What are head lice?
Head lice are parasitic insects that live in the hair and scalp of humans. The scientific name for head louse is Pediculus humanus capitis. Another name for infestation with head lice is pediculosis.

Head lice develop in three forms: nits, nymphs, and adults.

Nits: Nits are head lice eggs. They are hard to see and are often mistaken for dandruff or droplets of hairspray. Nits are found firmly attached to the hair shaft. They are oval and usually yellow to white. Nits take about 1 week to hatch.

Nymphs: Nits hatch into nymphs. Nymphs are immature adult head lice. Nymphs mature into adults about 7 days after hatching. To live, nymphs must feed on blood.

Adults: An adult louse is about the size of a sesame seed, has six legs, and is tan to greyish- white. In persons with dark hair, adult lice will look darker. Adult lice can live up to 30 days on a person's head. To live, adult lice need to feed on blood. If a louse falls off a person, it dies within 2 days.

How are head lice spread?

Head lice are spread easily from person to person by direct contact. People can get head lice by:

Coming into close contact with an already infested person. In children, contact is common during play, while riding the school bus, and during classroom activities in which children sit in groups close to each other.

Wearing infested clothing, such as hats, scarves, coats, sports uniforms, or hair ribbons
Using infested combs, brushes, or towels
Lying on a bed, couch, pillow, carpet, or stuffed animal that has been contaminated
Lice do not jump or fly. Lice are not spread to humans from pets or other animals.

What is the treatment for head lice infestation?

Getting rid of head lice requires treating the individual, the family, and the household.

Treat the individual and the family -- This requires using an over-the-counter or prescription lice- killing medicine. Treat only persons who are infested. Remember that all lice-killing products are pesticides. Follow these treatment steps:

• Remove all clothing.
   

• Apply lice-killing medicine, also called pediculicide [peh-DICK-you-luh-side], according to label instructions. If the affected person has extra-long hair, you may need to use a second bottle.
   

• WARNING: Do not use a creme rinse or combination shampoo/conditioner before using lice-killing medicine. Do not re-wash hair for 1-2 days after treatment.
   

• Have the affected person put on clean clothing after treatment.
   

• If some live lice are still found but are moving more slowly than before treatment, do not re-treat. Comb dead and remaining live lice out of the hair. The medicine sometimes takes longer than the time recommended on the package to kill the lice.
   

• After treatment, if no dead lice are found and lice seem as active as before, the medicine may not be working. See your health-care provider for a different medicine. Follow treatment instructions.
   

• Remove nits and lice from the hair shaft using a nit comb, often found in lice-killing medicine packages. Flea combs used for cats and dogs can also be used.
   

• After treatment, check, comb, and remove nits and lice from the hair every 2-3 days.
   

• Re-treat in 7-10 days.
   

• Check all treated persons for 2-3 weeks until you are sure all lice and nits are gone.
  
  
  
  
  
  
   

Temporary Prevention