ages from 2015 to 2019 in Korea using the HIRA database and viral surveillance data from the KDCA. We found that HPIV, HBoV, HMPV, and rotavirus were associated with the occurrence of HSP in children and adolescents under 20 years of age, and HAdV, HPIV, HRSV, HBoV, HMPV, rotavirus, and norovirus were associated with the occurrence of HSP in those over 20 years of age. […] This study demonstrated the role of infection in the pathogenesis of HSP.

• #2 Common Seasonal Pathogens and Epidemiology of Henoch-Schönlein Purpura Among Children

  https://pmc.ncbi.nlm.nih.gov/articles/PMC10998156/

  This study found that significant changes in the incidence of HSP simultaneously with major shifts in circulating pathogens after NPIs for the COVID-19 pandemic indicated that approximately 60% of HSP incidence was potentially associated with pneumococcus and group A streptococcus. […] This unique experimental scenario enabled us to quantify the involvement of seasonal pathogens in triggering pediatric HSP, using the strength of a time-series analysis on a 9790-patient cohort. […] The present study showed a temporal association between the incidence of HSP and the circulation of S pneumoniae and S pyogenes, highlighting the crucial role of streptococcal species in the pathophysiology of HSP. […] Further studies are needed to assess whether specific pneumococcal serotypes may be particularly involved in triggering HSP, which would estimate the potential benefit associated with vaccine prevention and pneumococcal boosters in the general pediatric population. […] In addition to confirming the association between infections and HSP epidemiology, this epidemiologic scenario suggested a key role of pneumococcus and group A streptococcus in pediatric HSP epidemiology.

• #2 COVID-19 and Rheumatology

  https://www.healio.com/news/rheumatology/20240506/henochschnlein-purpura-incidence-fell-rose-with-covid19-protective-measures

  The incidence of Henoch-Schnlein purpura significantly decreased with the implementation of COVID-19 protective measures. […] The study additionally suggests that approximately 60% of Henoch-Schnlein purpura (HSP) incidence is associated with pneumococcus and group A streptococcus. […] According to the researchers, HSP incidence decreased significantly after NPIs against COVID-19 were implemented in March 2020 (53.6%; 95% CI, 66.6% to 40.6%), and then increased significantly after their relaxation in April 2021 (37.2%; 95% CI, 28%-46.3%). […] In addition to confirming the association between infections and HSP epidemiology, this epidemiologic scenario suggested a key role of pneumococcus and group A streptococcus in pediatric HSP epidemiology.

• #2 Demographic, Epidemiologic and Clinical Analyses of Paediatric Patients Hospitalized with Henoch-Schonlein Purpura: A Retrospective Study – The Journal of Pediatric Research

  https://jpedres.org/articles/demographic-epidemiologic-and-clinical-analyses-of-paediatric-patients-hospitalized-with-henoch-schonlein-purpura-a-retrospective-study/doi/jpr.galenos.2020.93695

  Renal involvement occurs in 40-50% of patients generally as microscopic haematuria and/or proteinuria. […] The manifestation of nephrotic syndrome or renal failure associated with renal involvement in HSP may manifest in a small percentage of patients. […] Although the dominant involvements of HSP are skin, joint, gastrointestinal, and kidney; infrequent and unusual system manifestations including cerebral vasculitis, scrotal or testicular haemorrhage, and interstitial pulmonary haemorrhage have been described. […] This index study presents a descriptive analyse of paediatric patients in Ege University Childrens hospital during a 6-year-period.

