Watch Out for Back to School Illnesses: Head Lice


While classrooms are intended for learning and educational growth, they can be perfect breeding grounds for organisms that can cause illnesses in children, including head lice.

Every year, parents receive “the letter.” You know the one... saying that a student in your child’s school has been identified as having head lice. Thanks to Kathy Trail, BS, RN, CIC, Infection Preventionist at Sts. Mary & Elizabeth Hospital, you'll know exactly what to do if that letter comes to you.

What are head lice? The head louse is a parasitic insect that can be found on the head, eyebrows, and eyelashes. Head lice feed on human blood several times a day and live close to the human scalp. Head lice are not known to spread disease.

Who is at risk? In the U.S., infestation with head lice is most common among pre-school children attending child care, elementary school children, and the household members of infested children. It is estimated that between 6 and 12 million infestations occur each year among children ages 3 to 11.

How are lice spread? Anyone who comes in head-to-head contact with someone who already has head lice is at greatest risk. It is uncommon for lice to spread by contact with clothing or other personal items used by an infested person. Personal hygiene or cleanliness in the home or school has nothing to do with getting head lice.

What do head lice look like? Head lice have three forms: 

1. Egg (also called a nit):  Nits are lice eggs that are laid at the base of the hair shaft nearest the scalp. Nits are firmly attached to the hair shaft and are oval-shaped and very small and hard to see.  Nits often appear yellow or white and may be confused with dandruff. 

2. Nymph:  A nymph is an immature louse. A nymph looks like an adult head louse, but it is smaller. 

3. Adult:  The fully grown and developed adult louse is about the size of a sesame see, has 6 legs, and is tan to grayish-white in color.  Adult head lice may look darker in persons with dark hair.  Adult female head lice are usually larger than males and can lay about 6 eggs each day.

What are the signs and symptoms of head lice infestation?

  • Tickling feeling of something moving in the hair
  • Itching, caused by an allergic reaction to the bites
  • Irritability and difficulty sleeping; head lice are most active in the dark
  • Sores on the head caused by scratching, which can become infected with bacteria found on the person’s skin

How is head lice infestation treated?
Treatment requires using an over the counter (OTC) or prescription medication. Apply lice medicine, also called pediculicide, according to the instructions contained in the box or printed on the label.

The CDC has additional information and more specific treatment instructions.