Parasites: lice, scabies, worms, and household control

Parasites are rarely the most dramatic emergency in a prolonged scenario, but they are among the most reliably disabling — and the most reliably overlooked. Lice and scabies spread silently through shared bedding, helminth eggs persist in soil and unwashed hands, and every infestation that goes untreated creates an outbreak cycle that keeps restarting. Effective control requires three things working together: treat the affected person, treat all household contacts simultaneously, and decontaminate the environment. Skip any one of those three and you will be treating the same infestation again in three weeks.

Educational use only

This page provides general educational information for emergency preparedness scenarios when professional medical care is unavailable. It is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of a qualified healthcare provider. Use this information at your own risk.

Before you start

Materials: Permethrin 5% cream (scabies treatment); permethrin 1% lotion or pyrethrin shampoo (pediculicide for lice); fine-toothed lice comb; albendazole 400 mg tablets OR mebendazole 100 mg tablets (deworming); praziquantel 600 mg tablets (tapeworm); pyrantel pamoate suspension (pinworm alternative); nitrile gloves. Hot water and a dryer for bedding and clothing. Bleach (1:10 dilution for hard surfaces). See medical stockpiling for stocking guidance.

Permethrin 5% safety thresholds: Approved for use in adults, children ≥ 2 months of age, and (as category B) in pregnancy per CDC scabies clinical guidance. For infants younger than 2 months, sulfur ointment (6–10%) is the alternative; use only under clinician guidance.

Deworming age thresholds: Mebendazole and albendazole are approved by the American Academy of Pediatrics (AAP) for children aged ≥ 2 years. For children under 2 years with suspected helminth infection, consult a clinician or use pyrantel pamoate (≥ 2 months) as an alternative.

Cooking temperatures for tapeworm prevention: Beef, pork, and fish 145°F (63°C) with a 3-minute rest; poultry 165°F (74°C) per USDA FSIS.

Time: Permethrin 5% application: 15–20 minutes active; leave on 8–14 hours before washing off. Lice combing alternative: 20–30 minutes per session, every 2–3 days × 2 weeks. Environmental decontamination: 30–60 minutes for bedding and clothing laundry.

Action block

Do this first: Apply permethrin 5% cream from the neck down (entire body including scalp, neck, palms, and soles in infants and young children) on the affected person and all household and intimate contacts simultaneously (active time: ~20 minutes per person). Time required: Active: 20 min application; wait: 8–14 hours before washing off; repeat treatment at 7 days; environmental laundry 30–60 min. Cost range: Inexpensive for permethrin 1% (lice) and pediculicide shampoo; affordable for permethrin 5% cream and albendazole supply. Skill level: Beginner — head-to-toe application, lice combing, and deworming require no clinical training. Tools and supplies: Permethrin 5% cream; permethrin 1% lotion or pyrethrin shampoo; fine-toothed lice comb; albendazole 400 mg or mebendazole 100 mg; praziquantel; nitrile gloves; large plastic bags for non-washable items. Safety warnings: See Crusted scabies requires isolation below — heavily crusted lesions in immunocompromised patients are highly contagious and require oral ivermectin plus contact isolation.

Pathogen classes covered here

This page focuses on two groups of parasites that are manageable in austere household settings.

Ectoparasites — organisms that live on or in the skin surface: lice (head, body, pubic), scabies mites, and bed bugs. Covered in full below.

Helminths (intestinal worms) — multicellular worms that infect the GI tract: pinworm, roundworm (Ascaris), hookworm, whipworm, and tapeworms. Covered in full below.

Intestinal protozoa — single-celled GI parasites including Giardia and Cryptosporidium — these produce the watery diarrhea syndrome and are covered in full in diarrhea.md, which contains the ORS protocols and antiprotozoal treatment decisions relevant to those organisms.