• #2 Incidence and risk factors for recurrent Henoch-Schönlein purpura in children from a 16-year nationwide database | Pediatric Rheumatology | Full Text

  https://ped-rheum.biomedcentral.com/articles/10.1186/s12969-018-0247-8

  The recurrence rate of Henoch-Schnlein purpura (HSP) is 2.7%30%, with varied average intervals between the first and second episodes. Few studies have explored the incidence and risk factors for recurrent HSP. […] We used a 16-year nationwide database to analyze the incidence of recurrent HSP. Patients with HSP were identified, and risk factors for recurrent HSP were explored. […] The annual incidence of recurrent HSP was low. However, children who had underlying allergic rhinitis, presented with renal involvement, and received steroid treatment for 10 days should be notified regarding the possibility of recurrence. […] The incidence of HSP in children is approximately 622 per 100,000 person-years, which is higher than that in adult (3.414.3 per 100,000 person years). […] The prognosis of HSP is generally good, but recurrence is common among children (recurrence rate, 2.7%66.2%).

• #2 Incidence and risk factors for recurrent Henoch-Schönlein purpura in children from a 16-year nationwide database | Pediatric Rheumatology | Full Text

  https://ped-rheum.biomedcentral.com/articles/10.1186/s12969-018-0247-8

  The recurrence rate (16.3%) in our study was within the range described by a previous study (2.7%66.2%). […] Our finding that allergic rhinitis was an independent risk factor for HSP was in line with studies reporting an increased risk of HSP in atopic children. […] Our study showed a significantly increased association between steroid use for 10 days regardless of early initiation and the risk of recurrence. […] The average duration between the first and second HSP episodes was 9.2 months. […] For the early detection of recurrence, it may be worth considering following up patients with the first HSP episode for at least 9.2 months and those with a second HSP episode for another 6.4 months.

• #2 Henoch Schönlein Purpura (HSP)

  https://rheumatology.org/patients/henoch-schonlein-purpura-hsp

  Henoch Schönlein Purpura (HSP) is a type of vasculitis, which means inflammation of the blood vessels. […] In North America, HSP is the most common form of vasculitis in children. It is most common in ages 3 to 15 years and is more common in boys than girls. […] One of the most important parts of HSP management is monitoring for kidney disease. Children with worsening urinary findings like high blood pressure or rising creatinine (a blood marker of kidney function) should be seen by a nephrologist (kidney doctor). […] Urine screening and monitoring of the blood pressure is recommended for at least 6 months after the initial diagnosis, so it is important to follow the screening instructions provided by your doctor.

• #2 Henoch-Schonlein Purpura | Children’s Hospital of Philadelphia

  https://www.chop.edu/conditions-diseases/henoch-schonlein-purpura

  Henoch-Schönlein purpura (HSP) is a form of vasculitis, a condition that involves inflammation of the blood vessels. It can affect any organ of the body. […] HSP is the most common form of vasculitis in childhood and affects about 20 in 100,000 children. It occurs most commonly in children ages 2-6, although it can occur at any age. […] The most serious potential complication of Henoch-Schönlein purpura is kidney damage — which can be irreversible. For this reason, children with HSP should be carefully monitored for the first 6 months after diagnosis. Testing should include regular blood pressure checks and urine analysis. […] About a third of children with HSP will experience a recurrence of symptoms within the first year after disease onset. In most cases, the recurrence is less severe and lasts a shorter period of time than the initial onset of symptoms. […] Women with a history of Henoch-Schönlein purpura, regardless of prior kidney involvement, are at increased risk of developing preeclampsia during pregnancy. […] In rare cases, HSP can lead to permanent damage to the kidneys, which may require life-long management by a nephrologist.

• #2 Henoch-Schönlein Purpura : Johns Hopkins Vasculitis CenterFacebookTwitterYouTube

  https://www.hopkinsvasculitis.org/types-vasculitis/henochschnlein-purpura/

  HSP is the most common form of vasculitis in children, with an annual incidence on the order of 140 cases/million persons. The mean age of patients with HSP is 5.9 years. […] More than 90% of cases occur in children. The disease usually resolves within a few weeks. However, adult cases are sometimes more difficult. […] HSP patients who experience this symptom should be followed more closely, with regular testing of their urine for blood and protein. Recurrences, found in 33% of patients, usually develop within the first few months after resolution of the first bout.

