Head Lice Patient Information Fact Sheet

What are head lice?
Head lice are tiny, wingless insects that remain smaller than a match head when fully grown. They are grey/brown in color and very difficult to see, particularly in dry hair. Head lice infestation is more common in children than in adults. Infestation with head lice is also known as pediculosis.

The presence of head lice does not indicate a lack of good hygiene. They will infest any type of hair but tend to be more common in people with long hair. Head lice survive by biting the scalp and sucking blood though it. At any time, an infested person will have less than a dozen live lice on their head, although there may be hundreds of unhatched or empty egg sacs in the hair close to the scalp. These empty egg sacs are white and shiny and are known as “nits.”

Although unwanted, head lice cause minor problems and do not carry disease. They are an irritation and treatment is needed to remove them. Treatment is usually referred to as “delousing.” Treatment should not be started until the presence of at least one live, moving louse has been confirmed because the misuse of some toxic substances may cause more harm than the head lice themselves.

What causes a head lice infestation?
Head lice are unable to fly or jump and prefer to live on the scalp. Head lice are spread by direct head-to-head contact with a person who is infested. Head lice can affect people of any age but are more common in children because of the increased likelihood of direct contact. They die within a day of being removed from their human host and so are not found on furniture or household objects. There is no need to wash or fumigate clothing that has come into contact with head lice. Pets (eg, dogs and cats) do not carry head lice and do not need to be treated.

What are the symptoms of a head lice infestation?
Head lice infestation can cause the scalp to itch in some people but not in others. Itching is caused by sensitivity to lice saliva. The only other real “symptom” is finding a live louse in the hair. It is advisable to check children’s hair regularly, particularly if an outbreak of head lice has been reported at their school or if they have been in contact with someone with head lice.