Blood and tissue parasites — Plasmodium (malaria) and Babesia are beyond the scope of austere household management. Babesia is a tick-transmitted parasite covered in tick-bites.md. Malaria prevention and treatment require travel-medicine knowledge and prescription agents not covered here.

Lice (Pediculus humanus)

Three species of louse infest humans. They differ in habitat and disease significance but share the same basic treatment approach: kill the louse on the person and kill or remove the louse in the environment.

Head lice (P. h. capitis)

Presentation: Intense scalp itch, especially at the nape of the neck and behind the ears. Nits (eggs) are glued to individual hair shafts within 1/4 inch (6 mm) of the scalp — this location is diagnostic, because dandruff and hair casts slide freely while nits do not. Live adult lice are fast-moving and rarely visible during inspection; nits are the reliable sign.

Treatment per CDC:

  1. Apply permethrin 1% lotion (over-the-counter) OR pyrethrin-based shampoo to dry hair. Saturate hair and scalp thoroughly. Leave on for 10 minutes, then rinse with warm water.
  2. Repeat treatment in 9–10 days. The first treatment kills live lice but does not reliably kill all eggs; the second treatment targets nymphs that hatched after the first dose.
  3. Alternative: topical ivermectin 0.5% lotion (now available OTC; FDA-approved for ages ≥ 6 months) applied to dry hair, left for 10 minutes, then rinsed. A single application is usually sufficient — ivermectin lotion is not directly ovicidal but lice that hatch from treated eggs die within ~48 hours; per CDC, retreatment should not be performed without first consulting a clinician.
  4. Wet-combing with a fine-toothed lice comb every 2–3 days for 2 weeks is an effective non-chemical alternative — especially appropriate for children under 2, pregnant women, or when medication resistance is suspected.
  5. Treat all household contacts who are also infested. Prophylactic treatment of non-infested contacts is not recommended; inspect contacts and treat only if lice or nits are found.

Environment: Wash all bedding, hats, scarves, and combs used in the past 2 days in hot water (130°F / 54°C) and dry on the hot cycle for at least 20 minutes. Items that cannot be washed — plush toys, helmets, upholstered furniture — seal in a plastic bag for 2 weeks. Lice cannot survive more than 1–2 days off a human host.

Field note

Lice resist pediculicides at increasing rates in the US. If permethrin fails after two properly timed doses, the population may be resistant. Switch to an alternative agent (ivermectin lotion, spinosad, or benzyl alcohol) — not to a higher concentration of the same drug.

Source: CDC Lice — Treatment (Tier 1).

Body lice (P. h. corporis)

Body lice live and lay eggs in the seams of clothing, not on skin. They feed on the host but return to clothing. This distinction makes them both easy to treat and clinically significant — body lice are the only human louse species that transmits disease, serving as the vector for typhus (Rickettsia prowazekii), trench fever (Bartonella quintana), and relapsing fever (Borrelia recurrentis). In austere, crowded, or low-hygiene scenarios, body lice outbreaks signal elevated risk for these systemic infections.

Treatment: Improved hygiene is the primary treatment. Launder all clothing and bedding in hot water (130°F / 54°C) with a hot-dryer cycle, or seal in a plastic bag for 2 weeks. Pediculicide applied to the skin may be added if the person cannot immediately access clean clothing and laundry. Screen for signs of typhus (high fever, headache, rash spreading from trunk) if the infestation is significant.

Pubic lice (Pthirus pubis — "crabs")

Pubic lice infest coarse hair in the pubic region, underarms, eyebrows, and eyelashes. Presentation is intense itch. Treatment follows the same protocol as head lice: permethrin 1% or pyrethrin applied to the affected area, left 10 minutes, rinsed, repeated in 9–10 days. Screen for other sexually transmitted infections when pubic lice are present.

Source: CDC Lice (Tier 1).