• #2 Regulatory T and B cells in pediatric Henoch–Schönlein purpura: friends or foes? | Arthritis Research & Therapy | Full Text

  https://arthritis-research.biomedcentral.com/articles/10.1186/s13075-024-03278-w

  In our population, Breg percentages tended to be lower in HSP nephritis compared to HSP without kidney involvement. […] A striking observation in our study is the paradoxical effect of patients Tregs on IgA-secreting cells in vitro. […] Based on these results, we propose the following regulatory pattern for HSP: Following immune stimulation by a potential viral or bacterial infection, the antigen-presenting cells activate the Th3 cells which, by secreting TGF-beta, lead to IgA overproduction by B cell lineage. The Tregs which are not deficient try to dampen the inflammation and, surprisingly, IgA production during the acute phase. […] To summarize, we observed an increase in Tregs and Th3 cells apparently failing to inhibit immune activation. Remarkably, Breg cells are fewer in the HSP population with nephropathy. Finally, we unveiled the unusual negative effect of Tregs on IgA production which is also insufficient.

• #3 Henoch-Schönlein Purpura (HSP) | Doctor

  https://patient.info/doctor/henoch-schonlein-purpura-pro

  Henoch-Schnlein purpura (HSP) is a rare condition but is the most common form of systemic vasculitis in children; 90% of cases occur in childhood under the age of 10 years. The peak prevalence is in children aged 4-6 years. It is estimated to affect 10 to 20 per 100,000 children per year. In the UK, the estimated annual incidence is 6-20 cases per 100,000 population. White people are more often affected than other ethnic groups. […] Renal involvement occurs in up to 55% of children with HSP but is usually not serious, with manifestation ranging from microscopic haematuria and mild proteinuria to nephrotic and nephritic syndrome and renal failure. Less than 1% of patients with HSP progress to end-stage kidney disease. The renal prognosis is worse in older children and in adults. […] HSP spontaneously resolves in 94% of children and 89% of adults. However, a subset of patients experience renal involvement that can persist and relapse years later. Long-term prognosis depends on the extent of renal involvement.

• #3 IgA Vasculitis (Henoch–Schönlein Purpura): An Update on Treatment

  https://www.mdpi.com/2077-0383/13/21/6621

  Henoch–Schönlein purpura (HSP) is a systemic small-vessel vasculitis whose main anatomopathological feature is the deposition of IgA1-dominant immune complexes (ICs) in the affected tissues, and its nomenclature has been recently changed to immunoglobulin A vasculitis (IgAV) in the latest consensual classification of vasculitis. An annual incidence of IgAV in children of around 3 to 27 cases per 100,000 cases has been reported, representing the most frequent vasculitis in childhood. […] In Northwestern Spain, an epidemiological study conducted over 20 years found a higher prevalence of IgAV in children during fall and winter, and reported an annual incidence rate of 10.45 per 100,000 cases in children under 14 years of age. […] Additionally, the frequency of IgAV in adults is about 10 times lower than in children, with an annual incidence of 0.1 to 14 per 100,000 people. […] The frequency of glomerulonephritis (referred to as IgAV nephritis) in adults is higher than in children and tends to present more severely, with around 10–30% of those affected eventually progressing to end-stage renal disease.

• #3 IgA Vasculitis (Henoch-Schonlein Purpura): Practice Essentials, Background, Pathophysiology

  https://emedicine.medscape.com/article/984105-overview

  In the United States, the incidence of IgAV is approximately 14-15 cases per 100,000 population in children, compared with 1-3 cases per 100,000 per year in adults. […] Worldwide, the incidence rates of IgAV in children and adolescents aged 15 years vary widely, ranging from 3.5 per 100,000 persons in Japan to 26.7 per 100,000 persons in Scotland. […] In the United Kingdom overall, the estimated annual incidence of IgAV is 20.4 cases per 100,000 population aged 17 years, with a peak incidence of 70 per 100,000 in children of age four to six years. […] Incidence rates reported elsewhere in Europe are 17.5 per 100,000 in Sweden and 18.6 per 100,000 persons in France. […] Surveys from Taiwan and the Czech Republic report a lower incidence of 10 per 100,000 in children 17 years of age, with a peak incidence at five to seven years of age.

