By Gary M. White, MD
Pediculosis capitis represents infestation of the scalp by the louse Pediculosis humanis.
- Head lice die in one or two days without feeding.
- Nits either hatch or die within a week and cannot hatch if they are away from the scalp.
- Lice cannot hop nor fly. They crawl.
- Pets do not transmit human lice.
- OTC treatments have lost their efficacy. Prescription products should be used.
- See also pediculosis corporis and pubis.
Small, white eggs (nits) are seen attached to the hair. With careful inspection, one may see the louse hiding amongst the hair near the scalp. Typically, there is much itching and inflammation of the skin. Cervical lymphadenopathy may occur.
All contacts should be assessed for infestation. Treatment should be contemporaneous so as not to spread disease back and forth.
Machine wash and dry all clothing and bedding worn in the two days before treatment. If unable to wash something, place the item in a plastic bag for two week. Vacuum floors and furniture around where the infested person sits or sleeps. Combs and brushes should be soaked in hot water for 10 minutes. A fine toothed (nit) comb may be used to remove dead lice and nits.
OTC treatments for head lice (permethrin 1%, pyrethrins with piperonyl butoxide) have lost their effectiveness and in some studies are no better than placebo. Prescription products should be used.
- Malathion 0.5% lotion (Ovide: applied uncovered for 8–12 hours and washed off) is approved as a single application for children 6 years and older. It is pregnancy category B.
- Oral ivermectin (250 µg/kg, repeat in 2 weeks),
- Topical ivermectin (Sklice: coat the scalp and hair, leave on for 10 minutes, then rinse off) is approved as a single application for patients 6 months and older. It is pregnancy category C
- Benzyl alcohol lotion, 5% (Ulesfia lotion) is approved for patients 6 months to 60 years of age. It is applied to initially and repeated on the 9th day. Not ovicidal so that is why you have to repeat.
- Spinosad 0.9% topical suspension (Natroba) is approved as a single application (is ovicidal) for patients 6 months and older. It is pregnancy category B.
AirAllé Lice Treatment is an FDA-cleared device which uses heated air (different from a blow dryer) to treat head lice. One treatment is needed (one hour of nit-picking and an hour of device usage) and it is approved for patients ages 4 and older.
Microscopic examination of hair showing hair nit (egg). Nits are laid by the adult female and are cemented at the base of the hair shaft near the scalp. Nits take about 1 week to hatch (range 6 to 9 days). Viable eggs are usually located within 6 mm of the scalp. This one is empty--already hatched.
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