Head Lice

What does head lice look like?

Since adult lice are the size of a sesame seed (2-3mm), head lice can be seen by the human eye. They live in human hair, draw blood from the skin, and lay eggs (called nits) on the hair shaft. Live nits are found less than 1/2 inch from the scalp and most often on hair at the back of the head in the neck region. Some children with lice complain of itchiness but many have no symptoms.

Is your child at risk?

Yes. Head lice will spread as long as children play together. They spread almost completely through human hair-to-hair contact, and pets do not spread lice. Anyone can get head lice. Children in child care, preschools, elementary or middle schools are at risk. Head lice is NOT a sign of being dirty. Head lice is not dangerous and DOES NOT spread diseases.

Do head lice spread in swimming pools?

Data show that head lice can survive under water for several hours but are unlikely to be spread by the water in a swimming pool.  Head lice have been seen to hold tightly to human hair and not let go under water.  Chlorine levels found in pool water do not kill head lice. 

Head lice may be spread by sharing towels or other items that have been in contact with an infested person's hair, although such spread is uncommon.  Children should be taught not to share towels, hair brushes, and similar items either at poolside or in the changing room. 

Swimming or washing the hair within 1-2 days after treatment with some head lice medicines might make some treatments less effective. Talk to your health care provider if you have questions. 

What can you do?

Parents are the key to looking for and treating head lice! The Iowa Department of Public Health advises parents to spend 15 minutes each week on each child carefully looking for head lice or nits. Persons with nits within ¼ inch of the scalp OR live lice should be treated. Careful use of a nit comb can potentially remove all lice. Each child should have his or her own comb or brush. Teach your child NOT to share hats, scarves, brushes, combs, and hair fasteners.

Treatment Calendar

The treatment days are scheduled to interrupt the lifecycle of the insect.  A nit comb should be used to comb the hair and can be bought at most pharmacies

Day 1

Medicated Shampoo

Day 8

Shampoo, condition and COMB

Day 2

COMB only


Day 9

Shampoo, condition and COMB

Day 3

Shampoo, condition and COMB

Day 10

Medicated Shampoo

Day 4

Shampoo, condition and COMB

Day 11

COMB only


Day 5

Shampoo, condition and COMB

Day 12

Shampoo, condition and COMB

Day 6

Shampoo, condition and COMB

Day 13

Shampoo, condition and COMB

Day 7

Shampoo, condition and COMB

Day 14

Shampoo, condition and COMB

Possible reasons treatment may not work

  1. Wrong diagnosis – dandruff, hair products, dust, and other objects can seem like nits (the white eggs) and other insects can look like lice
  2. Poor treatment – directions on the treatment product were not correctly followed
  3. Resistance to treatment – some lice are not killed by the chemicals in the over-the-counter treatments (permethrin and pyrethrin)
  4. Timing – the lice may take a few days to die; nits alone do not mean the child still has lice, look for crawling lice
  5. New lice – child got head lice again from playmate or family member

After the 14 day treatment, if crawling lice are still present, contact your healthcare provider who may recommend a prescription treatment for lice.

School exclusion

There is no need for children to be sent home or to miss school, though treatment should be started before returning to school the next day. 

School officials should ask parents to check their children’s hair at least weekly.

Head lice brochure

Order the free "Getting Rid of Head Lice" brochures

View the brochure / Spanish version

Additional resources

Head Lice (CDC)

IDPH head lice fact sheets