• #3 Henoch-Schönlein Purpura | 5-Minute Clinical Consult

  https://www.unboundmedicine.com/5minute/view/5-Minute-Clinical-Consult/1688445/all/Henoch_Sch%C3%B6nlein_Purpura

  Henoch-Schnlein purpura (HSP) is a nonthrombocytopenic, predominantly IgA-mediated, small vessel vasculitis that affects multiple organ systems and occurs in both children and adults. […] Annual incidence: estimated 29.9/100,000 children and 0.1 to 1.8/100,000 adults. […] Peak incidence: age 4 to 6 years; 90% of patients with HSP are 10 years of age; however, has been reported in patients aged 6 months to 75 years old. […] Gender: Male-to-female ratio is between 1.2:1 and 1.8:1. […] Race/ethnicity: most common in Caucasians and Asians; less common among African Americans. […] Annual prevalence: 10 to 22/100,000 persons; more common in fall and winter.

• #3 :: PGHN :: Pediatric Gastroenterology, Hepatology & Nutrition

  https://pghn.org/DOIx.php?id=10.5223/pghn.2016.19.3.175

  The peak incidence of HSP was in the winter (33.0%) and lowest in the summer (11.8%), which is in keeping with findings from previous studies. […] The rate of renal involvement was relatively low in Korea compared to that of other countries. […] In this study, joint symptoms were more frequently observed in younger children. […] In this study, clinical manifestations were assessed by diving patients into two groups based on a reference age of 7 years. […] In this study, there was an association between GI symptoms and scrotal involvement, but no significant association was observed between scrotal involvement and renal involvement. […] In children with HSP, the incidence of renal involvement and nephrotic syndrome is higher in those presenting at an older age, and in those patients with severe abdominal pain or GI hemorrhage.

• #3 COVID-19 and Rheumatology

  https://www.healio.com/news/rheumatology/20240506/henochschnlein-purpura-incidence-fell-rose-with-covid19-protective-measures

  The incidence of Henoch-Schnlein purpura significantly decreased with the implementation of COVID-19 protective measures. […] The study additionally suggests that approximately 60% of Henoch-Schnlein purpura (HSP) incidence is associated with pneumococcus and group A streptococcus. […] According to the researchers, HSP incidence decreased significantly after NPIs against COVID-19 were implemented in March 2020 (53.6%; 95% CI, 66.6% to 40.6%), and then increased significantly after their relaxation in April 2021 (37.2%; 95% CI, 28%-46.3%). […] In addition to confirming the association between infections and HSP epidemiology, this epidemiologic scenario suggested a key role of pneumococcus and group A streptococcus in pediatric HSP epidemiology.

• #3 Henoch Schönlein Purpura (HSP)

  https://rheumatology.org/patients/henoch-schonlein-purpura-hsp

  Henoch Schönlein Purpura (HSP) is a type of vasculitis, which means inflammation of the blood vessels. […] In North America, HSP is the most common form of vasculitis in children. It is most common in ages 3 to 15 years and is more common in boys than girls. […] One of the most important parts of HSP management is monitoring for kidney disease. Children with worsening urinary findings like high blood pressure or rising creatinine (a blood marker of kidney function) should be seen by a nephrologist (kidney doctor). […] Urine screening and monitoring of the blood pressure is recommended for at least 6 months after the initial diagnosis, so it is important to follow the screening instructions provided by your doctor.

