Materiały źródłowe

• #1 Pediculosis – StatPearls – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK470343/

  Patients frequently present with pruritis, typically from an immune-mediated hypersensitivity reaction. It may take 2 to 6 weeks to develop symptoms after the first exposure, while pruritis can develop 1 or 2 days after re-exposure. […] The head louse is an obligate parasite that spends its entire life on the human host. Head lice feed exclusively on blood. Lice are unable to jump or fly, and transmission requires close contact. Transmission of head lice is thought to occur by head-to-head contact, sharing of headgear, or other direct contact with fomites (inanimate objects that harbor the organism, such as movie seats). […] Pharmacologic treatment of lice focuses on 2 mechanisms: neurotoxicity resulting in paralysis of the louse and suffocation from topical application. […] Permethrin affects sodium transport across neuronal membranes, causing respiratory paralysis in arthropods.

• #2 Pediculosis and Pthiriasis (Lice Infestation): Background, Pathophysiology, Etiology

  https://emedicine.medscape.com/article/225013-overview

  Lice are ectoparasites that live on the body. Lice feed on human blood after piercing the skin and injecting saliva, which may cause pruritus due to an allergic reaction. […] Lice are blood-sucking insects. Human lice have small anterior mouthparts with 6 hooklets that aid their attachment to human skin during feeding. The sucking mouthparts retract into the head when the lice are not feeding. In general, lice feed approximately 5 times per day. […] The adult female louse lays eggs, called nits, and glues them at the base of the hair shaft. Nits are placed within 1-2 mm of the scalp, where the temperature is optimal for incubation. The female head louse lays as many as 10 eggs per 24 hours, usually at night. […] Nits hatch in about 8-9 days if they are kept near body temperature and mature in another 9-12 days.

• #3 Head louse – Wikipedia

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

  The head louse (Pediculus humanus capitis) is an obligate ectoparasite of humans. Head lice are wingless insects that spend their entire lives on the human scalp and feed exclusively on human blood. […] Lice differ from other hematophagic ectoparasites such as fleas in spending their entire lifecycle on a host. […] Like other members of the Anoplura, head louse mouthparts are highly adapted for piercing the skin and sucking blood. […] All stages except eggs are blood-feeders and bite the skin four to five times daily to feed. They inject saliva which contains an anticoagulant and suck blood. […] Head lice reproduce sexually, and copulation is necessary for the female to produce fertile eggs. Parthenogenesis, the production of viable offspring by virgin females, does not occur in Pediculus humanus. […] During its lifespan of 4 weeks a female louse lays 50-150 eggs. Eggs hatch within 6-9 days, each nymphal stage lasts for 4-5 days and accordingly the period from egg to adults lasts for 18-24 days.

• #4 Pediculosis – Ectoparasitic Infestations – Parasitic Diseases – Infectious Diseases – Diseases – McMaster Textbook of Internal Medicine

  https://empendium.com/mcmtextbook/chapter/B31.II.18.84.4.3.

  1. Pathogenesis: Lice pierce the hosts skin to feed on blood. Ich ich saliva irritates the skin and causes pruritus and lesions. Each louse pierces the hosts skin 5 times a day. Louse saliva contains compounds with various biologic properties, including anticoagulative and local anesthetic effects. Proteins from louse saliva can cause allergic reactions, on average within 3 to 4 weeks after the bite, leading to persistent severe pruritus.

• #5 Head lice. Pediculosis capitis

  https://dermnetnz.org/topics/head-lice

  Head lice are small, wingless insects that infest the human scalp. They are the most common of the 3 human lice species. […] The head louse, Pediculus humanus capitis, is an ectoparasite that feeds on human blood. It is 23 mm in length and has a flattened, elongated, grey coloured body that becomes reddish after feeding. The louse clings to the hair shaft by its 6 claws and rapidly moves from hair to hair. […] Lice inject anticoagulant saliva into a person’s scalp to suck up the blood up to five times a day. They die within one to two days away from the scalp if they are unable to feed. […] The louse nymph reaches full maturity around 10 days after hatching and the cycle begins again. An adult louse survives on the scalp for about one month, and away from the scalp for up to 48 hours.

• #6 Pediculosis and Pthiriasis (Lice Infestation): Background, Pathophysiology, Etiology

  https://emedicine.medscape.com/article/225013-overview

  Lice are ectoparasites that live on the body. Lice feed on human blood after piercing the skin and injecting saliva, which may cause pruritus due to an allergic reaction. […] Lice are blood-sucking insects. Human lice have small anterior mouthparts with 6 hooklets that aid their attachment to human skin during feeding. The sucking mouthparts retract into the head when the lice are not feeding. In general, lice feed approximately 5 times per day. […] The adult female louse lays eggs, called nits, and glues them at the base of the hair shaft. Nits are placed within 1-2 mm of the scalp, where the temperature is optimal for incubation. The female head louse lays as many as 10 eggs per 24 hours, usually at night. […] Nits hatch in about 8-9 days if they are kept near body temperature and mature in another 9-12 days.

• #7 Pediculosis – Ectoparasitic Infestations – Parasitic Diseases – Infectious Diseases – Diseases – McMaster Textbook of Internal Medicine

  https://empendium.com/mcmtextbook/chapter/B31.II.18.84.4.3.

  1. Pathogenesis: Lice pierce the hosts skin to feed on blood. Ich ich saliva irritates the skin and causes pruritus and lesions. Each louse pierces the hosts skin 5 times a day. Louse saliva contains compounds with various biologic properties, including anticoagulative and local anesthetic effects. Proteins from louse saliva can cause allergic reactions, on average within 3 to 4 weeks after the bite, leading to persistent severe pruritus.

• #8 Pediculosis capitis: An update – Indian Journal of Dermatology, Venereology and Leprology

  https://ijdvl.com/pediculosis-capitis-an-update/

  Head louse infestation, or pediculosis capitis, caused by Pediculus humanus var. capitis, is a common health concern in pediatric age group. An itching of the scalp is the chief symptom, whereas presence of viable nits confirms the diagnosis of head louse infestation. […] The louse chiefly resides in close contact to human scalp and takes blood meals, which is postulated to be 6 times per day. With each blood meal, a minute quantity of louse saliva gets inoculated into the scalp skin, and the host becomes sensitized to louse antigen and fecal matter eliciting an inflammatory response leading to scratching and secondary impetignization. […] After successful landing on scalp skin, head louse takes a blood meal (hematophagia) usually 4 to 5 times per day. While taking a blood meal, lice injects its saliva through the scalp skin to prevent clotting of blood, thereby maintaining the fluidity for an easy sucking. Chronic and heavy lice infestation can rarely lead to anemia, especially in rural females who are already suffering from iron deficiency anemia.

• #9 Pediculosis – Ectoparasitic Infestations – Parasitic Diseases – Infectious Diseases – Diseases – McMaster Textbook of Internal Medicine

  https://empendium.com/mcmtextbook/chapter/B31.II.18.84.4.3.

  1. Pathogenesis: Lice pierce the hosts skin to feed on blood. Ich ich saliva irritates the skin and causes pruritus and lesions. Each louse pierces the hosts skin 5 times a day. Louse saliva contains compounds with various biologic properties, including anticoagulative and local anesthetic effects. Proteins from louse saliva can cause allergic reactions, on average within 3 to 4 weeks after the bite, leading to persistent severe pruritus.

• #10

  https://fpnotebook.com/Derm/Parasite/Lc.htm

  Lice feed on blood […] Typical feeding every 3-6 hours […] Survival 15-20 hours without a blood meal […] Survival beyond 48 hours without blood meal is rare […] Lice cannot jump or fly […] Close contact person to person transmission […] Requires direct head contact […] Shared inanimate objects (nits survive 2 days) […] Transmitted by fomites or head to head contact […] Permethrin 1% (Nix) – OTC (effective in 90% of cases) […] Mechanism: Neurotoxic to lice […] Pyrethrins 0.3% with Piperonyl Butoxide 4% Shampoo (Rid) […] Mechanism: Neurotoxic to lice […] FDA approved use for Lice (prescription only) […] Mechanism: Neurotoxic to lice […] FDA approved in 2022 […] Mechanism: Suffocates lice […] Mechanism: Suffocates lice […] Mechanism: Dissolves lice exoskeleton

• #11 About Lice and Their Control | US EPA

  https://www.epa.gov/ipm/about-lice-and-their-control

  Head lice are tiny parasites that attach to human head hair and feed on blood through the skin. […] Head lice (Pediculus P. humanus) are one of 500 species of „sucking louse” that feed on mammalian blood, but one of only three species that feed specifically on human blood. […] Nits will not live unless they get a meal of human blood as soon as they hatch. […] Lice cannot live without human blood for more than 24 hours.

• #12 Pediculosis – StatPearls – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK470343/

  Patients frequently present with pruritis, typically from an immune-mediated hypersensitivity reaction. It may take 2 to 6 weeks to develop symptoms after the first exposure, while pruritis can develop 1 or 2 days after re-exposure. […] The head louse is an obligate parasite that spends its entire life on the human host. Head lice feed exclusively on blood. Lice are unable to jump or fly, and transmission requires close contact. Transmission of head lice is thought to occur by head-to-head contact, sharing of headgear, or other direct contact with fomites (inanimate objects that harbor the organism, such as movie seats). […] Pharmacologic treatment of lice focuses on 2 mechanisms: neurotoxicity resulting in paralysis of the louse and suffocation from topical application. […] Permethrin affects sodium transport across neuronal membranes, causing respiratory paralysis in arthropods.