Scabies (Sarcoptes scabiei)

Scabies is caused by a microscopic mite that burrows into the upper skin layer. Transmission is through prolonged direct skin contact — not brief handshakes, but extended contact with an infested person's skin or their recently used bedding. In crowded group-living scenarios, scabies spreads rapidly if the index case is not identified promptly.

Presentation: Intense itch that is characteristically worse at night. Papular rash with small red bumps. Classic locations in adults and older children: finger webs, wrist flexors, axillae, beltline, waist, buttocks, and genitals. In infants and elders, the rash may also involve the scalp, palms, and soles — distribution that would be atypical in a healthy adult.

A classic sign is burrows — thin, wavy, grayish lines 5–15 mm (about 1/4–1/2 inch) long in the skin, most visible in finger webs and wrist flexors.

Incubation: 2–6 weeks from first exposure to symptom onset in a person who has never had scabies. In someone who has had scabies before, symptoms appear within 1–4 days of re-exposure. This long incubation is why simultaneous household treatment is non-negotiable — asymptomatic contacts are already infested.

Treatment per CDC:

  1. Apply permethrin 5% cream from the neck down to the soles of the feet in adults (entire body including scalp, neck, and soles in infants and young children). Massage cream into all skin folds, under fingernails, and between toes.
  2. Leave the cream on for 8–14 hours (overnight application is practical), then wash off thoroughly.
  3. Repeat the treatment in 7 days to catch mites that survived the first application.
  4. Alternative: Oral ivermectin 200 µg/kg as a single dose, repeated in 7–14 days per CDC. Preferred for crusted scabies or when topical treatment is impractical (large household, mobility-limited patient). Ivermectin is prescription-only in the US; stock should be part of a prepared medical supply.

Critical rule: Treat ALL household members and intimate contacts simultaneously, even those without symptoms. Failure to treat asymptomatic contacts simultaneously is the single most common reason scabies re-infestations cycle for months.

Environment: Wash all clothing and bedding used in the last 3 days in hot water (130°F / 54°C) plus hot-dryer cycle. Non-washable items should be sealed in a plastic bag for 72 hours — scabies mites cannot survive more than 2–3 days off a human host.

Post-treatment itch: Itching may persist for 2–4 weeks after successful treatment. This is an immune reaction to dead mites and mite debris, not evidence of treatment failure. Manage with hydroxyzine 25 mg or diphenhydramine 25 mg at night (caution: sedation). A mid-potency topical steroid (hydrocortisone 1–2.5%) applied to itchy areas also helps.

Crusted scabies requires isolation

Crusted (Norwegian) scabies occurs in immunocompromised individuals — the host mounts an inadequate immune response, allowing thousands of mites to accumulate in thick crusted plaques on the skin. These plaques shed enormous numbers of mites and are highly contagious even through brief contact. A person with widespread thick crusting, scaling plaques (not typical papular rash) in any setting must be isolated immediately, treated with combined oral ivermectin plus topical permethrin, and evacuated to a clinician as soon as possible.

Source: CDC Scabies — Treatment (Tier 1).

Bed bugs (Cimex lectularius)

Bed bugs are flat, brown, wingless insects about 5–7 mm (about 1/4 inch) long — roughly the size of an apple seed. They feed on blood at night, are not disease vectors in most settings, and are primarily a quality-of-life and outbreak-spread problem rather than a medical emergency.

Signs of infestation: Bites appearing in clusters or lines on exposed skin (face, neck, arms). Blood spots on sheets and pillowcases. Dark fecal spots in mattress seams, box springs, and bed frames. Visible bugs in seams and crevices — they shelter in any crack within 5–8 feet (1.5–2.4 m) of where a person sleeps.

Treatment of bites: Symptomatic only. A mild topical steroid reduces itch. Antihistamine for systemic itching.