• #4 IgA Vasculitis (Henoch-Schonlein Purpura): Practice Essentials, Background, Pathophysiology

  https://emedicine.medscape.com/article/984105-overview

  In the United States, the incidence of IgAV is approximately 14-15 cases per 100,000 population in children, compared with 1-3 cases per 100,000 per year in adults. […] Worldwide, the incidence rates of IgAV in children and adolescents aged 15 years vary widely, ranging from 3.5 per 100,000 persons in Japan to 26.7 per 100,000 persons in Scotland. […] In the United Kingdom overall, the estimated annual incidence of IgAV is 20.4 cases per 100,000 population aged 17 years, with a peak incidence of 70 per 100,000 in children of age four to six years. […] Incidence rates reported elsewhere in Europe are 17.5 per 100,000 in Sweden and 18.6 per 100,000 persons in France. […] Surveys from Taiwan and the Czech Republic report a lower incidence of 10 per 100,000 in children 17 years of age, with a peak incidence at five to seven years of age.

• #5 IgA Vasculitis (Henoch-Schonlein Purpura): Practice Essentials, Background, Pathophysiology

  https://emedicine.medscape.com/article/984105-overview

  In the United States, the incidence of IgAV is approximately 14-15 cases per 100,000 population in children, compared with 1-3 cases per 100,000 per year in adults. […] Worldwide, the incidence rates of IgAV in children and adolescents aged 15 years vary widely, ranging from 3.5 per 100,000 persons in Japan to 26.7 per 100,000 persons in Scotland. […] In the United Kingdom overall, the estimated annual incidence of IgAV is 20.4 cases per 100,000 population aged 17 years, with a peak incidence of 70 per 100,000 in children of age four to six years. […] Incidence rates reported elsewhere in Europe are 17.5 per 100,000 in Sweden and 18.6 per 100,000 persons in France. […] Surveys from Taiwan and the Czech Republic report a lower incidence of 10 per 100,000 in children 17 years of age, with a peak incidence at five to seven years of age.

• #6 IgA Vasculitis (Henoch-Schonlein Purpura): Practice Essentials, Background, Pathophysiology

  https://emedicine.medscape.com/article/984105-overview

  In the United States, the incidence of IgAV is approximately 14-15 cases per 100,000 population in children, compared with 1-3 cases per 100,000 per year in adults. […] Worldwide, the incidence rates of IgAV in children and adolescents aged 15 years vary widely, ranging from 3.5 per 100,000 persons in Japan to 26.7 per 100,000 persons in Scotland. […] In the United Kingdom overall, the estimated annual incidence of IgAV is 20.4 cases per 100,000 population aged 17 years, with a peak incidence of 70 per 100,000 in children of age four to six years. […] Incidence rates reported elsewhere in Europe are 17.5 per 100,000 in Sweden and 18.6 per 100,000 persons in France. […] Surveys from Taiwan and the Czech Republic report a lower incidence of 10 per 100,000 in children 17 years of age, with a peak incidence at five to seven years of age.

• #7 IgA Vasculitis (Henoch-Schonlein Purpura): Practice Essentials, Background, Pathophysiology

  https://emedicine.medscape.com/article/984105-overview

  In the United States, the incidence of IgAV is approximately 14-15 cases per 100,000 population in children, compared with 1-3 cases per 100,000 per year in adults. […] Worldwide, the incidence rates of IgAV in children and adolescents aged 15 years vary widely, ranging from 3.5 per 100,000 persons in Japan to 26.7 per 100,000 persons in Scotland. […] In the United Kingdom overall, the estimated annual incidence of IgAV is 20.4 cases per 100,000 population aged 17 years, with a peak incidence of 70 per 100,000 in children of age four to six years. […] Incidence rates reported elsewhere in Europe are 17.5 per 100,000 in Sweden and 18.6 per 100,000 persons in France. […] Surveys from Taiwan and the Czech Republic report a lower incidence of 10 per 100,000 in children 17 years of age, with a peak incidence at five to seven years of age.

Zobacz więcej