Head Lice Information

Lice are small insects, which may live on the head and hairy parts of the body. The type of louse which affects the head is particularly common and anyone can catch them. Lice spread by direct head-to-head contact with an infected person and therefore tend to be more common in children as their play activities facilitate this type of contact. Live lice are transmitted when the lice are alive on a person’s head. Lice cannot live away from a human host; most die within 3 days. Lice cannot jump, swim or fly. Their presence does not reflect standards of hygiene. The female lice lay eggs which glue to the hair and only become easily visible when they have hatched and are empty (nits). Nits remain in the hair until it falls out, which may take up to 2 years. Itching and scratching are usually the first signs of headlice but are due to anallergic reaction which can take four to eight weeks to develop after the initial infection. The presence of nits (empty egg casts) does not mean that active infection is present and is not an indication for treatment.

Treatment is only required if live lice are seen in the hair (not nits). There are a number of different treatment options. Research suggests that the use of chemical agents is more effective than other treatment options, such as lavender, tea-tree oil, and eucalyptus.

Treatments such as dimeticone, phenothrin, or malathion are recommended. Dimeticone (Hedrin R) is a nonneurotoxic agent. It is important to follow the treatment instructions carefully. Alternatively parents may wish to try mechanical removal of lice by wet combing with special narrow-toothed combs and conditioner (“bug busting”). Results of research on this method are mixed.

Results depend on a correct and consistent technique and time spent wet combing.


The best way to stop infection is for families to learn how to check for lice on a regular basis. This way they can find any lice before they have a chance to breed. They can then treat them and stop them spreading.

Regular combing of the hair with a fine-toothed comb (detection combing) should be encouraged at all times. It is better to do this on wet hair. Treatment is only required if live lice are seen in the hair (not nits). If live lice are detected on one member of the family it is important that all other family members are checked for headlice.

In school if live lice are seen on a pupil’s head the pupil’s parent(s) should be advised to inspect and treat their child for headlice. If there are several cases it may be of benefit to send a letter to all parents advising them to inspect their children’s heads and initiate treatment only if live lice are seen.

Exclusion is unnecessary.

From Chapter 9 Page 38 of Management of Infectious Disease in Schools September 2013 by Public Health Medicine Communicable Disease Group.