What is the treatment for pediculosis (lice infestation)?

From the Guidelines

To treat lice, use over-the-counter pediculicides containing permethrin 1% (like Nix) or pyrethrin with piperonyl butoxide (like RID), as recommended by the most recent and highest quality study 1. The treatment should be applied to dry hair, left on for 10 minutes, and then rinsed off. It is essential to repeat the treatment after 7-10 days to kill newly hatched lice, as the initial treatment may not kill all eggs. For resistant cases, prescription medications like spinosad (Natroba), ivermectin (Sklice), or malathion (Ovide) may be necessary, as suggested by 1. Combining medication with thorough combing using a fine-toothed nit comb to remove lice and eggs is also crucial. Additionally, washing all bedding, clothing, and personal items in hot water (130°F) and drying on high heat, sealing non-washable items in plastic bags for two weeks, and vacuuming furniture and floors where infected persons sat or lay can help prevent reinfestation, as noted in 1 and 1. Lice treatments work by attacking the nervous system of the parasites while sparing humans due to the different physiological sensitivities. The two-treatment approach is crucial because medications kill live lice but may not kill all eggs, which can hatch within 7-10 days, potentially causing reinfestation if not addressed with the second treatment. Key considerations in choosing a treatment include effectiveness, safety, local patterns of resistance, ease of use, and cost, as emphasized by 1. It is also important to note that improper application of the pediculicide should be considered first as a cause of treatment failure, as mentioned in 1. Overall, the goal of treatment is to eliminate the lice infestation while minimizing the risk of adverse effects and promoting the best possible outcome in terms of morbidity, mortality, and quality of life.

From the FDA Drug Label

Directions Important: Read warnings before use Adults and children 2 years and over Inspect check each household member with a magnifying glass in bright light for lice/nits (eggs) look for tiny nits near scalp, beginning at back of neck and behind ears examine small sections of hair at a time unlike dandruff which moves when touched, nits stick to the hair if either lice or nits are found, treat with this product Treat apply thoroughly to DRY HAIR or other affected area. For head lice, first apply behind ears and to back of neck. allow product to remain for 10 minutes, but no longer use warm water to form a lather, shampoo, then thoroughly rinse for head lice, towel dry hair and comb out tangles Remove lice and their eggs (nits) se a fine-tooth or special lice/nit comb Remove any remaining nits by hand (using a throw-away glove). after combing, thoroughly recheck for lice/nits. Repeat combing if necessary check daily for any lice/nits that you missed a second treatment must be done in 7 to 10 days to kill any newly hatched lice if infestation continues, see a doctor for other treatments

The treatment for lice involves:

• Inspecting each household member for lice/nits
• Applying the product to dry hair or affected area
• Rinsing and towel drying hair
• Combing out tangles and removing lice and nits using a fine-tooth or special lice/nit comb
• Rechecking for lice/nits and repeating combing if necessary
• A second treatment must be done in 7 to 10 days to kill any newly hatched lice 2 2

From the Research

Lice Treatment Options

• Topical pediculicides and oral medications are available for the treatment of head lice, and when used in combination with environmental decontamination, these drugs can be very effective in eradicating head lice infestation without significant adverse events 3
• Over-the-counter and prescription treatments, including pyrethroids and permethrin, lindane, malathion, ivermectin, and trimethoprim-sulfamethoxazole, can be used to treat head lice 3
• Spinosad is a new pediculicide that has been introduced and has shown efficacy in treating head lice, with 82.5% and 86.1% of patients free of live lice 14 days after treatment 4
• Permethrin 1% is still the first-line treatment of head lice, but resistance is a growing concern, and alternative topical pediculicidal agents such as malathion and benzyl alcohol are available 4

Treatment Efficacy and Safety

• The efficacy of spinosad in treating head lice has been demonstrated in several trials, with 84.6% and 86.7% of patients free of live lice 14 days after treatment 4
• The most common reported adverse events with spinosad were eye and scalp irritation, but they were not statistically significant 4
• Malathion 0.5% is about 98% ovicidal, and no resistance has been reported, but it is flammable and can cause serious adverse effects with ingestion 5
• Dimeticone, a silicone compound, has few known adverse effects and has been shown to be effective in eradicating head lice in 70% to 97% of patients after two weeks 6

Treatment Guidelines and Recommendations

• The American Academy of Pediatrics (AAP) recommends that diagnosis of head lice should be based on the observation of a live louse, and that treatment should be safe and effective 5
• The AAP also recommends that no-nit policies in schools are detrimental and that accurate diagnosis, safe treatment options, and a common-sense approach to managing infestations in schools are recommended 5
• Pyrethroids are no longer the first-choice treatment for head lice due to resistance and potential toxicity, and dimeticone is a better choice due to its few known adverse effects and proven efficacy 6