Scabies, lice and other ectoparasites

• Scabies and lice are infestations of the skin and hair by tiny arthropods that live on human body surfaces and feed on blood or skin.
• Neither is a sign of poor hygiene. Scabies occurs through prolonged skin-to-skin contact and can infest anyone; head lice spread mainly by head-to-head contact and are common in school-aged children.
• Scabies announces itself as intense itch that is worse at night, with burrows or papules in skin folds and around the fingers, wrists and genitalia; crusted scabies in frail or immunosuppressed people is intensely contagious.
• Head lice are diagnosed only by finding a live louse; nits alone are not proof of active infestation.
• Permethrin and ivermectin are the two first-line treatments for scabies; head lice are treated with wet combing, a physical insecticide such as dimeticone, or malathion where appropriate, with household contacts treated on the same day.
• Outbreaks in institutions are controlled by early case finding, treating all contacts, short periods of contact precautions, and environmental steps rather than fumigation.

By the end of this page you should be able to:

1. Explain what scabies and lice are, how they spread and how they differ clinically.
2. Recognise classic scabies, crusted scabies and head lice, including their typical distribution and complications.
3. Apply a reliable diagnostic approach, knowing when skin scraping or detection combing is needed and when it is not.
4. Prescribe permethrin and ivermectin correctly: dose, route, frequency, age and pregnancy cautions.
5. Manage head lice with wet combing and topical agents and know which approaches do not work.
6. Lead or support an outbreak response in a residential, hospital or educational setting.
7. Adapt diagnosis and treatment for pregnancy, infants, immunocompromised and older adults, and for low-resource settings.

Scabies is an infestation of the skin by the human itch mite Sarcoptes scabiei var. hominis, a 0.3 to 0.5 millimetre mite that burrows into the epidermis and tunnels through the stratum corneum (the outermost layer of skin).^[7] This mite is specific to humans. An average of 10 to 15 mites live on an infested person in the classic form.^{[6][7] [5]}

Two clinical forms matter most:

• Classic (typical) scabies. A low-grade infestation with a few, usually 5 to 15, mites per host, producing intense nocturnal itch and a burrow or papular rash in characteristic sites.^[7]
• Crusted scabies (formerly Norwegian scabies). A hyperinfestation in which thousands to millions of mites infest thick, crusted, scaling plaques. It occurs in people with impaired immunity or sensation, it is intensely contagious, and it drives outbreaks.^[2][6][7]
• Nodular scabies. Persistent, intensely itchy nodules, often in the axillae, groin and genital skin, that can continue for weeks after the mites have been killed.^[7]

Head lice, Pediculus humanus capitis, are wingless, blood-feeding insects 2 to 3 millimetres long that infest scalp hair. An infestation usually involves fewer than 10 live lice.^[8] Body lice (Pediculus humanus humanus) and pubic lice (Pthirus pubis) belong to the same broad group but occupy different sites and carry different epidemiology; body lice are associated with severe crowding and clothing hygiene.^[7]

Scabies is a global condition, not a disease of poverty alone, although it is heaviest in low-income tropical settings.

• At least 200 million people worldwide are affected at any one time.^[6]
• In resource-poor settings, 5 to 50 percent of children are affected.^[6]
• Prevalence is bimodal by age: children and older adults are most often affected, with adolescents having high rates in some datasets.^[7]
• In endemic settings, children and older adults are most often affected, and crusted scabies concentrates in people with immunosuppression, reduced ability to scratch, neurological disorders and older age.^[6][7]
• Crusted scabies concentrates in people with immunosuppression (such as HIV infection or lymphoma, or long-term corticosteroid use), reduced ability to scratch, learning difficulties or neurological disorders, and older adults.^[7]

Head lice are among the most common paediatric infestations worldwide. They are most common in children aged 4 to 11 years and are more common in girls than in boys.^[8] Head lice occur in all hair types and hair lengths and are not more common in dirty than in clean hair.^[8] Detection combing is more reliable than visual inspection for finding lice.^[8]

Scabies spreads by close contact. The life cycle is short but clinically important:

• The adult female mite tunnels in the stratum corneum and lays about 25 eggs before dying; the life cycle lasts 4 to 6 weeks.^[7]
• Eggs hatch in 3 to 4 days and mature into adults in 10 to 15 days.^{[6][7] [8]}
• Symptoms usually begin 4 to 6 weeks after primary infestation, when the host develops a type IV hypersensitivity reaction to mite proteins and faeces.^[5][6][7] In a reinfested person symptoms appear within 1 to 4 days, because of prior sensitisation.^[5]