• #13 Pediculosis – StatPearls – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK470343/

  Patients frequently present with pruritis, typically from an immune-mediated hypersensitivity reaction. It may take 2 to 6 weeks to develop symptoms after the first exposure, while pruritis can develop 1 or 2 days after re-exposure. […] The head louse is an obligate parasite that spends its entire life on the human host. Head lice feed exclusively on blood. Lice are unable to jump or fly, and transmission requires close contact. Transmission of head lice is thought to occur by head-to-head contact, sharing of headgear, or other direct contact with fomites (inanimate objects that harbor the organism, such as movie seats). […] Pharmacologic treatment of lice focuses on 2 mechanisms: neurotoxicity resulting in paralysis of the louse and suffocation from topical application. […] Permethrin affects sodium transport across neuronal membranes, causing respiratory paralysis in arthropods.

• #14 Lice and Scabies: Treatment Update | AAFP

  https://www.aafp.org/pubs/afp/issues/2019/0515/p635.html

  Pediculosis and scabies are caused by ectoparasites. Pruritus is the most common presenting symptom with both conditions. The pruritus associated with pediculosis is a delayed hypersensitivity reaction, which may take four to six weeks to develop after the first exposure, with future exposures resulting in pruritus within one to two days. Pharmacologic treatment of head lice infestation is focused on three general mechanisms: neurotoxicity resulting in paralysis of the lice (insecticidal treatments), suffocation via coating the lice, or dissolution of the wax covering on the exoskeleton. Insecticidal agents that are neurotoxic to lice include permethrin 1% lotion or shampoo (Nix), pyrethrins 0.3%/piperonyl butoxide 4% shampoo (Rid), malathion 0.5% lotion (Ovide), spinosad 0.9% suspension (Natroba), ivermectin 0.5% lotion (Sklice), and oral ivermectin (Stromectol; off-label use). Noninsecticidal agents that rely on suffocation or exoskeleton dissolution include benzyl alcohol 5% lotion (Ulesfia), dimethicone solution (Nix Ultra, Lice MD), and isopropyl myristate solution (Resultz; approved by the U.S. Food and Drug Administration in May 2017 but not yet marketed in the United States). A key to formulating an effective treatment regimen is recognizing the effectiveness of available treatments in destroying viable eggs because this dictates if retreatment is necessary. Resistance to permethrin and pyrethrins/piperonyl butoxide can be significant, although the geographic distribution of resistant lice is not well-known.

• #15 Pediculosis – Ectoparasitic Infestations – Parasitic Diseases – Infectious Diseases – Diseases – McMaster Textbook of Internal Medicine

  https://empendium.com/mcmtextbook/chapter/B31.II.18.84.4.3.

  1. Pathogenesis: Lice pierce the hosts skin to feed on blood. Ich ich saliva irritates the skin and causes pruritus and lesions. Each louse pierces the hosts skin 5 times a day. Louse saliva contains compounds with various biologic properties, including anticoagulative and local anesthetic effects. Proteins from louse saliva can cause allergic reactions, on average within 3 to 4 weeks after the bite, leading to persistent severe pruritus.

• #16 Pediculosis – StatPearls – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK470343/

  Malathion 0.5% is an organophosphate cholinesterase inhibitor that causes respiratory paralysis in arthropods. […] Lindane 1% is an organochloride that kills lice by respiratory paralysis. […] Benzyl alcohol 5% lotion was approved in 2009 as a topical suffocation treatment that prevents lice from closing their respiratory spiracles. […] Spinosad 0.9% is a topical pediculicidal agent that was approved in 2011. It works by provoking hyperexcitation, causing death by paralysis. […] Topical ivermectin 0.5% lotion increases chloride in muscle cells, causing hyperpolarization and paralysis. […] The only currently used oral treatment for pediculosis is ivermectin. Ivermectin also has a risk of neurotoxicity. […] Body lice are eradicated through proper hygiene, laundering, or insecticide application to affected clothing. […] Frequent lice treatment is also known to cause severe itching, which can lead to skin breakdown and secondary bacterial infections.

• #17 Head lice – Symptoms & causes – Mayo Clinic

  https://www.mayoclinic.org/diseases-conditions/head-lice/symptoms-causes/syc-20356180

  Head lice are spread primarily by direct head-to-head contact. So the risk of spreading head lice is greatest among children who play or go to school together. In the United States, cases of head lice most often occur in children in preschool through elementary school. […] If your child scratches an itchy scalp due to head lice, it’s possible for the skin to break and develop an infection.

• #18 Pediculosis capitis pathophysiology – wikidoc

  https://www.wikidoc.org/index.php/Pediculosis_capitis_pathophysiology

  Life cycle of Head lice. The life cycle of the head louse has three stages: egg, nymph, and adult. Eggs: Nits are head lice eggs. They are hard to see and are often confused for dandruff or hair spray droplets. Nits are laid by the adult female and are cemented at the base of the hair shaft nearest the scalp. They are 0.8 mm by 0.3 mm, oval and usually yellow to white. Nits take about 1 week to hatch (range 6 to 9 days). Viable eggs are usually located within 6 mm of the scalp. […] Nymphs: The egg hatches to release a nymph. The nit shell then becomes a more visible dull yellow and remains attached to the hair shaft. The nymph looks like an adult head louse, but is about the size of a pinhead. Nymphs mature after three molts and become adults about 7 days after hatching. […] Adults: The adult louse is about the size of a sesame seed, has 6 legs (each with claws), and is tan to grayish-white. In persons with dark hair, the adult louse will appear darker. Females are usually larger than males and can lay up to 8 nits per day. Adult lice can live up to 30 days on a persons head. To live, adult lice need to feed on blood several times daily. Without blood meals, the louse will die within 1 to 2 days off the host.

• #19 Pediculosis and Pthiriasis (Lice Infestation): Background, Pathophysiology, Etiology

  https://emedicine.medscape.com/article/225013-overview

  Lice are ectoparasites that live on the body. Lice feed on human blood after piercing the skin and injecting saliva, which may cause pruritus due to an allergic reaction. […] Lice are blood-sucking insects. Human lice have small anterior mouthparts with 6 hooklets that aid their attachment to human skin during feeding. The sucking mouthparts retract into the head when the lice are not feeding. In general, lice feed approximately 5 times per day. […] The adult female louse lays eggs, called nits, and glues them at the base of the hair shaft. Nits are placed within 1-2 mm of the scalp, where the temperature is optimal for incubation. The female head louse lays as many as 10 eggs per 24 hours, usually at night. […] Nits hatch in about 8-9 days if they are kept near body temperature and mature in another 9-12 days.

• #20 Pediculosis and Pthiriasis (Lice Infestation): Background, Pathophysiology, Etiology

  https://emedicine.medscape.com/article/225013-overview

  Lice are ectoparasites that live on the body. Lice feed on human blood after piercing the skin and injecting saliva, which may cause pruritus due to an allergic reaction. […] Lice are blood-sucking insects. Human lice have small anterior mouthparts with 6 hooklets that aid their attachment to human skin during feeding. The sucking mouthparts retract into the head when the lice are not feeding. In general, lice feed approximately 5 times per day. […] The adult female louse lays eggs, called nits, and glues them at the base of the hair shaft. Nits are placed within 1-2 mm of the scalp, where the temperature is optimal for incubation. The female head louse lays as many as 10 eggs per 24 hours, usually at night. […] Nits hatch in about 8-9 days if they are kept near body temperature and mature in another 9-12 days.

• #21 Pediculosis and Pthiriasis (Lice Infestation): Background, Pathophysiology, Etiology

  https://emedicine.medscape.com/article/225013-overview

  Lice are ectoparasites that live on the body. Lice feed on human blood after piercing the skin and injecting saliva, which may cause pruritus due to an allergic reaction. […] Lice are blood-sucking insects. Human lice have small anterior mouthparts with 6 hooklets that aid their attachment to human skin during feeding. The sucking mouthparts retract into the head when the lice are not feeding. In general, lice feed approximately 5 times per day. […] The adult female louse lays eggs, called nits, and glues them at the base of the hair shaft. Nits are placed within 1-2 mm of the scalp, where the temperature is optimal for incubation. The female head louse lays as many as 10 eggs per 24 hours, usually at night. […] Nits hatch in about 8-9 days if they are kept near body temperature and mature in another 9-12 days.

• #22 Pediculosis and Pthiriasis (Lice Infestation): Background, Pathophysiology, Etiology

  https://emedicine.medscape.com/article/225013-overview

  Head louse infestation is spread by close physical contact and occasionally by shared fomites (eg, combs, brushes, hats, scarves, bedding). […] The head louse has difficulty attaching firmly to smooth surfaces (eg, glass, metal, plastic, synthetic leathers). […] The 3 types of human lice include the head louse (Pediculus humanus capitis), the body louse (Pediculus humanus corporis), and the crab louse (Pthirus pubis). Body lice infest clothing, laying their eggs on fibers in the fabric seams. Head and pubic lice infest hair, laying their eggs at the base of hair fibers. […] The average nit (ie, ovum) of the 3 types of lice is 0.8 mm long. The nit attaches to the base of the hair shaft (in the case of head or pubic lice) or to fibers of clothing (in the case of body lice) with a strong, highly insoluble cement; thus, nits are difficult to remove. […] The ova require optimum conditions of 30C and 70% humidity to hatch within the average time frame of 8-10 days; the incubation period is longer at lower temperatures.

