From the Guidelines
The recommended treatment for lice infestation involves using over-the-counter pediculicides like permethrin 1% (Nix) or pyrethrin with piperonyl butoxide (RID, A-200). Apply the medication according to package instructions, typically leaving it on for 10 minutes before rinsing. A second treatment is usually needed 7-10 days later to kill newly hatched lice. For resistant cases, prescription medications such as malathion 0.5% (Ovide) may be necessary, as it has high ovicidal activity and a single application is adequate for most patients 1.
In addition to medication, use a fine-toothed lice comb to remove lice and nits daily for at least two weeks. Wash all bedding, clothing, and personal items used in the past 48 hours in hot water (at least 130°F) and dry on high heat. Items that cannot be washed should be sealed in plastic bags for two weeks.
- Family members and close contacts should be examined and treated if infested, as they are at increased risk of infestation 1.
- All socioeconomic groups are affected, and head lice infestations are common in many parts of the world, with a prevalence of 13% in schoolchildren in Australia and 43% in a slum in Brazil 1.
- It is essential to note that head lice infestation is not significantly influenced by hair length or by frequent brushing or shampooing, but daily brushing can help reduce the number of live lice 1.
These treatments work by either paralyzing the lice's nervous system or suffocating them, preventing them from reproducing and spreading further. Malathion 0.5% (Ovide) is a highly effective treatment option, but it is contraindicated in children younger than 24 months and has a high alcohol content, making it highly flammable 1.
From the FDA Drug Label
Apply malathion lotion on DRY hair in amount just sufficient to thoroughly wet the hair and scalp. Pay particular attention to the back of the head and neck while applying malathion lotion. Wash hands after applying to scalp. Allow hair to dry naturally - use no electric heat source, and allow hair to remain uncovered. After 8 to 12 hours, the hair should be shampooed. Rinse and use a fine - toothed (nit) comb to remove dead lice and eggs. If lice are still present after 7 - 9 days, repeat with a second application of malathion lotion. Further treatment is generally not necessary. Other family members should be evaluated by a physician to determine if infested, and if so, receive treatment. The recommended treatment for lice infestation is to apply malathion lotion to dry hair, thoroughly wetting the hair and scalp, and paying particular attention to the back of the head and neck. After 8 to 12 hours, shampoo the hair and use a fine-toothed comb to remove dead lice and eggs. If lice are still present after 7-9 days, a second application of malathion lotion may be necessary 2. Key steps include:
- Applying malathion lotion to dry hair
- Allowing hair to dry naturally
- Shampooing hair after 8-12 hours
- Using a fine-toothed comb to remove dead lice and eggs
- Repeating treatment if necessary 2
From the Research
Lice Treatment Options
- Numerous therapies are available for the treatment of head lice infestation, including over-the-counter and prescription formulations 3
- Treatment recommendations include the use of pyrethrin or permethrin, with malathion as a second-line therapy due to its flammability 3
- Orally administered ivermectin has been reported to be efficacious, but it is not currently a US Food and Drug Administration-approved pediculicide 3
Efficacy of Different Treatments
- A study comparing oral ivermectin with 0.5% malathion lotion found that ivermectin had superior efficacy in treating difficult-to-treat head lice infestation 4
- Another study found that oral ivermectin was a promising effective approach for the treatment of head lice, with a cure rate of 92.5% after a second dose for nonresponders 5
- A case report found that pubic lice resistant to pyrethrins were effectively treated with 5% permethrin 6
Treatment Guidelines
- Effective therapeutic protocols for the treatment of pubic lice include application of approved insecticidal products to all body and scalp hair, retreatment at seven days, and use of mechanical removal of lice and eggs 6
- Treatment modalities for head lice infestation include over-the-counter permethrin and pyrethrin, and prescription medicines, including malathion, lindane, benzyl alcohol, and spinosad 7
- Alternative medicine and physical treatment modalities are also available, and the problem of resistance to treatment should be taken into consideration 7