How it is acquired

• Classic scabies spreads by prolonged, direct skin-to-skin contact with an infected person; sexual contact is a common route. Brief, casual contact such as a handshake is unlikely to transmit it. Transmission can also occur via shared clothing or bedding, because mites survive an average of 24 to 36 hours away from the host.^[6][7]
• Crusted scabies is far more contagious: mites spread by brief direct contact and readily via bedding, towels, clothing and upholstery, because a patient can carry thousands to millions of mites. Mites from crusted scabies survive up to 7 days off the host.^[2][6][7]
• Scabies is infectious before the rash appears, because of the asymptomatic incubation period.^[6][7]
• Rarely, scabies can be transmitted from dogs (Sarcoptes scabiei var. canis) or cats (Notoedres cati); animal scabies usually produces lesions where skin touched the animal, has no burrows, and is self-limiting.^[7]

Risk factors for classic scabies include close contact with an infested person, poverty and social deprivation, crowded living conditions and institutionalisation, and winter months. Outbreaks occur in nursing homes, long-term care facilities, military barracks, prisons, childcare facilities and homeless shelters. Head lice spread by head-to-head contact; they cannot hop, jump or fly, but crawl rapidly (about 23 centimetres per minute). Transmission via hats, combs or pillows is extremely unlikely, pets do not carry human head lice, and the louse survives only 1 to 2 days off the scalp.^[8]

Scabies. The characteristic damage is immune, not mechanical. The female mite burrows; her eggs and faeces accumulate in the tunnel; and 4 to 6 weeks later the host mounts a delayed type IV hypersensitivity reaction to mite antigens. That immune response produces the itch and rash, which is why first infestation is asymptomatic for weeks. Reinfestation surfaces in 1 to 3 days because of prior sensitisation. In crusted scabies the immune response is attenuated, so the mite burden explodes while symptoms may be mild or absent. Scratching then seeds the skin with bacteria, so secondary infection is common, particularly in tropical settings.^[5][6]

The classic presentation is a person who is itchier at night than during the day, with small papules or burrows in characteristic sites. The itch comes from the hypersensitivity reaction described above.

Key features:

• Itch. Intense, generalised, worse at night. The itch is driven by the host immune response, not by the mite moving.^[5][7]
• Distribution. Papules and burrows favour skin folds and thin skin: between the fingers, the sides of the fingers, the flexor wrists, the elbows, the axillae, the periumbilical area, the waist, the buttocks, the nipples and the genitalia. The back is often spared, and the head is spared except in young children. Palms and soles are involved in infants, young children and older adults.^[7]
• Lesions. The classic lesion is the burrow: a thin, brown-grey, slightly raised or scaly line 0.2 to 1 centimetre long. Burrows are often found between the fingers and at the sides of the fingers. Because scratching and secondary infection destroy them, they can be hard to find, and they may be absent in people who scratch a lot or who have eczema.^[7]
• Nodular scabies. Firm, intensely itchy nodules on the penis, scrotum, groin, axillae and buttocks that can persist for weeks to months after successful treatment. They represent a residual hypersensitivity reaction.^[7]
• Secondary changes. Excoriations, haemorrhagic crusting, eczematisation and impetigo. In severe cases secondary infection can lead to post-streptococcal glomerulonephritis.^[5][6][7]

Time course is diagnostically useful:

• In a person with no previous scabies, symptoms appear 3 to 6 weeks after infestation.^[5][6]
• In a reinfested person, symptoms appear within 1 to 4 days.^[5]
• Crusted scabies often presents with little or no itch, because the immune response is blunted. It shows generalised, poorly defined erythematous, fissured plaques covered in thick scale and crusts, with hyperkeratotic areas on bony prominences such as the knuckles, elbows and iliac crest. The mite burden can be enormous.^[2][6][7]

A vignette: a 24-year-old man has had 3 weeks of generalised itch that is worse at night. His partner has a similar itch. On examination there are small papules in the finger webs and on the flexor wrists, with excoriations on the buttocks. There are no burrows visible, because he has scratched. Skin scraping is possible but often negative, because only a handful of mites are present. The diagnosis is clinical, and his partner and household must be treated at the same time.

Head lice usually cause an itchy scalp, sometimes with visible excoriations at the back of the neck or behind the ears. Infestation is often discovered by a parent or school nurse. Itching can be delayed: a child may be infested for weeks before itching begins, or may never itch at all.