• #23 Pediculosis and Pthiriasis (Lice Infestation): Background, Pathophysiology, Etiology

  https://emedicine.medscape.com/article/225013-overview

  Head louse infestation is spread by close physical contact and occasionally by shared fomites (eg, combs, brushes, hats, scarves, bedding). […] The head louse has difficulty attaching firmly to smooth surfaces (eg, glass, metal, plastic, synthetic leathers). […] The 3 types of human lice include the head louse (Pediculus humanus capitis), the body louse (Pediculus humanus corporis), and the crab louse (Pthirus pubis). Body lice infest clothing, laying their eggs on fibers in the fabric seams. Head and pubic lice infest hair, laying their eggs at the base of hair fibers. […] The average nit (ie, ovum) of the 3 types of lice is 0.8 mm long. The nit attaches to the base of the hair shaft (in the case of head or pubic lice) or to fibers of clothing (in the case of body lice) with a strong, highly insoluble cement; thus, nits are difficult to remove. […] The ova require optimum conditions of 30C and 70% humidity to hatch within the average time frame of 8-10 days; the incubation period is longer at lower temperatures.

• #24 Pediculosis capitis pathophysiology – wikidoc

  https://www.wikidoc.org/index.php/Pediculosis_capitis_pathophysiology

  Life cycle of Head lice. The life cycle of the head louse has three stages: egg, nymph, and adult. Eggs: Nits are head lice eggs. They are hard to see and are often confused for dandruff or hair spray droplets. Nits are laid by the adult female and are cemented at the base of the hair shaft nearest the scalp. They are 0.8 mm by 0.3 mm, oval and usually yellow to white. Nits take about 1 week to hatch (range 6 to 9 days). Viable eggs are usually located within 6 mm of the scalp. […] Nymphs: The egg hatches to release a nymph. The nit shell then becomes a more visible dull yellow and remains attached to the hair shaft. The nymph looks like an adult head louse, but is about the size of a pinhead. Nymphs mature after three molts and become adults about 7 days after hatching. […] Adults: The adult louse is about the size of a sesame seed, has 6 legs (each with claws), and is tan to grayish-white. In persons with dark hair, the adult louse will appear darker. Females are usually larger than males and can lay up to 8 nits per day. Adult lice can live up to 30 days on a persons head. To live, adult lice need to feed on blood several times daily. Without blood meals, the louse will die within 1 to 2 days off the host.

• #25 Biology and Control of Human Lice | NC State Extension Publications

  https://content.ces.ncsu.edu/biology-and-control-of-human-lice

  Head lice (Pediculus humanus capitatus) live on the scalp and, for all practical purposes, occur only on the head. Adult female lice glue eggs („nits”) to the base of a hair shaft, frequently behind the ears or on the nape of the neck. Nits require high heat and humidity to develop. If conditions are supportive, nits will hatch in about 5-10 days and the light-colored nymphs begin feeding immediately. If the first instar does not feed within 24 hours post-emergence, it will die. Development from egg to adult takes approximately 3 weeks. The adult life stage can survive for 20 or so days in ideal conditions. […] Head lice are not known to transmit any disease organisms. However, their feeding activity irritates the scalp, causing intense itching. Secondary infections can result if the skin is broken by repeatedly scratching affected areas of the scalp. […] Because head lice spend so much time on the body versus the environment, they are considered a medical problem and should be treated as such. Pesticides applied in the environment do nearly nothing to reduce the presence of lice.

• #26 Biology and Control of Human Lice | NC State Extension Publications

  https://content.ces.ncsu.edu/biology-and-control-of-human-lice

  Head lice (Pediculus humanus capitatus) live on the scalp and, for all practical purposes, occur only on the head. Adult female lice glue eggs („nits”) to the base of a hair shaft, frequently behind the ears or on the nape of the neck. Nits require high heat and humidity to develop. If conditions are supportive, nits will hatch in about 5-10 days and the light-colored nymphs begin feeding immediately. If the first instar does not feed within 24 hours post-emergence, it will die. Development from egg to adult takes approximately 3 weeks. The adult life stage can survive for 20 or so days in ideal conditions. […] Head lice are not known to transmit any disease organisms. However, their feeding activity irritates the scalp, causing intense itching. Secondary infections can result if the skin is broken by repeatedly scratching affected areas of the scalp. […] Because head lice spend so much time on the body versus the environment, they are considered a medical problem and should be treated as such. Pesticides applied in the environment do nearly nothing to reduce the presence of lice.

• #27 Pediculosis capitis pathophysiology – wikidoc

  https://www.wikidoc.org/index.php/Pediculosis_capitis_pathophysiology

  Life cycle of Head lice. The life cycle of the head louse has three stages: egg, nymph, and adult. Eggs: Nits are head lice eggs. They are hard to see and are often confused for dandruff or hair spray droplets. Nits are laid by the adult female and are cemented at the base of the hair shaft nearest the scalp. They are 0.8 mm by 0.3 mm, oval and usually yellow to white. Nits take about 1 week to hatch (range 6 to 9 days). Viable eggs are usually located within 6 mm of the scalp. […] Nymphs: The egg hatches to release a nymph. The nit shell then becomes a more visible dull yellow and remains attached to the hair shaft. The nymph looks like an adult head louse, but is about the size of a pinhead. Nymphs mature after three molts and become adults about 7 days after hatching. […] Adults: The adult louse is about the size of a sesame seed, has 6 legs (each with claws), and is tan to grayish-white. In persons with dark hair, the adult louse will appear darker. Females are usually larger than males and can lay up to 8 nits per day. Adult lice can live up to 30 days on a persons head. To live, adult lice need to feed on blood several times daily. Without blood meals, the louse will die within 1 to 2 days off the host.

• #28 Azthena logo with the word Azthena

  https://www.news-medical.net/health/Causes-of-head-lice.aspx

  Head lice infestation is caused by a tiny insect called the Pediculus humanus capitis. […] The lice have mouth parts with 6 hooklets. These attach to the human skin during feeding. […] Lice feed nearly 5 times a day for approximately 35-45 minutes each time. […] The hatching of the egg produces the nymph that moults three times over 7 to 10 days to form the adult.

• #29 Head lice. Pediculosis capitis

  https://dermnetnz.org/topics/head-lice

  Head lice are small, wingless insects that infest the human scalp. They are the most common of the 3 human lice species. […] The head louse, Pediculus humanus capitis, is an ectoparasite that feeds on human blood. It is 23 mm in length and has a flattened, elongated, grey coloured body that becomes reddish after feeding. The louse clings to the hair shaft by its 6 claws and rapidly moves from hair to hair. […] Lice inject anticoagulant saliva into a person’s scalp to suck up the blood up to five times a day. They die within one to two days away from the scalp if they are unable to feed. […] The louse nymph reaches full maturity around 10 days after hatching and the cycle begins again. An adult louse survives on the scalp for about one month, and away from the scalp for up to 48 hours.

• #30 Head lice | UMN Extension

  https://extension.umn.edu/biting-insects/head-lice

  Head lice do not jump or fly. […] Adult females attach eggs to individual hairs close (within 1/4 inch) to the scalp, especially behind the ears and on the nape of the neck. […] Young head lice (called nymphs) feed daily on blood and develop into adults in about 9 to 12 days. […] Adults live for about 30 days. […] There is pesticide resistance: Resistance is when a pesticide no longer kills head lice. […] Resistance can be a problem with products containing permethrins (Nix) or pyrethrins (Rid).

• #31 Pediculosis capitis pathophysiology – wikidoc

  https://www.wikidoc.org/index.php/Pediculosis_capitis_pathophysiology

  Life cycle of Head lice. The life cycle of the head louse has three stages: egg, nymph, and adult. Eggs: Nits are head lice eggs. They are hard to see and are often confused for dandruff or hair spray droplets. Nits are laid by the adult female and are cemented at the base of the hair shaft nearest the scalp. They are 0.8 mm by 0.3 mm, oval and usually yellow to white. Nits take about 1 week to hatch (range 6 to 9 days). Viable eggs are usually located within 6 mm of the scalp. […] Nymphs: The egg hatches to release a nymph. The nit shell then becomes a more visible dull yellow and remains attached to the hair shaft. The nymph looks like an adult head louse, but is about the size of a pinhead. Nymphs mature after three molts and become adults about 7 days after hatching. […] Adults: The adult louse is about the size of a sesame seed, has 6 legs (each with claws), and is tan to grayish-white. In persons with dark hair, the adult louse will appear darker. Females are usually larger than males and can lay up to 8 nits per day. Adult lice can live up to 30 days on a persons head. To live, adult lice need to feed on blood several times daily. Without blood meals, the louse will die within 1 to 2 days off the host.

• #32 Pediculosis capitis pathophysiology – wikidoc

  https://www.wikidoc.org/index.php/Pediculosis_capitis_pathophysiology

  Life cycle of Head lice. The life cycle of the head louse has three stages: egg, nymph, and adult. Eggs: Nits are head lice eggs. They are hard to see and are often confused for dandruff or hair spray droplets. Nits are laid by the adult female and are cemented at the base of the hair shaft nearest the scalp. They are 0.8 mm by 0.3 mm, oval and usually yellow to white. Nits take about 1 week to hatch (range 6 to 9 days). Viable eggs are usually located within 6 mm of the scalp. […] Nymphs: The egg hatches to release a nymph. The nit shell then becomes a more visible dull yellow and remains attached to the hair shaft. The nymph looks like an adult head louse, but is about the size of a pinhead. Nymphs mature after three molts and become adults about 7 days after hatching. […] Adults: The adult louse is about the size of a sesame seed, has 6 legs (each with claws), and is tan to grayish-white. In persons with dark hair, the adult louse will appear darker. Females are usually larger than males and can lay up to 8 nits per day. Adult lice can live up to 30 days on a persons head. To live, adult lice need to feed on blood several times daily. Without blood meals, the louse will die within 1 to 2 days off the host.

