Delousing

The treatment of human head lice infestation is a process for removing head lice parasites from human hair and it has been debated and studied for centuries. However, the number of cases of human louse infestations (or pediculosis) has increased worldwide since the mid-1960s, reaching hundreds of millions annually. There is no product or method which assures 100% destruction of the eggs and hatched lice after a single treatment. However, there are a number of treatment modalities that can be employed with varying degrees of success. These methods include chemical treatments, natural products, combs, shaving, hot air, and silicone-based lotions.

The American Academy of Pediatrics states treatment for head lice should never be initiated unless there is a clear diagnosis for head lice since all treatments have potential side effects.

Lice eggs hatch 6–9 days after oviposition. Therefore, a common recommendation is to repeat treatment with a pediculicide at least once after 10 days, when all lice have hatched. Between the two treatments (Days 2–9) the person will still be infested with lice that hatch from eggs not killed by the anti-louse product. Between the treatments, it is advised to wet the hair and comb daily with a louse-comb to remove the hatching lice.

If no living lice are found, the treatment was successful, even if nits/eggs are visible on the hair. If living lice are still present, repeat the treatment using an anti-louse product with a different active ingredient. Prophylactic treatment with pediculicides is not recommended. Itching may persist for up to a week after head lice eradication.

Devices blowing heated air onto the scalp have been tested for efficacy in killing lice and eggs and shows up to 99% mortality of eggs and 88% mortality of hatched lice. The louse loses body moisture to the heated air and within the treatment period becomes desiccated and dies. Currently, there is only one FDA approved medical device that offers this technology.

A standard home blow dryer will kill 96.7% of eggs with proper technique. To be effective, the blow dryer must be used repeatedly (every 1 to 7 days since eggs hatch in 7 to 10 days) until the natural life cycle of the lice is over (about 4 weeks).

...
Wikipedia