Signs that can be seen:

• Live lice on the scalp, behind the ears or in the occipital region, or crawling on the hair.
• Nits as small, oval, firmly attached specks on the hair shaft near the scalp; nits further than about a centimetre from the scalp are usually empty shells.
• Secondary changes such as occipital lymphadenopathy, impetigo or excoriation from scratching.

Scabies can be mistaken for several other pruritic conditions. The differential rests on history, distribution and (when needed) microscopy.

Crusted scabies in particular can be mistaken for psoriasis, Darier disease, or xerotic dermatitis; the presence of burrows, contact history and mites on microscopy settles it.^[7]

Head lice must be distinguished from nits that are merely empty shells, seborrhoeic scale, hair casts and hair-spray particles. The practical rule is simple: nits and scale alone are not an active infestation. A live louse must be found to confirm it.^[8]

Most diagnoses are clinical, made from history and examination, together with the history of close contacts. Skin scraping microscopy or dermoscopy can confirm but is often not needed, particularly in highly endemic areas.^[6][7]

Two bedside tests exist:

• The ink burrow test. Back or blue ink is applied to a suspected papule and wiped off with alcohol; if scabies is present a dark, zig-zag line appears as ink tracks down the mite tunnel.^[7]
• Skin scraping microscopy. Papules or linear lesions are scraped with a number 15 scalpel blade dipped in liquid paraffin, from several (four or more) sites. The material is examined under a microscope. A mite, egg or mite faeces confirms the diagnosis. The test is 100 percent specific if a mite is seen, but sensitivity is generally under 50 percent, because classically infested people carry only 5 to 15 mites.^[5][7]

A negative scraping therefore does not exclude scabies; a positive one is decisive. In practice, treating on clinical grounds, treating contacts and reassessing at 2 to 4 weeks is the standard primary-care approach.

Because an active infestation requires a live louse, the investigation is detection combing. A plastic fine-toothed comb with teeth 0.2 to 0.3 millimetres apart is more reliable than visual inspection. Wet combing (hair washed, conditioned, detangled, then systematically combed from roots to tips in sections) has a sensitivity of about 91 percent for live lice; dry combing is quicker and almost as good. The whole head takes 10 to 15 minutes wet. Less preparation is needed for dry combing, but wet combing is more accurate. All household members should be checked. ^[8]

The strategy is simple but often executed poorly: treat the index case, treat all contacts, and decontaminate the environment. Failing on contacts is the commonest reason scabies seems to "resist" treatment.

Key principles: treat the affected person and all household members, close contacts and sexual partners, even those without symptoms; treat them at the same time, ideally on the same day; advise decontamination of bedding, clothing and towels (wash at at least 60 degrees Celsius, or seal unwashable items in a plastic bag for at least 72 hours) and vacuuming; explain that itch can persist for up to 4 weeks after successful treatment and does not mean failure; review if new burrows appear or symptoms persist beyond 2 to 4 weeks after the last treatment.^[4][6][7]

Two regimens have similar efficacy and are the first-line options.^[1][6][7]

1. Permethrin 5% cream (topical)

• FDA-approved for scabies in people aged 2 months and older.^[1]
• Apply from the neck down to the entire body, including skin folds, the area under the nails and between the fingers and toes; avoid eyes and mouth. The CKS approach additionally includes the face, neck, scalp and ears.^[7]
• The skin should be cool and dry before application.^[7]
• Leave on for 8 to 12 hours, then wash off (8 hours for infants).^[7]
• One application is often enough, but two or more applications about a week apart may be needed to eliminate all mites.^[1]

2. Ivermectin 200 micrograms per kilogram, by mouth (two doses)

• Two doses of oral ivermectin at 200 micrograms per kilogram per dose, taken with food, 7 to 14 days apart (CKS uses a second dose after 7 days; CDC advises 7 to 14 days apart).^[1][7]
• Ivermectin guidelines recommend taking it on an empty stomach, but scabies experts recommend taking it with a meal to increase bioavailability.^[1]
• Topical permethrin and oral ivermectin have similar efficacy for cure of scabies.^[1]
• Ivermectin is not approved by the FDA for scabies, although ivermectin 3 mg is licensed in the UK for scabies.^[1][7]
• Ivermectin is also on the WHO essential medicines list for scabies.^[6]
• Safety in children weighing under 15 kilograms and in pregnant women has not been established.^[1][6]

Choice between permethrin and ivermectin should be based on the individual clinical situation. Ivermectin is preferred over permethrin when there is pre-existing eczema or other skin conditions that may become hypersensitive to topical agents.^[7]

Alternatives above are from CDC Clinical Care of Scabies.^[1]

Crusted scabies needs both oral and topical therapy, often for prolonged periods.

