American Academy of Pediatrics guidelines for the prevention and treatment of head lice infestation.

The American Academy of Pediatrics (AAP) established diagnosis and treatment guidelines for pediculosis in 2002. Ideally, diagnosis should be based on the observation of a live louse. The presence of nits is also used by many people to positively diagnose an infestation, although a nit located farther from the scalp than 1 cm is unlikely to be viable. Other material on the scalp may be mistaken for nits, leading to misdiagnosis. Because lice are not associated with serious medical problems, the primary consideration of the AAP regarding treatment is the safety of pediculicides and other products used to treat head lice. From a pediatrician's perspective, no significant risk is acceptable. Over-the-counter (OTC) pyrethroid products (pyrethrin and permethrin) are commonly used by parents to treat their children and are generally considered safe for most people. Pyrethroids are not completely ovicidal, however, so a second application is required. Misuse and overuse of these products have contributed to the development of resistance. Prescription products include permethrin 5%, lindane, and malathion 0.5%. Resistance to permethrin 5% and lindane has been documented. In addition, lindane is associated with serious adverse events and should be used with caution only in a select population. Malathion 0.5% is about 98% ovicidal, and no resistance has been reported. Malathion is highly effective, but AAP guidelines note that the product is flammable and serious adverse effects can occur with ingestion. Very few cases of ingestion have occurred, and no reported cases of flammability, but children being treated with malathion should be carefully supervised, and this pediculicide should not be used unless treatment with OTC products has failed. AAP guidelines also state that no-nit policies in schools are detrimental, causing lost time in the classroom, inappropriate allocation of the school nurse's time for lice screening, and a response to infestations that is out of proportion to their medical significance. Accurate diagnosis, safe treatment options, and a common-sense approach to managing infestations in schools are recommended.