Head lice

What are head lice?

Lice are small, grey, flat, wingless insects that live on the surface of the scalp. An adult louse is 2 mm to 4 mm long.

Lice suck blood from the scalp. They survive by staying close to the scalp for food and shelter. Adult lice lay eggs (nits) that stick to the hair shaft.

A head lice infestation is also called pediculosis. It does not indicate poor hygiene. In fact, head lice prefer clean hair and skin.

Signs and symptoms of head lice

Common symptoms of head lice include:

  • itchiness of the scalp
  • tiny red bumps on the scalp
  • presence of lice, although they are hard to see
  • light grey lice eggs (nits) sticking to the hair shaft.

Sometimes there are no symptoms at all for the first few weeks.

How to check if your child has head lice

If you suspect your child has head lice, use the following steps to check their hair.

  1. Wet your child’s hair.
  2. Comb it with a lice-removal comb (a small fine-toothed comb that you can buy in your local pharmacy).
  3. Submerge the comb in water in a white bowl.
  4. Look for the adult or baby lice at the bottom of the bowl.

You may see the nits floating in the water, but they may be so well ‘stuck’ that you may also need to examine the hairs near your child’s scalp.

It is also possible to see small live lice in your child’s hair. Check especially around their ears and neckline.

Causes of head lice

Lice infestation is very common. Children and adults can catch lice easily through direct contact with another person who has lice or by sharing hats, combs, headphones, towels or bedding. Lice can move from one head to another if two people literally "put their heads together", but they cannot jump any significant distance.

How to treat head lice

Consult a doctor before treatment if your child is under two years old or has allergies. Otherwise, you can treat your child at home. There are several treatment options.

One common option is to use approved, medicated lice-killing shampoos or lotions and special combs. These are available at your local pharmacy without a prescription. Each product is applied differently, so read the directions carefully. Make sure to rinse the lotion from your child’s skin to avoid irritation.

Most products are not 100 percent effective the first time you use them; you will usually need to repeat the treatment about a week later.

Various other treatments are available, but some work better than others. Ask your pharmacist for advice on the best option for your child.

How to prevent the spread of head lice

Check and treat

  • Check all family members for head lice. Each person who has head lice needs to be treated as soon as possible.

Wash combs, brushes, bedding and towels

  • If head lice are found, wash all combs and brushes in boiling water for 10 minutes to kill any lice or eggs.
  • Wash all bedding and towels in hot water and dry them in a tumble dryer on a high setting for 45 minutes.
  • Put anything that cannot be washed in sealed, air-tight bags for two weeks.

Tell your child’s school

  • Contact your child’s school if your child has head lice so the school can inform other parents.

Keep personal items separate

  • Encourage your child not to share hats, combs, brushes, headphones or bedding with other children at school or at home.

Key points

  • Head lice infestations are common in school children. They are not a sign of poor hygiene.
  • Symptoms include itchiness and red bumps on the scalp. Some children do not show symptoms for weeks.
  • The best way to detect head lice is to use a fine-toothed comb on wet hair.
  • To treat head lice, apply an approved head lice lotion or shampoo. You may need to re-apply it about a week later.
  • Tell your child’s school immediately if you discover head lice.
  • Discourage your child from sharing hats, combs or headphones.
Elizabeth Berger​, BA, MD, FRCPC, FAAP, MHPE​​