Treatment of human head lice

Mother hunting for headlice

The treatment of human head lice is a process that 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.

General recommendations

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

Read the instructions carefully before using any anti-louse product. During the treatment, it is particularly important to note the starting time and to treat the hair for the exact period specified in the instructions.

Because eggs hatch 6–9 days after oviposition, treatment with a pediculicide is recommended to be repeated 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. Therefore, with some products, a third treatment on Day 5 is recommended. Between the treatments, it is advised to wet the hair and comb daily with a louse-comb to remove the hatching lice.

Hold a towel over the face to prevent contact of the product with the eyes of the infested person; and, if the product does come in contact with the eyes, rinse well with water. While the hair is still wet, use a louse comb 3–4 minutes, to remove lice and eggs.

One to three days after the last treatment (Days 11-13), hair should be checked with a louse comb. 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.

However, head lice are known to be resistant to commercial products.^{[citation needed]}

A heated air device designed to desiccate and thus to kill headlice

Heated air

Devices blowing heated air onto the scalp have been tested for their efficacy to kill lice and eggs and can show up to 98% mortality of eggs and 80% mortality of hatched eggs. Currently there is only one FDA Cleared medical device that offers this technology.

Combing

Combs

For a treatment with louse comb alone, it is recommended to comb the hair for an hour to an hour and a half (depending the length and type of the hair) daily or every second day for 14 days. Wetting the hair especially with water and shampoo or conditioner will facilitate the combing and the removal of lice, eggs and nits.

A special finetooth comb that can pick out lice is used. The space between the teeth of the comb should be no more than 0.3 millimetres (0.012 in). Plastic combs are effective for very short-term use, but the spacing between the teeth will quickly spread out after repeated usage. Metal combs, being less flexible, are more effective for multiple uses.

Following are instructions for wet combing:

• First, comb through wet hair with an ordinary comb to relieve knots and tangles.
• Apply hair conditioner to make it easier to comb the hair with the fine-toothed comb.
• Comb through every bit of hair, pulling the comb from the scalp to the hair ends. After every comb-through, examine and rinse the comb. Use an old toothbrush to remove eggs and nits from the comb and flush the eggs down the sink. Comb through the entire head and scalp at least twice. Afterwards, rinse the conditioner out.
• Repeat the aforementioned steps every day or every second day to catch any new lice that have hatched since the previous combing.
• Repeat the aforementioned procedure until lice are not found for at least two treatments in a row. The Pharmaceutical Society of Australia recommends treating with comb and conditioner every two days until lice are not found for ten consecutive days.

Electronic combs

Electronic lice combs use a small electrical charge to kill lice. The metal teeth of the comb have alternating positive and negative charged tines, which are powered by a small battery. When the comb is used on dry hair, lice make contact with multiple tines of the fine-toothed comb, thereby closing the circuit and receiving an electrical charge.

Electronic lice combs have been tested and found to be safe and effective way to kill head lice, and as this is a non-chemical treatment, resistance does not seem to be a consideration because the mechanism of action is fundamentally electrocution.

Substances/pediculicides

Main article: pediculicide

Today, insecticides used for the treatment of head lice include organochlorines (lindane), organophosphates (malathion), carbamates (carbaryl), pyrethrins (pyrethrum), pyrethroids (permethrin, phenothrin, bio-allethrin), and spinosad (spinosyn A and spinosyn D).

The only agents approved by the FDA for treatment of pediculosis are lindane and malathion.

Use of natural substances has also been described.

Procedures

Shaving the head

Shaving the head or cutting the hair extremely short can be used to control lice infestation. Short hair, baldness, or a shaven scalp are generally seen as a preventive measure against lice infestation. However, it is not recommended that children be suddenly shaved if there is reason to believe that they may experience adverse psychological effects.

Infestation with lice is not a disease and the medical symptoms are normally minimal. In any case, health providers and parents should try not to create emotional problems for children during examination and treatment. Shaving of the area above and behind the ears and the upper part of the neck while leaving the crown of the head with hair is commonly used to prevent lice among tribes in Africa, Asia, and America (in America - Mohawk style).

External links

• Centers for Disease Control and Prevention: Division of Parasitic Diseases
• James Cook University, Australia: Head Lice Information Sheet
• MedicineNet.com: Head Lice Infestation (Pediculosis)
• Phthiraptera Central: Bibliography of Lice
• University of Nebraska: Head Lice Resources You Can Trust
• National Pediculosis Association