• #33 Pediculosis capitis pathophysiology – wikidoc

  https://www.wikidoc.org/index.php/Pediculosis_capitis_pathophysiology

  Life cycle of Head lice. The life cycle of the head louse has three stages: egg, nymph, and adult. Eggs: Nits are head lice eggs. They are hard to see and are often confused for dandruff or hair spray droplets. Nits are laid by the adult female and are cemented at the base of the hair shaft nearest the scalp. They are 0.8 mm by 0.3 mm, oval and usually yellow to white. Nits take about 1 week to hatch (range 6 to 9 days). Viable eggs are usually located within 6 mm of the scalp. […] Nymphs: The egg hatches to release a nymph. The nit shell then becomes a more visible dull yellow and remains attached to the hair shaft. The nymph looks like an adult head louse, but is about the size of a pinhead. Nymphs mature after three molts and become adults about 7 days after hatching. […] Adults: The adult louse is about the size of a sesame seed, has 6 legs (each with claws), and is tan to grayish-white. In persons with dark hair, the adult louse will appear darker. Females are usually larger than males and can lay up to 8 nits per day. Adult lice can live up to 30 days on a persons head. To live, adult lice need to feed on blood several times daily. Without blood meals, the louse will die within 1 to 2 days off the host.

• #34 Pediculosis capitis pathophysiology – wikidoc

  https://www.wikidoc.org/index.php/Pediculosis_capitis_pathophysiology

  Life cycle of Head lice. The life cycle of the head louse has three stages: egg, nymph, and adult. Eggs: Nits are head lice eggs. They are hard to see and are often confused for dandruff or hair spray droplets. Nits are laid by the adult female and are cemented at the base of the hair shaft nearest the scalp. They are 0.8 mm by 0.3 mm, oval and usually yellow to white. Nits take about 1 week to hatch (range 6 to 9 days). Viable eggs are usually located within 6 mm of the scalp. […] Nymphs: The egg hatches to release a nymph. The nit shell then becomes a more visible dull yellow and remains attached to the hair shaft. The nymph looks like an adult head louse, but is about the size of a pinhead. Nymphs mature after three molts and become adults about 7 days after hatching. […] Adults: The adult louse is about the size of a sesame seed, has 6 legs (each with claws), and is tan to grayish-white. In persons with dark hair, the adult louse will appear darker. Females are usually larger than males and can lay up to 8 nits per day. Adult lice can live up to 30 days on a persons head. To live, adult lice need to feed on blood several times daily. Without blood meals, the louse will die within 1 to 2 days off the host.

• #35 Head lice. Pediculosis capitis

  https://dermnetnz.org/topics/head-lice

  Head lice are small, wingless insects that infest the human scalp. They are the most common of the 3 human lice species. […] The head louse, Pediculus humanus capitis, is an ectoparasite that feeds on human blood. It is 23 mm in length and has a flattened, elongated, grey coloured body that becomes reddish after feeding. The louse clings to the hair shaft by its 6 claws and rapidly moves from hair to hair. […] Lice inject anticoagulant saliva into a person’s scalp to suck up the blood up to five times a day. They die within one to two days away from the scalp if they are unable to feed. […] The louse nymph reaches full maturity around 10 days after hatching and the cycle begins again. An adult louse survives on the scalp for about one month, and away from the scalp for up to 48 hours.

• #36 Head louse – Wikipedia

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

  The head louse (Pediculus humanus capitis) is an obligate ectoparasite of humans. Head lice are wingless insects that spend their entire lives on the human scalp and feed exclusively on human blood. […] Lice differ from other hematophagic ectoparasites such as fleas in spending their entire lifecycle on a host. […] Like other members of the Anoplura, head louse mouthparts are highly adapted for piercing the skin and sucking blood. […] All stages except eggs are blood-feeders and bite the skin four to five times daily to feed. They inject saliva which contains an anticoagulant and suck blood. […] Head lice reproduce sexually, and copulation is necessary for the female to produce fertile eggs. Parthenogenesis, the production of viable offspring by virgin females, does not occur in Pediculus humanus. […] During its lifespan of 4 weeks a female louse lays 50-150 eggs. Eggs hatch within 6-9 days, each nymphal stage lasts for 4-5 days and accordingly the period from egg to adults lasts for 18-24 days.

• #37 Head louse – Wikipedia

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

  The head louse (Pediculus humanus capitis) is an obligate ectoparasite of humans. Head lice are wingless insects that spend their entire lives on the human scalp and feed exclusively on human blood. […] Lice differ from other hematophagic ectoparasites such as fleas in spending their entire lifecycle on a host. […] Like other members of the Anoplura, head louse mouthparts are highly adapted for piercing the skin and sucking blood. […] All stages except eggs are blood-feeders and bite the skin four to five times daily to feed. They inject saliva which contains an anticoagulant and suck blood. […] Head lice reproduce sexually, and copulation is necessary for the female to produce fertile eggs. Parthenogenesis, the production of viable offspring by virgin females, does not occur in Pediculus humanus. […] During its lifespan of 4 weeks a female louse lays 50-150 eggs. Eggs hatch within 6-9 days, each nymphal stage lasts for 4-5 days and accordingly the period from egg to adults lasts for 18-24 days.

• #38 Pediculosis – StatPearls – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK470343/

  Patients frequently present with pruritis, typically from an immune-mediated hypersensitivity reaction. It may take 2 to 6 weeks to develop symptoms after the first exposure, while pruritis can develop 1 or 2 days after re-exposure. […] The head louse is an obligate parasite that spends its entire life on the human host. Head lice feed exclusively on blood. Lice are unable to jump or fly, and transmission requires close contact. Transmission of head lice is thought to occur by head-to-head contact, sharing of headgear, or other direct contact with fomites (inanimate objects that harbor the organism, such as movie seats). […] Pharmacologic treatment of lice focuses on 2 mechanisms: neurotoxicity resulting in paralysis of the louse and suffocation from topical application. […] Permethrin affects sodium transport across neuronal membranes, causing respiratory paralysis in arthropods.

• #39 Head lice – Symptoms & causes – Mayo Clinic

  https://www.mayoclinic.org/diseases-conditions/head-lice/symptoms-causes/syc-20356180

  Head lice are tiny insects that feed on blood from the human scalp. Head lice most often affect children. The insects usually spread through direct transfer from the hair of one person to the hair of another. […] Head lice feed on blood from the scalp. The female louse lays eggs (nits) that stick to hair shafts. […] A head louse is a tan or grayish insect about the size of a strawberry seed. It feeds on human blood from the scalp. The female louse produces a sticky substance that firmly attaches each egg to the base of a hair shaft less than 1/4 inch (5 millimeters) from the scalp. […] Head lice crawl, but they can’t jump or fly. Head lice often spread from one person to another by direct head-to-head contact, often within a family or among children who have close contact at school or play.

• #40 Head lice – Symptoms & causes – Mayo Clinic

  https://www.mayoclinic.org/diseases-conditions/head-lice/symptoms-causes/syc-20356180

  Head lice are tiny insects that feed on blood from the human scalp. Head lice most often affect children. The insects usually spread through direct transfer from the hair of one person to the hair of another. […] Head lice feed on blood from the scalp. The female louse lays eggs (nits) that stick to hair shafts. […] A head louse is a tan or grayish insect about the size of a strawberry seed. It feeds on human blood from the scalp. The female louse produces a sticky substance that firmly attaches each egg to the base of a hair shaft less than 1/4 inch (5 millimeters) from the scalp. […] Head lice crawl, but they can’t jump or fly. Head lice often spread from one person to another by direct head-to-head contact, often within a family or among children who have close contact at school or play.

• #41 Frontiers | Where Are We With Human Lice? A Review of the Current State of Knowledge

  https://www.frontiersin.org/journals/cellular-and-infection-microbiology/articles/10.3389/fcimb.2019.00474/full

  Pediculus humanus is an obligate bloodsucking ectoparasite of human that includes two ecotypes, head louse and body louse, which differ slightly in morphology and biology, but have distinct ecologies. […] Recent studies suggested that not only body louse, but also head louse can transmit disease, which warrants greater attention as a serious public health problem. […] The recent sequencing of body louse genome confirmed that P. humanus has the smallest genome of any hemimetabolous insect reported to date, and also revealed numerous interesting characteristics in the nuclear and mitochondrial genomes. […] Current lice control strategies have proven unsuccessful. […] Therefore, novel opportunities for pest control strategies are needed. […] Head louse infestation is very common worldwide, especially among schoolchildren, whatever their hygiene status, and the transmission occurs mainly by head-to-head contact.

• #42 Pediculosis and Pthiriasis (Lice Infestation): Background, Pathophysiology, Etiology

  https://emedicine.medscape.com/article/225013-overview

  Head louse infestation is spread by close physical contact and occasionally by shared fomites (eg, combs, brushes, hats, scarves, bedding). […] The head louse has difficulty attaching firmly to smooth surfaces (eg, glass, metal, plastic, synthetic leathers). […] The 3 types of human lice include the head louse (Pediculus humanus capitis), the body louse (Pediculus humanus corporis), and the crab louse (Pthirus pubis). Body lice infest clothing, laying their eggs on fibers in the fabric seams. Head and pubic lice infest hair, laying their eggs at the base of hair fibers. […] The average nit (ie, ovum) of the 3 types of lice is 0.8 mm long. The nit attaches to the base of the hair shaft (in the case of head or pubic lice) or to fibers of clothing (in the case of body lice) with a strong, highly insoluble cement; thus, nits are difficult to remove. […] The ova require optimum conditions of 30C and 70% humidity to hatch within the average time frame of 8-10 days; the incubation period is longer at lower temperatures.

