Lice

Diagnosis

Lice are diagnosed through a close inspection of the hair, scalp, skin or clothing. A magnifying lens and a fine-toothed comb may be used to detect live lice or their eggs. Diagnosis depends on the type of lice involved.

Head lice

Head lice are diagnosed when live lice are found on the scalp or in the hair. A nit comb is used to look for lice eggs, called nits, but finding nits alone does not confirm an active infestation.

Body lice

Body lice are diagnosed by finding eggs or crawling lice in the seams of clothing or bedding. They may also be seen on the skin when they come out to feed.

Pubic lice

Pubic lice are diagnosed when moving lice or eggs are seen on pubic hair or on coarse hair in other areas such as the chest, eyebrows or eyelashes.

Treatment

Several methods can kill head lice and their eggs. These include wet combing, smothering and dehydrating techniques, as well as medicines available with or without a prescription. Treatment often involves permethrin or pyrethrin applied to the affected areas.
Permethrin may be used for people 2 months and older, while pyrethrin is recommended for people 2 years and older. After using these treatments, nits should be removed with a nit comb. For the next 2 to 3 weeks, comb out the hair every 2 to 3 days. Repeat treatment on day nine or ten.

For body lice, bathing with soap and water and washing clothes and bedding in hot water may be enough. When medicine is needed, apply it to affected areas at bedtime, avoid the face, rinse in the morning and repeat on day nine.

What to do when treatments don’t work

Medicines may not work in some regions due to resistance or incorrect use. When over-the-counter treatments fail, other prescription options may be recommended.

• Spinosad is for adults and children 6 months and older. Apply to dry hair for 10 minutes, rinse over a sink and avoid shampooing for 24 to 48 hours. Repeat after seven days if lice remain.

• Malathion is for adults and children 6 years and older. Apply to dry hair for 8 to 12 hours, rinse over a sink and avoid shampooing for 24 to 48 hours. Repeat in seven days if needed. This medicine is flammable and must be kept away from heat or flames.

• Ivermectin may be taken by mouth for head or body lice when other treatments fail. It is suitable for children over 33 pounds, with a possible repeat dose in 7 to 10 days. It should not be used during pregnancy or breastfeeding. Ivermectin lotion is also available without a prescription, but repeat applications should be discussed with a healthcare professional.