Eradication is the real challenge and requires a systematic approach:

  1. Vacuum all mattress seams, box spring seams, and floor cracks. Dispose of vacuum bag immediately in a sealed plastic bag outdoors.
  2. Wash all bedding in hot water (130°F / 54°C) plus hot-dryer cycle.
  3. Encase mattress and box spring in zippered bed-bug-proof covers, which trap any remaining bugs and prevent re-entry.
  4. Apply food-grade diatomaceous earth along baseboards and in cracks — it physically damages the exoskeleton of insects that crawl through it.
  5. Professional pest control with residual insecticides is the most reliable eradication method when available.

Single treatment is almost never sufficient. Bed bug populations survive in wall voids, electrical outlets, and furniture away from the bed, and eggs are insecticide-resistant. Plan for 2–3 treatment cycles before declaring a space clear.

Source: CDC Bed Bugs (Tier 1).

Helminths — intestinal worms

Helminth infections are far more common globally than most people in high-income countries realize. In a prolonged off-grid or austere scenario — particularly one with degraded sanitation, bare-foot outdoor activity, or compromised food safety — these infections become a genuine household concern.

Pinworm (Enterobius vermicularis)

The most common helminth infection in the United States, and the one most likely to appear in any group-living scenario. Pinworms are highly contagious through the fecal-oral route; eggs survive on surfaces and under fingernails for hours.

Presentation: Intense anal itch, worst at night (when female worms migrate to the perianal area to deposit eggs). Often asymptomatic in adults. In children, sleep disruption and irritability from nocturnal itch.

Diagnosis — tape test: In the early morning, before the child bathes or defecates, press a strip of clear transparent tape firmly to the perianal skin. Attach tape to a glass slide or the inside of a plastic bag. Hold it up to light or examine under low magnification — pinworm eggs appear as clear oval shapes roughly 50 × 25 µm.

Treatment per CDC:

  1. Mebendazole 100 mg as a single oral dose, repeated in 2 weeks. OR
  2. Albendazole 400 mg as a single oral dose, repeated in 2 weeks. OR
  3. Pyrantel pamoate 11 mg/kg (max 1 g) as a single oral dose, repeated in 2 weeks. Available over the counter.
  4. Treat the entire household simultaneously with the same agent and schedule — all infected, symptomatic or not.

Environmental control: Wash all bedding and underwear in hot water on the day of treatment. Keep fingernails trimmed short. Emphasize handwashing before food preparation and after toilet use. Encourage showering rather than bathing to avoid re-ingesting eggs during bath water contact.

Source: CDC Pinworm — Treatment (Tier 1).

Roundworm (Ascaris lumbricoides)

The most prevalent human helminth infection worldwide, transmitted by ingesting eggs from soil contaminated with human feces. Common in areas with poor sanitation.

Presentation: Light infections are often asymptomatic. Heavier infections cause intermittent abdominal pain, nausea, and bloating. The first warning sign may be seeing a large pinkish-white worm (up to 12 inches / 30 cm) passed in the stool. Very heavy infections can cause intestinal obstruction — sudden severe abdominal pain, distension, vomiting, and inability to pass gas — which is a surgical emergency requiring evacuation.

Treatment per CDC:

  • Albendazole 400 mg as a single oral dose. OR
  • Mebendazole 500 mg as a single oral dose (or 100 mg twice daily × 3 days).

No retreatment is needed for light infections if the environment is controlled. Repeat if re-exposure is ongoing.

Source: CDC Soil-Transmitted Helminths (Tier 1).

Hookworm (Necator americanus, Ancylostoma duodenale)

Hookworm larvae penetrate skin directly — usually through bare feet walking on contaminated soil or sand. Once inside, they migrate to the small intestine, attach, and feed on blood. Chronic hookworm infection is a leading cause of iron-deficiency anemia in endemic settings.

Presentation: Itchy, raised rash at the skin entry site (ground itch). Then a symptom-free migration phase. Then abdominal pain, fatigue, and, with heavy infection, significant anemia — pallor, weakness, and breathlessness on exertion.