• #43 Head lice | UMN Extension

  https://extension.umn.edu/biting-insects/head-lice

  Head lice do not jump or fly. […] Adult females attach eggs to individual hairs close (within 1/4 inch) to the scalp, especially behind the ears and on the nape of the neck. […] Young head lice (called nymphs) feed daily on blood and develop into adults in about 9 to 12 days. […] Adults live for about 30 days. […] There is pesticide resistance: Resistance is when a pesticide no longer kills head lice. […] Resistance can be a problem with products containing permethrins (Nix) or pyrethrins (Rid).

• #44 Pediculosis and Pthiriasis (Lice Infestation): Background, Pathophysiology, Etiology

  https://emedicine.medscape.com/article/225013-overview

  Head louse infestation is spread by close physical contact and occasionally by shared fomites (eg, combs, brushes, hats, scarves, bedding). […] The head louse has difficulty attaching firmly to smooth surfaces (eg, glass, metal, plastic, synthetic leathers). […] The 3 types of human lice include the head louse (Pediculus humanus capitis), the body louse (Pediculus humanus corporis), and the crab louse (Pthirus pubis). Body lice infest clothing, laying their eggs on fibers in the fabric seams. Head and pubic lice infest hair, laying their eggs at the base of hair fibers. […] The average nit (ie, ovum) of the 3 types of lice is 0.8 mm long. The nit attaches to the base of the hair shaft (in the case of head or pubic lice) or to fibers of clothing (in the case of body lice) with a strong, highly insoluble cement; thus, nits are difficult to remove. […] The ova require optimum conditions of 30C and 70% humidity to hatch within the average time frame of 8-10 days; the incubation period is longer at lower temperatures.

• #45 Frontiers | Where Are We With Human Lice? A Review of the Current State of Knowledge

  https://www.frontiersin.org/journals/cellular-and-infection-microbiology/articles/10.3389/fcimb.2019.00474/full

  Pediculus humanus is an obligate bloodsucking ectoparasite of human that includes two ecotypes, head louse and body louse, which differ slightly in morphology and biology, but have distinct ecologies. […] Recent studies suggested that not only body louse, but also head louse can transmit disease, which warrants greater attention as a serious public health problem. […] The recent sequencing of body louse genome confirmed that P. humanus has the smallest genome of any hemimetabolous insect reported to date, and also revealed numerous interesting characteristics in the nuclear and mitochondrial genomes. […] Current lice control strategies have proven unsuccessful. […] Therefore, novel opportunities for pest control strategies are needed. […] Head louse infestation is very common worldwide, especially among schoolchildren, whatever their hygiene status, and the transmission occurs mainly by head-to-head contact.

• #46 Head lice – Symptoms & causes – Mayo Clinic

  https://www.mayoclinic.org/diseases-conditions/head-lice/symptoms-causes/syc-20356180

  Head lice are spread primarily by direct head-to-head contact. So the risk of spreading head lice is greatest among children who play or go to school together. In the United States, cases of head lice most often occur in children in preschool through elementary school. […] If your child scratches an itchy scalp due to head lice, it’s possible for the skin to break and develop an infection.

• #47 Head Lice: Causes and Risk Factors

  https://www.verywellhealth.com/head-lice-causes-and-risk-factors-2633641

  The head louse is the parasitic insect Pediculus humanus capitis. Head lice like to live close to the scalp where they feed several times a day on blood. They can be found on the hair of the head, eyebrows, and eyelashes. They are especially likely to be found behind the ears and at the neckline. […] While lice are a nuisance, they do not spread disease. […] Adult lice can live for up to 30 days on the head. They will quickly die if they leave the scalp, perhaps surviving up to a day or two at most, as they need to feed frequently. […] Lice infestations are not related to hygiene, either personal (showering, washing hair) or environmental (the cleanliness of the home or school). […] Lice are minuscule parasitic insects. They’re unrelated to any sort of microbial infection and do not spread disease. However, in very rare cases, scratching caused by extreme itching can lead to a secondary bacterial infection if the skin is broken.

• #48 Head lice as vectors of pathogenic microorganisms

  https://pmc.ncbi.nlm.nih.gov/articles/PMC10510260/

  Body lice and head lice are the most common ectoparasites of humans. […] The vector capacity of head lice is still a matter of debate. […] Data from epidemiological studies as well as historical observations demonstrate that body lice and head lice can carry the same array of pathogens. […] Since the presence of a bacterial pathogen in an arthropod is not sufficient to state that it can be transmitted to humans, and since experimental models are lacking, as yet one cannot conclude with certainty that head lice serve as vectors, although this review presents circumstantial evidence that they do. […] Adequately designed experimental and epidemiological studies are needed to ascertain the exact transmission potential of head lice. […] If head lice have a similar vector capacity for the transmission of important bacterial pathogens, then the potential health threat caused by head lice infestation should be several orders of magnitude greater compared to body lice.

• #49 Frontiers | Where Are We With Human Lice? A Review of the Current State of Knowledge

  https://www.frontiersin.org/journals/cellular-and-infection-microbiology/articles/10.3389/fcimb.2019.00474/full

  Body louse is the major vector of three humans pathogenic bacteria, which are: Rickettsia prowazekii, Borrelia recurrentis, and Bartonella quintana. […] The transmission of these infections to uninfected people occurs through the feces or crushed bodies of infected lice, that contaminate the bite sites, conjunctiva, mucous membranes or microlesions of the skin. […] In recent decades, there has been a growing recognition that head lice are vectors of pathogens, which has changed the long-established paradigm that only body lice are vectors of disease. […] The potential of head lice as disease vector is not yet fully understood. […] Based on the combined evidence of both epidemiological and laboratory studies, we believe that head lice can transmit disease to their human host under favorable epidemiological conditions, although its vectorial capacity is weaker compared to body lice.

• #50 Head lice as vectors of pathogenic microorganisms

  https://pmc.ncbi.nlm.nih.gov/articles/PMC10510260/

  Historical observations indicate that body lice and head lice could have transferred Y. pestis, B. quintana, and R. prowazekii from sick to healthy individuals. […] It should be noted that transmission of B. quintana is particular in the sense that faecal material of lice containing the pathogen has to be actively introduced into the skin, usually by scratching. […] Data from epidemiological studies indicate that head lice carry the same panel of bacterial pathogens as body lice, namely, R. prowazekii, B. quintana, B. recurrentis, Y. pestis, C. burneti and even Acinetobacter spp. […] Whether body lice and head lice actually have the same potential to transmit bacterial pathogens cannot be ascertained from the existing data.

• #51 Head lice as vectors of pathogenic microorganisms | Tropical Medicine and Health | Full Text

  https://tropmedhealth.biomedcentral.com/articles/10.1186/s41182-023-00545-5

  In contrast, rather few experimental studies were performed with head lice. […] Hitherto, only for R. prowazekii it was demonstrated that head lice can actively transmit this pathogen. […] Data from epidemiological studies indicate that head lice carry the same panel of bacterial pathogens as body lice, namely, R. prowazekii, B. quintana, B. recurrentis, Y. pestis, C. burneti and even Acinetobacter spp. […] It goes without saying that the presence of a bacterial pathogen in an arthropod is not sufficient to conclude that it can transmit to humans. […] Whether body lice and head lice actually have the same potential to transmit bacterial pathogens cannot be ascertained from the existing data. Further research is needed using standardized experimental models.

• #52 Head lice as vectors of pathogenic microorganisms

  https://pmc.ncbi.nlm.nih.gov/articles/PMC10510260/

  Historical observations indicate that body lice and head lice could have transferred Y. pestis, B. quintana, and R. prowazekii from sick to healthy individuals. […] It should be noted that transmission of B. quintana is particular in the sense that faecal material of lice containing the pathogen has to be actively introduced into the skin, usually by scratching. […] Data from epidemiological studies indicate that head lice carry the same panel of bacterial pathogens as body lice, namely, R. prowazekii, B. quintana, B. recurrentis, Y. pestis, C. burneti and even Acinetobacter spp. […] Whether body lice and head lice actually have the same potential to transmit bacterial pathogens cannot be ascertained from the existing data.

• #53 Head lice as vectors of pathogenic microorganisms

  https://pmc.ncbi.nlm.nih.gov/articles/PMC10510260/

  Historical observations indicate that body lice and head lice could have transferred Y. pestis, B. quintana, and R. prowazekii from sick to healthy individuals. […] It should be noted that transmission of B. quintana is particular in the sense that faecal material of lice containing the pathogen has to be actively introduced into the skin, usually by scratching. […] Data from epidemiological studies indicate that head lice carry the same panel of bacterial pathogens as body lice, namely, R. prowazekii, B. quintana, B. recurrentis, Y. pestis, C. burneti and even Acinetobacter spp. […] Whether body lice and head lice actually have the same potential to transmit bacterial pathogens cannot be ascertained from the existing data.

• #54 Head lice as vectors of pathogenic microorganisms

  https://pmc.ncbi.nlm.nih.gov/articles/PMC10510260/

  Body lice and head lice are the most common ectoparasites of humans. […] The vector capacity of head lice is still a matter of debate. […] Data from epidemiological studies as well as historical observations demonstrate that body lice and head lice can carry the same array of pathogens. […] Since the presence of a bacterial pathogen in an arthropod is not sufficient to state that it can be transmitted to humans, and since experimental models are lacking, as yet one cannot conclude with certainty that head lice serve as vectors, although this review presents circumstantial evidence that they do. […] Adequately designed experimental and epidemiological studies are needed to ascertain the exact transmission potential of head lice. […] If head lice have a similar vector capacity for the transmission of important bacterial pathogens, then the potential health threat caused by head lice infestation should be several orders of magnitude greater compared to body lice.