• Ivermectin 200 micrograms per kilogram per dose given together with topical permethrin. Common expert schedules use 3 doses (days 1, 2, 8), 5 doses (days 1, 2, 8, 9, 15) or 7 doses (days 1, 2, 8, 9, 15, 22, 29), depending on severity.^[1]
• Topical permethrin applied to the whole body together with the oral agent, with no consensus on frequency: expert recommendations range from daily application to application every 2 to 3 days for the first 1 to 2 weeks.^[1]
• A keratolytic cream may be added to reduce crusting.^[1]
• Specialist (dermatology) advice is needed; hospital admission and barrier nursing may be required; investigate underlying immunodeficiency.^[7]
• Crusted scabies is a source of rapid outbreak: contain, notify, and treat contacts early.^[2][6]

• Reassess application technique first: quantity, covering all skin including folds and nails, correct duration, and same-day treatment of contacts. A period of 4 weeks should elapse after ivermectin before full recovery can be assumed.^[7]
• If symptoms persist beyond 2 to 4 weeks after the last treatment, or new burrows appear, retreat and consider oral ivermectin in combination with a topical agent, plus specialist advice.^[7]
• For resistant or refractory scabies, consider combination topical and oral therapy after discussion with a dermatologist.^[7]
• Persistent nodular scabies may need high-potency topical steroids, intralesional steroids, oral steroids, or oral ivermectin, under specialist care.^[7]

Head lice require a confirmed diagnosis (a live louse) before treatment. Once confirmed, three main approaches are used.^[8]

1. Wet combing. Systematic combing of conditioned wet hair with a louse detection comb on days 1, 5, 9 and 13, with a final check on day 17. Two combing procedures are recommended at each session. Wet combing cures about 38 to 52 percent of cases in trials.^[8]
2. Physical insecticides. Silicone or fatty acid ester products that suffocate lice, such as dimeticone 4% gel, lotion or spray. European trials report cure rates of 70 to 92 percent; physical agents are preferred for pregnant or breastfeeding women, children aged 6 months to 2 years, and people with asthma or eczema.^[8]
3. Chemical insecticide. In the UK the only recommended chemical insecticide is malathion 0.5% aqueous liquid, but resistance has been reported and cure rates range from 33 to 75 percent across trials. Shampoo formulations are not recommended, because they are too dilute and have insufficient contact time. Permethrin 1% shampoo is not suitable for head lice because of its licensed method of application.^[8]

Practical dosing and application points: OTC pyrethrins (with piperonyl butoxide) kill live lice only, not unhatched eggs; a second treatment at 9 to 10 days.^[3] Permethrin 1% lotion kills live lice; treat again on day 9; approved from 2 months of age; resistance exists but prevalence is unknown.^[3] Benzyl alcohol 5% kills lice but not eggs; retreat after 7 days; from 6 months of age.^[3] Ivermectin 0.5% lotion kills lice and prevents nymph survival; a single application on dry hair, usually without nit combing; from 6 months of age. Oral ivermectin (200 or 400 micrograms per kilogram, repeated in 9 to 10 days) is effective against head lice but is not for children weighing under 15 kilograms or for pregnant women.^[3] Malathion 0.5% is pediculicidal and partly ovicidal; second treatment after 7 to 9 days if live lice remain; from 6 years of age; flammable.^[3] Spinosad 0.9% kills live lice and unhatched eggs, so retreatment is usually not needed; from 6 months of age; repeat only if live lice are seen at 7 days.^[3] Lindane is no longer available in the US and Canada and is no longer recommended by the American Academy of Pediatrics.^{[3] [8]}

Application advice for insecticides: apply to all dry scalp and hair from roots to tips, leave on for the manufacturer's recommended time (15 minutes to at least 8 hours; 8 to 12 hours overnight for lotions and liquids), and generally treat twice at least 7 days apart. After treatment, check the hair weekly for a month. A small bottle is enough for short hair; longer, thicker hair may need a larger bottle or two. Do not use more than 2 to 3 times with the same medicine if it fails, do not combine insecticides, and rinse topical agents over a sink with warm water to limit skin exposure.^[3][8]