Treatment per CDC:

  • Albendazole 400 mg as a single oral dose (preferred).
  • Mebendazole 500 mg as a single oral dose.
  • Add iron supplementation (ferrous sulfate 325 mg twice daily, taken with food) if anemia is clinically apparent.

Prevention: Wear shoes or sandals whenever walking outdoors in areas with known hookworm risk. Improve latrine separation from food and water sources. Cross-link to hygiene.md for sanitation protocols.

Whipworm (Trichuris trichiura)

Transmitted by the same fecal-oral-soil route as Ascaris. Usually asymptomatic in light infections. Heavy infections cause mucoid diarrhea and, in severe cases, rectal prolapse in children.

Treatment per CDC:

  • Albendazole 400 mg once daily × 3 days. Single-dose albendazole is less effective for whipworm than for other STH species.
  • Mebendazole 100 mg twice daily × 3 days as an alternative.

Tapeworms (Taenia spp., Diphyllobothrium)

Three species commonly infect humans through undercooked meat or fish:

Tapeworm Source Key feature
Taenia saginata (beef tapeworm) Undercooked beef Proglottids (segments) visible in stool
Taenia solium (pork tapeworm) Undercooked pork Also causes cysticercosis (larval cysts in tissues, including brain)
Diphyllobothrium (fish tapeworm) Undercooked freshwater fish May cause vitamin B12 deficiency

Presentation: Most adult tapeworm infections are asymptomatic. The characteristic sign is flat, white, rice-grain or ribbon-like segments (proglottids) passed in the stool or visible at the anus. Abdominal discomfort and vague nausea occur in some patients.

Treatment per CDC:

  • Praziquantel 5–10 mg/kg as a single oral dose for beef and pork tapeworm; 10 mg/kg for fish tapeworm.

Neurocysticercosis — evacuate immediately

Taenia solium can cause cysticercosis when eggs (not larvae from undercooked pork — this is egg ingestion from hand-to-mouth contamination with infected human feces) establish larval cysts in muscle and, critically, in the brain (neurocysticercosis). Symptoms include new seizures, focal neurological deficits, or severe headache in someone with known exposure to T. solium or travel to an endemic region. This is a neurological emergency requiring CT scan, specialist treatment, and evacuation. Do not attempt field praziquantel treatment without imaging — killing cysts in the brain without anti-inflammatory cover can worsen inflammation.

Source: CDC Tapeworm (Taeniasis) (Tier 1).

When to suspect parasites in a prolonged scenario

The following presentations should trigger parasite consideration — not as the first diagnosis, but as part of the differential when first-line treatments for more common conditions are failing.

Suspect ectoparasites when: - Intense itch is worst at night with a distribution matching lice or scabies (finger webs, wristlines, waistline). - Multiple household members develop itch within weeks of each other. - Visible insects, nits on hair shafts, or burrow lines are present on inspection. - Bites appear in clusters or lines on exposed skin.

Suspect helminths when: - Unexplained iron-deficiency anemia without obvious blood loss (hookworm). - Persistent vague abdominal symptoms in someone with bare-foot soil exposure. - Anal itch in a child or anyone in the household — tape-test first. - A visible worm or ribbon-like segment appears in the stool. - A child is failing to gain weight despite adequate food intake with chronic abdominal complaints. - History of eating undercooked beef, pork, or fish in a resource-limited setting.

Refer to diarrhea.md when: - Symptoms are primarily watery, persistent diarrhea, bloating, and gas — particularly if onset follows contaminated water exposure — which is the primary presentation of Giardia and Cryptosporidium, the intestinal protozoa covered in diarrhea.md.

Household control — the linchpin of parasite management

Individual treatment without household control is treatment failure on a delay. The following steps apply across all the ectoparasites and helminths on this page.