• #55 Head lice as vectors of pathogenic microorganisms | Tropical Medicine and Health | Full Text

  https://tropmedhealth.biomedcentral.com/articles/10.1186/s41182-023-00545-5

  In contrast, rather few experimental studies were performed with head lice. […] Hitherto, only for R. prowazekii it was demonstrated that head lice can actively transmit this pathogen. […] Data from epidemiological studies indicate that head lice carry the same panel of bacterial pathogens as body lice, namely, R. prowazekii, B. quintana, B. recurrentis, Y. pestis, C. burneti and even Acinetobacter spp. […] It goes without saying that the presence of a bacterial pathogen in an arthropod is not sufficient to conclude that it can transmit to humans. […] Whether body lice and head lice actually have the same potential to transmit bacterial pathogens cannot be ascertained from the existing data. Further research is needed using standardized experimental models.

• #56 Head lice as vectors of pathogenic microorganisms | Tropical Medicine and Health | Full Text

  https://tropmedhealth.biomedcentral.com/articles/10.1186/s41182-023-00545-5

  In contrast, rather few experimental studies were performed with head lice. […] Hitherto, only for R. prowazekii it was demonstrated that head lice can actively transmit this pathogen. […] Data from epidemiological studies indicate that head lice carry the same panel of bacterial pathogens as body lice, namely, R. prowazekii, B. quintana, B. recurrentis, Y. pestis, C. burneti and even Acinetobacter spp. […] It goes without saying that the presence of a bacterial pathogen in an arthropod is not sufficient to conclude that it can transmit to humans. […] Whether body lice and head lice actually have the same potential to transmit bacterial pathogens cannot be ascertained from the existing data. Further research is needed using standardized experimental models.

• #57 Head lice as vectors of pathogenic microorganisms

  https://pmc.ncbi.nlm.nih.gov/articles/PMC10510260/

  Body lice and head lice are the most common ectoparasites of humans. […] The vector capacity of head lice is still a matter of debate. […] Data from epidemiological studies as well as historical observations demonstrate that body lice and head lice can carry the same array of pathogens. […] Since the presence of a bacterial pathogen in an arthropod is not sufficient to state that it can be transmitted to humans, and since experimental models are lacking, as yet one cannot conclude with certainty that head lice serve as vectors, although this review presents circumstantial evidence that they do. […] Adequately designed experimental and epidemiological studies are needed to ascertain the exact transmission potential of head lice. […] If head lice have a similar vector capacity for the transmission of important bacterial pathogens, then the potential health threat caused by head lice infestation should be several orders of magnitude greater compared to body lice.

• #58 Head lice as vectors of pathogenic microorganisms

  https://pmc.ncbi.nlm.nih.gov/articles/PMC10510260/

  Body lice and head lice are the most common ectoparasites of humans. […] The vector capacity of head lice is still a matter of debate. […] Data from epidemiological studies as well as historical observations demonstrate that body lice and head lice can carry the same array of pathogens. […] Since the presence of a bacterial pathogen in an arthropod is not sufficient to state that it can be transmitted to humans, and since experimental models are lacking, as yet one cannot conclude with certainty that head lice serve as vectors, although this review presents circumstantial evidence that they do. […] Adequately designed experimental and epidemiological studies are needed to ascertain the exact transmission potential of head lice. […] If head lice have a similar vector capacity for the transmission of important bacterial pathogens, then the potential health threat caused by head lice infestation should be several orders of magnitude greater compared to body lice.

• #59 Head lice as vectors of pathogenic microorganisms | Tropical Medicine and Health | Full Text

  https://tropmedhealth.biomedcentral.com/articles/10.1186/s41182-023-00545-5

  Body lice and head lice are the most common ectoparasites of humans. […] The vector capacity of head lice is still a matter of debate. […] Data from epidemiological studies as well as historical observations demonstrate that body lice and head lice can carry the same array of pathogens. […] Since the presence of a bacterial pathogen in an arthropod is not sufficient to state that it can be transmitted to humans, and since experimental models are lacking, as yet one cannot conclude with certainty that head lice serve as vectors, although this review presents circumstantial evidence that they do. […] Adequately designed experimental and epidemiological studies are needed to ascertain the exact transmission potential of head lice. […] If head lice have a similar vector capacity for the transmission of important bacterial pathogens, then the potential health threat caused by head lice infestation should be several orders of magnitude greater compared to body lice.

• #60 Pediculosis – StatPearls – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK470343/

  Patients frequently present with pruritis, typically from an immune-mediated hypersensitivity reaction. It may take 2 to 6 weeks to develop symptoms after the first exposure, while pruritis can develop 1 or 2 days after re-exposure. […] The head louse is an obligate parasite that spends its entire life on the human host. Head lice feed exclusively on blood. Lice are unable to jump or fly, and transmission requires close contact. Transmission of head lice is thought to occur by head-to-head contact, sharing of headgear, or other direct contact with fomites (inanimate objects that harbor the organism, such as movie seats). […] Pharmacologic treatment of lice focuses on 2 mechanisms: neurotoxicity resulting in paralysis of the louse and suffocation from topical application. […] Permethrin affects sodium transport across neuronal membranes, causing respiratory paralysis in arthropods.

• #61 Pediculosis – StatPearls – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK470343/

  Patients frequently present with pruritis, typically from an immune-mediated hypersensitivity reaction. It may take 2 to 6 weeks to develop symptoms after the first exposure, while pruritis can develop 1 or 2 days after re-exposure. […] The head louse is an obligate parasite that spends its entire life on the human host. Head lice feed exclusively on blood. Lice are unable to jump or fly, and transmission requires close contact. Transmission of head lice is thought to occur by head-to-head contact, sharing of headgear, or other direct contact with fomites (inanimate objects that harbor the organism, such as movie seats). […] Pharmacologic treatment of lice focuses on 2 mechanisms: neurotoxicity resulting in paralysis of the louse and suffocation from topical application. […] Permethrin affects sodium transport across neuronal membranes, causing respiratory paralysis in arthropods.

• #62 The Prevention and Treatment of Head Lice in Children

  https://www.uspharmacist.com/article/the-prevention-and-treatment-of-head-lice-in-children-32935

  Louse saliva, which contains vasodilators and anticoagulants, is injected into the host while the louse is feeding on the hosts blood. The host usually develops a sensitivity to the saliva, resulting in pruritus; however, it may take 4 to 6 weeks for the sensitivity and itching to manifest. […] The optimal treatment would be readily available, easy to use, effective and safe, affordable, and nonresistance-promoting. […] Permethrin causes hyperstimulation of the nervous system of lice, resulting in paralysis and death. […] Malathion is an organophosphate that inhibits cholinesterase activity, resulting in increased acetylcholine concentrations. The excess cholinergic activity causes hyperstimulation of the louse nervous system and prevents feeding. […] Spinosad is indicated for use in patients aged 4 years and older. The mechanism of action (MOA) is hyperexcitability of the louse nervous system that results in paralysis and death.

• #63 Pediculosis – StatPearls – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK470343/

  Malathion 0.5% is an organophosphate cholinesterase inhibitor that causes respiratory paralysis in arthropods. […] Lindane 1% is an organochloride that kills lice by respiratory paralysis. […] Benzyl alcohol 5% lotion was approved in 2009 as a topical suffocation treatment that prevents lice from closing their respiratory spiracles. […] Spinosad 0.9% is a topical pediculicidal agent that was approved in 2011. It works by provoking hyperexcitation, causing death by paralysis. […] Topical ivermectin 0.5% lotion increases chloride in muscle cells, causing hyperpolarization and paralysis. […] The only currently used oral treatment for pediculosis is ivermectin. Ivermectin also has a risk of neurotoxicity. […] Body lice are eradicated through proper hygiene, laundering, or insecticide application to affected clothing. […] Frequent lice treatment is also known to cause severe itching, which can lead to skin breakdown and secondary bacterial infections.

• #64 The Prevention and Treatment of Head Lice in Children

  https://www.uspharmacist.com/article/the-prevention-and-treatment-of-head-lice-in-children-32935

  Louse saliva, which contains vasodilators and anticoagulants, is injected into the host while the louse is feeding on the hosts blood. The host usually develops a sensitivity to the saliva, resulting in pruritus; however, it may take 4 to 6 weeks for the sensitivity and itching to manifest. […] The optimal treatment would be readily available, easy to use, effective and safe, affordable, and nonresistance-promoting. […] Permethrin causes hyperstimulation of the nervous system of lice, resulting in paralysis and death. […] Malathion is an organophosphate that inhibits cholinesterase activity, resulting in increased acetylcholine concentrations. The excess cholinergic activity causes hyperstimulation of the louse nervous system and prevents feeding. […] Spinosad is indicated for use in patients aged 4 years and older. The mechanism of action (MOA) is hyperexcitability of the louse nervous system that results in paralysis and death.

• #65 Pediculosis – StatPearls – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK470343/

  Malathion 0.5% is an organophosphate cholinesterase inhibitor that causes respiratory paralysis in arthropods. […] Lindane 1% is an organochloride that kills lice by respiratory paralysis. […] Benzyl alcohol 5% lotion was approved in 2009 as a topical suffocation treatment that prevents lice from closing their respiratory spiracles. […] Spinosad 0.9% is a topical pediculicidal agent that was approved in 2011. It works by provoking hyperexcitation, causing death by paralysis. […] Topical ivermectin 0.5% lotion increases chloride in muscle cells, causing hyperpolarization and paralysis. […] The only currently used oral treatment for pediculosis is ivermectin. Ivermectin also has a risk of neurotoxicity. […] Body lice are eradicated through proper hygiene, laundering, or insecticide application to affected clothing. […] Frequent lice treatment is also known to cause severe itching, which can lead to skin breakdown and secondary bacterial infections.