Measures that help prevent reinfestation: treat all affected household members on the same day; check for live lice for a week after treatment; remember that itching can persist for 2 to 3 weeks after successful eradication and does not by itself mean failure; there is no need to wash or fumigate clothing and bedding beyond items in contact with the head in the 2 days before treatment, because lice die within 1 to 2 days off the head. Children being treated can still attend school, and regular detection combing at home is the best way to catch reinfestation early. Essential oil and herbal products are not recommended, because there is no consistent evidence of safety or efficacy.^[8]

Body lice (Pediculus humanus humanus) and pubic lice (Pthirus pubis) are closely related to head lice but occupy different sites. Body lice infest clothing and are seen with severe crowding and poor hygiene; they feed on the body rather than the scalp, and the skin is often excoriated. Pubic lice produce itchy red papules in coarse body hair such as the pubis, axillae, eyebrows and eyelashes and are often sexually acquired. Both are diagnosed by finding the louse and treated with permethrin or other appropriate agents.^[7]

Scabies

• Secondary bacterial infection with Staphylococcus aureus or beta-haemolytic streptococci: impetigo, folliculitis, furuncles, abscesses, cellulitis. Repeated scratching drives this.^[5][6][7]
• Post-streptococcal glomerulonephritis in severe cases; evidence of acute renal damage has been found in up to 10 percent of children with scabies in resource-poor settings.^[5][6]
• In tropical settings scabies-associated skin infection is a common risk factor for rheumatic heart disease through streptococcal infection.^[6]
• Nodular scabies: persistent pruritic nodules for weeks to months after mites are killed.^[7]
• Crusted scabies: life-threatening, with sepsis and secondary invasive infection possible; it is highly contagious.^[2][6]

Head lice

• Pruritus, insomnia, impaired concentration, social stigma, absence from school or work.
• Excoriation of the scalp, occipital or cervical lymphadenopathy and secondary bacterial infection.

Scabies has a good prognosis if compliance with treatment is satisfactory and all close contacts (symptomatic or asymptomatic) are treated at the same time. Itching may continue for up to 4 weeks after successful treatment. Crusted scabies takes longer and needs repeated treatment, and the underlying condition (for example HIV infection or neurological disease) governs outcome.^[6][7]

Head lice cause no serious physical harm; the prognosis is excellent, with most people responding to treatment. Treatment failure arises from incorrect use, inadequate application or exposure time, resistance and reinfestation when household contacts are not examined and treated. Left untreated, head lice can persist for long periods.^[8]

Scabies spreads easily in crowded settings. Classic scabies is usually carried for weeks before treatment; crusted scabies is far worse. Common settings include nursing homes, extended-care facilities, hospitals, detention facilities, childcare settings and shelters for homeless people.^[4][6]

Key institutional steps (from CDC, updated 18 December 2025):^[4]

• Maintain a high index of suspicion for scabies in anyone with an undiagnosed skin rash, even without itch, and screen new patients, residents and staff.
• Screen new residents and employees and train staff to take skin scrapings.
• Avoid skin-to-skin contact with suspected or confirmed patients; use gloves and thorough handwashing for hands-on care.
• Avoid skin-to-skin contact with the infested person for at least 24 hours after effective treatment. ^[4]
• Identify and treat all people who had prolonged direct skin-to-skin contact with the index case before treatment, and offer treatment to household contacts of staff who are being treated.
• Staff can usually return to work the day after a dose of permethrin or ivermectin; symptomatic staff who provide hands-on care may need disposable gloves for several days afterwards. ^[4]
• Decontaminate bedding and clothing by washing with hot water and drying on high heat: temperatures above 50 degrees Celsius (122 degrees Fahrenheit) for 10 minutes kill mites and eggs. Items that cannot be washed can be sealed in a closed plastic bag for several days to a week. ^[2][4]
• Routine cleaning and vacuuming suffice. Environmental pesticide sprays or fogs, discarding mattresses and environmental disinfestation are neither necessary nor warranted.
• Keep records so contacts and staff who have left the institution can be identified and notified; symptoms can take up to 2 months to appear. ^[4]
• Notify the local health department if multiple cases occur and cooperate with neighbouring institutions.