Simultaneous treatment of all household contacts: - For lice: treat all infested members on the same day. Inspect non-infested members and treat if found to have lice or nits. - For scabies: treat ALL household and intimate contacts simultaneously, regardless of symptoms. The 2–6 week incubation means asymptomatic contacts are already infested. - For pinworm: treat all household members simultaneously, symptomatic or not. - For hookworm and other soil-transmitted helminths in endemic areas: treat all children and adults with confirmed or probable exposure.

Hot washing for bedding and clothing: Wash all bedding, towels, and clothing worn or slept in during the past 3 days at 130°F (54°C) or above, and dry on a hot cycle for at least 20 minutes. This temperature reliably kills lice, scabies mites, and helminth eggs on fabric. Lower temperatures may reduce counts but not eliminate them.

Non-washable items: Seal items that cannot be laundered in a sealed plastic bag. For scabies: 72 hours minimum. For lice: 2 weeks. For bed bugs: 30+ days.

Surface cleaning: A 1:10 bleach solution (approximately 5,000 ppm chlorine — roughly 1 cup of standard bleach per 9 cups of water) on hard surfaces is effective for helminth egg decontamination. Apply and allow 5 minutes of contact before wiping.

Handwashing: Soap and water for 20 seconds after every toilet visit and before all food contact. Handwashing is the single most effective break in the fecal-oral transmission cycle for pinworm, roundworm, and whipworm.

Sanitation: In off-grid settings, proper siting of latrines at least 100 feet (30 m) from any water source and downslope from garden areas prevents helminth egg contamination of food and drinking water. See hygiene.md for latrine siting and water for water protection protocols.

Footwear: Wearing shoes or sandals at all times when walking outdoors in soil — especially in areas where sanitation is compromised — prevents hookworm and some Ascaris exposure. This is not optional in endemic or compromised-sanitation scenarios.

Cooking temperatures: Cook all meat to safe internal temperatures to prevent tapeworm infection. Per USDA FSIS: beef, pork, and fish to 145°F (63°C) with a 3-minute rest; poultry to 165°F (74°C). See food/storage.md for food-safety cross-reference.

Pediatric and pregnancy considerations

Children

Pinworm in children is very common, rarely dangerous, and easily treated. Children are the most frequent index case in household pinworm outbreaks due to hand-to-mouth behavior. Mebendazole and albendazole are approved by the American Academy of Pediatrics for children aged 2 years and older. For children under 2 years, pyrantel pamoate (available over-the-counter, dosed at 11 mg/kg) is an alternative.

Permethrin 5% cream is safe for scabies treatment in children 2 months of age and older. For infants under 2 months, sulfur ointment (6%) is the alternative — but requires clinician guidance for concentration and application.

Lice treatment with permethrin 1% lotion is FDA-approved for children 2 months of age and older. Pyrethrin shampoos are generally labeled for children 2 years and older. Topical ivermectin 0.5% lotion is approved for ≥ 6 months. For infants under 2 months, wet-combing every 2–3 days for 2 weeks is the preferred non-chemical approach.

Field note

Children with pinworm almost always have itching only at night. A useful quick test: check the perianal area with a flashlight at night 2–3 hours after the child falls asleep — you may see worms moving. This costs nothing and can replace the tape test when supplies are limited.

Pregnancy

Permethrin 5% cream: Considered safe in pregnancy (FDA Pregnancy Category B); cleared for scabies and lice treatment per ACOG and CDC guidance.

Pyrethrin (lice shampoo): Considered safe in pregnancy based on limited absorption and favorable safety profile.

Ivermectin (oral or topical): Limited safety data in pregnancy. CDC recommends reserving oral ivermectin for severe cases (crusted scabies) where topical permethrin is not feasible. Do not use as first-line in pregnancy.

Mebendazole: Avoid in the first trimester (animal teratogenicity data). Use in the second and third trimesters is acceptable for symptomatic helminth infections per CDC and WHO guidance when the risk of untreated infection outweighs the theoretical medication risk.

