PDF of the Head Lice Fact Sheet

What is Head Lice?

This page was reviewed or revised on Thursday, August 13, 2009.

What to Look For

These insects are only 1-2 mm long, flat, greyish-brown, have no wings, and are hard to see. They are most commonly found on the scalp, behind the ears and near the neckline at the back of the neck. They live and breed on the hair of the head. If the louse falls off a person, it dies within 2 days.  Adult female lice produce many nits (eggs). 

Nits are half the size of a pinhead, and oval in shape. They may look like dandruff but they’re firmly glued to the hair and can’t be flicked off. New eggs, which are laid right next to the scalp, are tan to brown in colour and difficult to see. Nits more than 1 cm from the scalp have likely hatched or died. Itching and scratching are common signs of head lice. Sometimes there are no symptoms at all.

How to Get Rid of Head Lice

Treating head lice requires two treatments, one week apart.

Get a head lice product from your drug store. If your child has extra long hair you may need to use a second bottle. Ask your pharmacist if you have any questions. Head lice products do not prevent head lice. They are used to treat an infestation. 

Consult your doctor before choosing a product when

• treating children under two years of age

• pregnant or breastfeeding

• lice are discovered on eyebrows, eyelashes or facial hair

• skin of the scalp is broken or infected

When choosing a product, read the list of contents and directions carefully. The most effective head lice products are: 

Pyrethrins (e.g. R&C shampoo) should not be used for anyone with a known allergy to ragweed or chrysanthemums.

Permethrin (e.g. NIX) should not be used for persons with a known allergy to chrysanthemums, synthetic pyrethroids, or pyrethrins. Do not use on children under two years of age unless directed by a physician.

Lindane (e.g. Kwellada) should not be used for children under two years of age unless directed by a physician. For children age two to five , Lindane is recommended only on the advice of a nurse, pharmacist or physician.

Do not use conditioner or combination shampoo/conditioner before using lice medication. Do not re-wash hair for 1-2 days after treatment. Itching may increase for a short while after treatment but this is not a concern.

When using a head lice product:

Have the infested person put on clean clothing after treatment.  

Sometimes head lice resist one product. If head lice medication does not kill any crawling bugs within 24 hours, and the product was used correctly, then resistance is likely. Try another product followed by the second treatment.  

Rinsing a child’s hair under a tap (instead of a shower) will limit skin exposure and prevent the child from swallowing some product. These products should not be used near the eyes, nose or mouth. A towel held tightly over the eyes protects them during treatment.  

When treating another person, wear plastic or rubber gloves to avoid unnecessary exposure to the product.  

Store unused head lice products away from the reach of young children.  

After treatment, check hair and comb with a nit comb to remove nits and lice every 2-3 days. 

Removing the nits

Bright, natural light helps you to see the nits better.  First, comb the hair. Then take hold of a lock of hair and use your thumbnail against your first finger to strip the nits from the hair. Start from the roots and move down to the tips. Place the nits in a bag. Pin back that lock of hair and continue until all nits are removed. Try to remove the very tiny eggs laid right next to the scalp.  

You can also comb out the nits holding a fine tooth comb on a downward angle. This is easier if a conditioner is used after treatment (avoid conditioner after use of NIX).

Second treatment:

Apply a second treatment in one week to kill any newly-hatched lice before they can lay eggs. After the second treatment and removal of the nits, check the head twice a week for four weeks to make sure all lice and nits are gone.

Close Contacts

Follow up of close contacts is very important. Check the heads of all family members and notify others such as grandparents, baby sitters, and playmates parents. All affected persons should be treated at the same time.  Tell the school, daycare centre, etc., so parents can be informed to check their children’s heads to prevent further spread.

Cleaning Personal Items

Vacuuming areas where an affected person usually sits or lays (e.g. sofa, carpet) is recommended. Wash with soap and hot water all combs, brushes, hats, pillow cases, sheets, clothes and towels that have been worn or used by the person affected, two days before treatment is started. Combs, brushes, etc. can also be soaked in rubbing alcohol for an hour. The heat of the water or the hot cycle of your clothes dryer will kill any live lice and nits.  Items that cannot be washed (e.g. stuffed animals) can be sealed in a plastic bag for a couple of weeks which will assure any lice or nits are killed.

Points to Remember:

• A person left untreated among close contacts is a common reason for reoccurrence.
• Head lice do not live on dogs, cats or other animals. 
• Discourage children from sharing hats, combs, hair accessories, helmets, etc.
• Keeping hair short will not prevent head lice. 
• Check young school-aged children regularly for head lice. More often if there is an outbreak.
• Don’t use extra amounts of lice medication unless instructed. These drugs can be dangerous when misused or overused.
• Don’t mix head lice medications.
• Don’t treat more than three times with the same medication if it does not seem to work. See your health care provider for an alternative medication.