• #66 Pediculosis – StatPearls – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK470343/

  Malathion 0.5% is an organophosphate cholinesterase inhibitor that causes respiratory paralysis in arthropods. […] Lindane 1% is an organochloride that kills lice by respiratory paralysis. […] Benzyl alcohol 5% lotion was approved in 2009 as a topical suffocation treatment that prevents lice from closing their respiratory spiracles. […] Spinosad 0.9% is a topical pediculicidal agent that was approved in 2011. It works by provoking hyperexcitation, causing death by paralysis. […] Topical ivermectin 0.5% lotion increases chloride in muscle cells, causing hyperpolarization and paralysis. […] The only currently used oral treatment for pediculosis is ivermectin. Ivermectin also has a risk of neurotoxicity. […] Body lice are eradicated through proper hygiene, laundering, or insecticide application to affected clothing. […] Frequent lice treatment is also known to cause severe itching, which can lead to skin breakdown and secondary bacterial infections.

• #67 The Prevention and Treatment of Head Lice in Children

  https://www.uspharmacist.com/article/the-prevention-and-treatment-of-head-lice-in-children-32935

  Louse saliva, which contains vasodilators and anticoagulants, is injected into the host while the louse is feeding on the hosts blood. The host usually develops a sensitivity to the saliva, resulting in pruritus; however, it may take 4 to 6 weeks for the sensitivity and itching to manifest. […] The optimal treatment would be readily available, easy to use, effective and safe, affordable, and nonresistance-promoting. […] Permethrin causes hyperstimulation of the nervous system of lice, resulting in paralysis and death. […] Malathion is an organophosphate that inhibits cholinesterase activity, resulting in increased acetylcholine concentrations. The excess cholinergic activity causes hyperstimulation of the louse nervous system and prevents feeding. […] Spinosad is indicated for use in patients aged 4 years and older. The mechanism of action (MOA) is hyperexcitability of the louse nervous system that results in paralysis and death.

• #68 Pediculosis – StatPearls – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK470343/

  Malathion 0.5% is an organophosphate cholinesterase inhibitor that causes respiratory paralysis in arthropods. […] Lindane 1% is an organochloride that kills lice by respiratory paralysis. […] Benzyl alcohol 5% lotion was approved in 2009 as a topical suffocation treatment that prevents lice from closing their respiratory spiracles. […] Spinosad 0.9% is a topical pediculicidal agent that was approved in 2011. It works by provoking hyperexcitation, causing death by paralysis. […] Topical ivermectin 0.5% lotion increases chloride in muscle cells, causing hyperpolarization and paralysis. […] The only currently used oral treatment for pediculosis is ivermectin. Ivermectin also has a risk of neurotoxicity. […] Body lice are eradicated through proper hygiene, laundering, or insecticide application to affected clothing. […] Frequent lice treatment is also known to cause severe itching, which can lead to skin breakdown and secondary bacterial infections.

• #69 Pediculosis capitis: An update – Indian Journal of Dermatology, Venereology and Leprology

  https://ijdvl.com/pediculosis-capitis-an-update/

  The cuticle of louse is lipoidal and allows penetration of insecticides according to law of partition. As per partition law, insecticides move from higher concentration (drug formulation) to lower concentration (cuticle waxes). The principle of treating ectoparasite infestation is that the parasite should acquire the maximum amount of drug with minimal systemic penetration into human. […] The adult louse is about the size of a sesame seed i.e. 2 – 4 mm, has 6 legs (each with claws), and is tan to grayish-white. […] Ivermectin binds to glutamate-gated chloride channels with high affinity and specificity, which occur in invertebrate nerve and muscle cells, causing an increase in the permeability of the cell membrane to chloride ions of the nerve or muscle cell. This results in hyperpolarization, leading to flaccid paralysis culminating in the death of the parasite.

• #70 Pediculosis – StatPearls – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK470343/

  Malathion 0.5% is an organophosphate cholinesterase inhibitor that causes respiratory paralysis in arthropods. […] Lindane 1% is an organochloride that kills lice by respiratory paralysis. […] Benzyl alcohol 5% lotion was approved in 2009 as a topical suffocation treatment that prevents lice from closing their respiratory spiracles. […] Spinosad 0.9% is a topical pediculicidal agent that was approved in 2011. It works by provoking hyperexcitation, causing death by paralysis. […] Topical ivermectin 0.5% lotion increases chloride in muscle cells, causing hyperpolarization and paralysis. […] The only currently used oral treatment for pediculosis is ivermectin. Ivermectin also has a risk of neurotoxicity. […] Body lice are eradicated through proper hygiene, laundering, or insecticide application to affected clothing. […] Frequent lice treatment is also known to cause severe itching, which can lead to skin breakdown and secondary bacterial infections.

• #71

  https://bpac.org.nz/2017/dimethicone.aspx

  Lice are unlikely to develop resistance to dimethicone lotion as it is not an insecticide and instead kills lice by suffocation. […] Dimethicone is not an insecticide. It kills lice by suffocation and disrupting their ability to regulate water. Products with this mechanism of action may become the preferred treatment for head lice as it is unlikely lice will develop resistance, which can occur with insecticide-based treatments. […] Dimethicone is derived from silicone oil. It is not an insecticide, but eradicates adult and nymph lice via disruption of water homeostasis and suffocation. Due to the mechanism of action of dimethicone, it is thought to be highly unlikely that lice will develop resistance. This may make it a preferable treatment option to insecticide-based treatments, to which lice can develop resistance.

• #72

  https://bpac.org.nz/2017/dimethicone.aspx

  Lice are unlikely to develop resistance to dimethicone lotion as it is not an insecticide and instead kills lice by suffocation. […] Dimethicone is not an insecticide. It kills lice by suffocation and disrupting their ability to regulate water. Products with this mechanism of action may become the preferred treatment for head lice as it is unlikely lice will develop resistance, which can occur with insecticide-based treatments. […] Dimethicone is derived from silicone oil. It is not an insecticide, but eradicates adult and nymph lice via disruption of water homeostasis and suffocation. Due to the mechanism of action of dimethicone, it is thought to be highly unlikely that lice will develop resistance. This may make it a preferable treatment option to insecticide-based treatments, to which lice can develop resistance.

• #73 Pediculosis capitis: An update – Indian Journal of Dermatology, Venereology and Leprology

  https://ijdvl.com/pediculosis-capitis-an-update/

  Resistance to topical pediculicides is an emerging concern in most parts of the world. The problem of resistance to a particular agent is directly related to the frequency of use of that agent in the affected population. A novel mechanism has been elucidated for gaining of resistance in voltage-sensitive sodium channel -subunit gene termed as Knock down resistance (KDR), by virtue of which there is slower killing of lice, which can be encountered by sequential use of pediculicides and systemic agents.

• #74 Head lice. Pediculosis capitis

  https://dermnetnz.org/topics/head-lice

  The main suffocating agent used to kill the adult and nymph head lice is 4% dimethicone (also spelt dimeticone). Lice are unlikely to develop resistance due to the mechanism of action, and the product is safe and well tolerated. […] The most commonly used topical insecticides for head lice is malathion, but resistance has been reported and cure rates are reported to be as low as 33%. Resistance to permethrin, phenothrin and other pyrethrins has increased to the degree that they are no longer recommended in the UK. […] Failure to eradicate lice is a common and frustrating problem. It can be due to: […] The resistance of lice to insecticides.

• #75 Pediculosis capitis: An update – Indian Journal of Dermatology, Venereology and Leprology

  https://ijdvl.com/pediculosis-capitis-an-update/

  Resistance to topical pediculicides is an emerging concern in most parts of the world. The problem of resistance to a particular agent is directly related to the frequency of use of that agent in the affected population. A novel mechanism has been elucidated for gaining of resistance in voltage-sensitive sodium channel -subunit gene termed as Knock down resistance (KDR), by virtue of which there is slower killing of lice, which can be encountered by sequential use of pediculicides and systemic agents.

• #76

  https://bpac.org.nz/2017/dimethicone.aspx

  Lice are unlikely to develop resistance to dimethicone lotion as it is not an insecticide and instead kills lice by suffocation. […] Dimethicone is not an insecticide. It kills lice by suffocation and disrupting their ability to regulate water. Products with this mechanism of action may become the preferred treatment for head lice as it is unlikely lice will develop resistance, which can occur with insecticide-based treatments. […] Dimethicone is derived from silicone oil. It is not an insecticide, but eradicates adult and nymph lice via disruption of water homeostasis and suffocation. Due to the mechanism of action of dimethicone, it is thought to be highly unlikely that lice will develop resistance. This may make it a preferable treatment option to insecticide-based treatments, to which lice can develop resistance.

• #77

  https://bpac.org.nz/2017/dimethicone.aspx

  Adverse effects from using a dimethicone lice treatment are unlikely; in clinical trials of 4% dimethicone lotion, itching or irritation of the scalp or neck was reported by less than 2% of participants. […] Clinical trials of 4% dimethicone lotion report cure rates of 69-92% after two applications one week apart, compared to cure rates of 75% for phenothrin and 33% for malathion. […] It is likely that 4% dimethicone lotion has some ability to kill eggs before they hatch. However, two applications are recommended, one week apart, in order to treat any nymphs (young lice) which hatch from surviving eggs. This interval means that the second application can kill any newly hatched nymphs before they reach the adult stage of development and are able to reproduce.