Albendazole: Second-line in pregnancy; WHO-endorsed for use in the second and third trimesters for mass-drug-administration programs in endemic areas when the benefit outweighs risk. Avoid in the first trimester.

Praziquantel (tapeworm): Cleared by WHO for use in pregnancy when treatment of tapeworm infection is indicated.

For any helminth treatment in the first trimester, defer to the second trimester when possible, or treat only if the infection is symptomatic and untreated risk is significant.

Common mistakes that prolong infestations

Treating only the symptomatic person. Scabies, lice, and pinworm spread to household contacts before symptoms appear. Treating one person while others remain untreated guarantees re-infestation within weeks.

Skipping the second dose. Permethrin and pediculicides kill live insects but often do not eliminate all eggs. Eggs hatch 7–10 days after treatment. The repeat dose at that interval is what closes the gap.

Inadequate environmental decontamination. Retreating a patient who returns to an infested bed or clothing causes treatment to fail regardless of medication dose. Environmental control and medication go together.

Confusing post-scabies pruritus with treatment failure. Itch that persists 2–4 weeks after a successful course of permethrin 5% is immune-mediated — it is not evidence of surviving mites. Repeating treatment unnecessarily adds drug exposure without benefit. Use antihistamines and topical steroids for residual itch.

Walking barefoot in soil or sand in any compromised-sanitation area. Hookworm larvae penetrate intact skin. Shoes are the only effective prevention.

Treating suspected worms with random remedies (garlic, diatomaceous earth taken internally, black walnut hull). These have no evidence base for helminth treatment. Use evidence-based antihelmintics at the correct dose.

Missing crusted scabies in an immunocompromised household member. The heavy mite burden and shed crusts will re-infest all household contacts despite individual treatment. Identify and escalate this presentation before it becomes an outbreak.

Treating bed bug bites medically without addressing the bed bugs. The bites will recur every night until the source is eliminated. Symptomatic treatment of bites without eradication is not treatment — it is temporary relief.

Teach your family — seven rules

When one person in a household has a parasite, the household is the unit of treatment. These rules apply to every member, child and adult alike.

  1. Tell the adult if you have persistent itching, anal itching at night, or see a worm or white segment in the toilet. Early identification of an index case stops an outbreak.
  2. Do not share combs, hats, towels, pillows, or bedding with anyone being treated for lice or scabies.
  3. Wash all bedding, towels, and clothing in HOT water plus a hot dryer the day treatment begins. Not warm — hot. 130°F (54°C) is the target.
  4. Everyone in the house gets treated the same day. Not one person, not the two who are itching — everyone. The person who isn't itching yet is the vector for re-infestation.
  5. Wear shoes outside. In any setting with compromised sanitation, bare feet in soil or sand are how hookworm enters the body.
  6. Wash hands with soap before every meal and after every toilet visit. This breaks the fecal-oral transmission cycle for pinworm, roundworm, and whipworm.
  7. Two doses, not one. Whatever the treatment is, the second dose at 7–14 days is not optional — it catches what the first dose missed.

Sources and next steps

Last reviewed: 2026-05-22

Source hierarchy:

  1. CDC Scabies — Treatment (Tier 1, CDC clinical guidance — permethrin 5%, ivermectin dosing, household treatment protocol)
  2. CDC Soil-Transmitted Helminths (Tier 1, CDC — albendazole/mebendazole dosing for Ascaris, hookworm, whipworm)

Legal/regional caveats: Ivermectin (oral) and praziquantel are prescription-only in the United States; albendazole is prescription-only. Permethrin 1% lotion and pyrethrin shampoos are over-the-counter for lice. Permethrin 5% cream for scabies requires a prescription in most US states. Pyrantel pamoate (pinworm) is over-the-counter. Medical scope-of-practice limits apply — if a clinician is accessible, confirm treatment and dosing before proceeding independently.

Safety stakes: high-criticality topic — recommended to verify thresholds before acting.

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