Crusted scabies in particular should trigger institutional infection-control escalation: aggressive treatment of the index case, immediate isolation and barrier nursing, screening and prophylactic treatment of contacts, and notification of local health authorities. Rooms should be cleaned and vacuumed after the patient moves or leaves. In crusted outbreaks, washing at high temperature for 10 minutes above 50 degrees Celsius, sealing unwashable items for up to a week, and thorough room cleaning apply; pesticide sprays and fogging are unnecessary and discouraged, and discarding mattresses is generally unnecessary.^[2]

Scabies is classified as a neglected tropical disease by WHO (since 2017), and ivermectin is on the essential medicines list for scabies. WHO expert consultation in 2019 concluded that mass drug administration can be highly effective where prevalence is 10 percent or greater, with two doses of ivermectin at 200 micrograms per kilogram, or topical permethrin 5% cream when ivermectin is contraindicated or unavailable. Evidence that one dose is enough is still inconclusive. WHO targets for 2030 are to include scabies management in universal health coverage and to run mass drug administration in endemic areas (prevalence 10 percent or greater). WHO works with Member States to integrate scabies control into skin-related neglected tropical disease programmes.^[6]

Pregnancy and breastfeeding. Scabies in pregnancy is usually treated with permethrin 5% cream, because the safety of ivermectin in pregnancy has not been established. Head lice in pregnancy should be managed with wet combing or dimeticone 4% lotion rather than neurotoxic insecticides.^[1][8]

Infants and children. Scabies is rare below 2 months of age; seek specialist advice if treatment is needed at that age. Permethrin 5% cream is licensed from 2 months. Ivermectin is not for children weighing under 15 kilograms. Sulphur ointment is safe in infants under 2 months. Head lice treatments vary by age: pyrethrins from 2 years, permethrin 1% from 2 months, spinosad and benzyl alcohol and ivermectin lotion from 6 months, malathion from 6 years.^[1][3][7]

Older adults. Older adults are at high risk of crusted scabies and are often recognised late. For head lice, lindane is avoided in older adults. Regular skin checks in care homes catch scabies before it becomes crusted.^[4]

Immunocompromised patients (for example people living with HIV, transplant recipients, or those on long-term corticosteroids) are at risk of crusted scabies; they need specialist assessment and combined topical and oral therapy. Head lice cause the same discomfort in these groups, and lindane should be avoided.^[2][7]

Scabies is common where crowding and poverty intersect, and the burden falls on children, with up to 10 percent of children in such settings showing renal damage from secondary infection.^[6] WHO recommends an integrated skin-neglected-tropical-disease approach adapted to the conditions present in each country. Low-cost, widely available options include sulphur ointment for infants, permethrin where available, ivermectin for mass drug administration in highly endemic areas, benzyl benzoate emulsion and supportive management of secondary infection with antiseptics or antibiotics. In settings where skin scrapings or dermoscopy are unavailable, diagnosis remains clinical, and treatment of the index case together with all household contacts remains the cornerstone. Sulfur and benzyl benzoate are WHO-listed topical options.^[6]

• Scabies is an infestation by Sarcoptes scabiei var. hominis; classic disease carries 5 to 15 mites, crusted disease carries thousands to millions.^[6][7]
• Classic scabies: intense nocturnal itch, burrows or papules in skin folds, 10 to 15 mites; incubation 3 to 6 weeks in naive hosts, 1 to 4 days on reinfestation.^[5][6][7]
• Crusted scabies occurs in immunosuppressed or insensate people, is intensely contagious, and can sustain outbreaks.^[2][6][7]
• Head lice are diagnosed only by finding a live louse; nits alone are not proof of active infestation.^[7]
• Permethrin 5% cream is first-line for scabies from 2 months of age; ivermectin 200 micrograms per kilogram by mouth, two doses 7 to 14 days apart, is an equally effective alternative with cautions for under 15 kilograms and pregnancy.^[1][7]
• Head lice: detection combing with 0.2 to 0.3 millimetre teeth; wet combing on days 1, 5, 9 and 13 (check day 17); dimeticone or malathion as topical options with correct contact times.^[3][8]
• Outbreak control in institutions depends on early detection, treating all contacts on the same day, contact precautions for at least 24 hours after treatment, hot washing above 50 degrees Celsius for 10 minutes, and avoidance of environmental spraying.^[4]

This topic is a curriculum gap and is not linked to other MedGrasp topics here. It is intended to connect in future to topics on skin and soft tissue infection, sexually transmitted infections, paediatric dermatology, infection control in facilities, and drug topics on permethrin and ivermectin.