• #78 Head lice infestations: A clinical update | Canadian Paediatric Society

  https://cps.ca/documents/position/head-lice

  Head lice (Pediculus humanus capitis) infestations are not a primary health hazard or a vector for disease, but they are a societal problem with substantial costs. […] Head lice are wingless, 2 mm to 4 mm long (as adults), six-legged, bloodsucking insects that live on the human scalp. […] The head louse feeds every 3 to 6 hours by sucking blood, injecting saliva simultaneously. […] Itching occurs if the individual with lice becomes sensitized to antigenic components in the saliva injected as the louse feeds. […] An infestation with lice is called pediculosis and usually involves less than 10 live lice. […] The role of fomites in transmission is controversial. […] Definitive diagnosis of head lice infestation requires the detection of a living louse. […] Because head lice move quickly, their detection requires a degree of expertise and experience.

• #79 Head lice infestations: A clinical update | Canadian Paediatric Society

  https://cps.ca/documents/position/head-lice

  Head lice (Pediculus humanus capitis) infestations are not a primary health hazard or a vector for disease, but they are a societal problem with substantial costs. […] Head lice are wingless, 2 mm to 4 mm long (as adults), six-legged, bloodsucking insects that live on the human scalp. […] The head louse feeds every 3 to 6 hours by sucking blood, injecting saliva simultaneously. […] Itching occurs if the individual with lice becomes sensitized to antigenic components in the saliva injected as the louse feeds. […] An infestation with lice is called pediculosis and usually involves less than 10 live lice. […] The role of fomites in transmission is controversial. […] Definitive diagnosis of head lice infestation requires the detection of a living louse. […] Because head lice move quickly, their detection requires a degree of expertise and experience.

• #80 Head lice infestations: A clinical update | Canadian Paediatric Society

  https://cps.ca/documents/position/head-lice

  Head lice (Pediculus humanus capitis) infestations are not a primary health hazard or a vector for disease, but they are a societal problem with substantial costs. […] Head lice are wingless, 2 mm to 4 mm long (as adults), six-legged, bloodsucking insects that live on the human scalp. […] The head louse feeds every 3 to 6 hours by sucking blood, injecting saliva simultaneously. […] Itching occurs if the individual with lice becomes sensitized to antigenic components in the saliva injected as the louse feeds. […] An infestation with lice is called pediculosis and usually involves less than 10 live lice. […] The role of fomites in transmission is controversial. […] Definitive diagnosis of head lice infestation requires the detection of a living louse. […] Because head lice move quickly, their detection requires a degree of expertise and experience.

• #81 Patient education: Head lice (Beyond the Basics) – UpToDate

  https://www.uptodate.com/contents/head-lice-beyond-the-basics

  Head lice are usually spread from one person to another through casual contact. […] Some people feel itching or skin irritation of the scalp, neck, and ears. This is caused by a reaction to lice saliva, which the lice inject into the skin during feeding. […] Finding eggs (nits) without lice does not necessarily mean that there is an active infestation; nits can be found for months after lice are treated. […] A topical insecticide (pediculicide) is a substance, usually a lotion or gel, that is applied to the scalp to kill lice. […] Dimethicone is thought to work by coating the lice and disrupting their ability to manage water. […] Studies have examined lotions and other materials (olive oil, butter, mayonnaise, petroleum jelly [Vaseline]) that are applied to the head, and then allowed to dry, with the goal of suffocating lice. However, lice are difficult to suffocate; wet-combing probably works as well and is less messy.

• #82 Lice – Dermatologic Disorders – Merck Manual Professional Edition

  https://www.merckmanuals.com/professional/dermatologic-disorders/parasitic-skin-infections/lice

  Head lice are transmitted by close contact; body lice are transmitted in cramped, crowded conditions; and pubic lice are transmitted by sexual contact. […] Head lice are easily transmitted from person to person with close contact (as occurs within households and classrooms) and may be ejected from hair by static electricity or wind; transmission by these routes (or by sharing of combs, brushes, and hats) is likely but unproved. […] Diagnosis of head lice depends on demonstration of living lice. […] Initial treatment of head lice with topical pediculicides is outlined in the table Initial Treatment Options for Lice. […] Most pediculicides also kill nits. […] Termination or removal of live (viable) nits is important in preventing reinfestation; live nits fluoresce on illumination with a Wood lamp.

• #83 Head lice infestations: A clinical update | Canadian Paediatric Society

  https://cps.ca/documents/position/head-lice

  An increasing resistance of head lice to pyrethrins, permethrin and lindane has been reported. […] If two permethrin applications 7 days apart do not eradicate live lice, consider administering a full treatment course using a medication from another class. […] The scalp may be itchy after applying a topical insecticide but itching does not indicate treatment resistance or a reinfestation.

• #84 Head Lice

  https://www.michigan.gov/emergingdiseases/home/head-lice

  Head lice are tiny (about the size of a sesame seed), wingless parasitic insects that must live on a person (usually on the scalp) to survive. […] They survive by piercing the skin to feed on blood and are almost exclusively associated with hair on the neck and scalp. […] Symptoms of head lice including scabs, scars, and nits. […] Itching (pruritis): Caused by an allergic reaction to lice bites. When lice feed, they inject a small amount of saliva into the skin. Over time, the host can develop an immune reaction to the saliva which results in inflammation and itching. […] The standard for identifying head lice is finding a live louse on the head. […] Treatment should be considered only if lice or viable eggs are observed. […] Generally, a combination of pediculicides (lice medications or shampoos) and nit combing is the most effective.

• #85 Head lice infestations: A clinical update | Canadian Paediatric Society

  https://cps.ca/documents/position/head-lice

  An increasing resistance of head lice to pyrethrins, permethrin and lindane has been reported. […] If two permethrin applications 7 days apart do not eradicate live lice, consider administering a full treatment course using a medication from another class. […] The scalp may be itchy after applying a topical insecticide but itching does not indicate treatment resistance or a reinfestation.

• #86

  https://bpac.org.nz/2017/dimethicone.aspx

  Lice are unlikely to develop resistance to dimethicone lotion as it is not an insecticide and instead kills lice by suffocation. […] Dimethicone is not an insecticide. It kills lice by suffocation and disrupting their ability to regulate water. Products with this mechanism of action may become the preferred treatment for head lice as it is unlikely lice will develop resistance, which can occur with insecticide-based treatments. […] Dimethicone is derived from silicone oil. It is not an insecticide, but eradicates adult and nymph lice via disruption of water homeostasis and suffocation. Due to the mechanism of action of dimethicone, it is thought to be highly unlikely that lice will develop resistance. This may make it a preferable treatment option to insecticide-based treatments, to which lice can develop resistance.

• #87 Head Lice: An Under-Recognized Tropical Problem in: The American Journal of Tropical Medicine and Hygiene Volume 97 Issue 6 (2017)

  https://www.ajtmh.org/view/journals/tpmd/97/6/article-p1636.xml

  There is increasing resistance to pyrethroids and malathion, the most commonly used first-line topical agents. More recently, both oral and topical ivermectin have shown promise for treating head lice, but access to these drugs to treat head lice is nonexistent in low-income settings. Mass treatment of scabies, onchocerciasis, or lymphatic filariasis might have an impact on head lice although data specifically examining this hypothesis are lacking, and there is a risk that resistance to ivermectin might develop.

• #88 Head lice | UMN Extension

  https://extension.umn.edu/biting-insects/head-lice

  Head lice do not jump or fly. […] Adult females attach eggs to individual hairs close (within 1/4 inch) to the scalp, especially behind the ears and on the nape of the neck. […] Young head lice (called nymphs) feed daily on blood and develop into adults in about 9 to 12 days. […] Adults live for about 30 days. […] There is pesticide resistance: Resistance is when a pesticide no longer kills head lice. […] Resistance can be a problem with products containing permethrins (Nix) or pyrethrins (Rid).

• #89

  https://dph.illinois.gov/topics-services/diseases-and-conditions/diseases-a-z-list/diseases/head-lice.html

  Head lice depend completely on their host for nourishment; their only source of food is human blood. […] The life span of an adult louse on a host ranges up to 30 days. During this time, the female head louse can deposit about 90 eggs. After incubating for seven to 10 days, the nits hatch and, after another 10 days, mature into adult head lice and the cycle begins again. […] Objects that are able to harbor head lice and serve as vehicles of transmission should be treated.

• #90 Lice – Dermatologic Disorders – Merck Manual Professional Edition

  https://www.merckmanuals.com/professional/dermatologic-disorders/parasitic-skin-infections/lice

  Controversy surrounds the need to clean the personal items of people with lice or nits and the need to exclude children with head lice or nits from school; there are no conclusive data supporting either approach. […] Treatment of pubic lice is outlined in the table. Initial treatment is typically with topical pediculicides. Oral ivermectin is sometimes used for patients with pubic lice infestation that is refractory to topical therapies.

• #91 Pediculosis – StatPearls – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK470343/

  Malathion 0.5% is an organophosphate cholinesterase inhibitor that causes respiratory paralysis in arthropods. […] Lindane 1% is an organochloride that kills lice by respiratory paralysis. […] Benzyl alcohol 5% lotion was approved in 2009 as a topical suffocation treatment that prevents lice from closing their respiratory spiracles. […] Spinosad 0.9% is a topical pediculicidal agent that was approved in 2011. It works by provoking hyperexcitation, causing death by paralysis. […] Topical ivermectin 0.5% lotion increases chloride in muscle cells, causing hyperpolarization and paralysis. […] The only currently used oral treatment for pediculosis is ivermectin. Ivermectin also has a risk of neurotoxicity. […] Body lice are eradicated through proper hygiene, laundering, or insecticide application to affected clothing. […] Frequent lice treatment is also known to cause severe itching, which can lead to skin breakdown and secondary bacterial infections.

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