Head lice (Pediculus Humanus Capitus) are extremely common, especially in school children. Approximately 7% of a community will have head lice at any one time, with 6-12 year olds being the most common sufferers¹. Like threadworms, infestations tend to happen more during school term time, but can occur at any time of the year.

What are head lice?
Head lice are only found on the scalp and eyebrows of humans. Transmission is via head-to-head contact and is not related to personal hygiene.

Head lice appear in three different forms:

• Nits are head lice eggs. The oval, yellowy-white eggs are hard to see and may be confused with dandruff. They attach themselves to the hair shaft and take about a week to hatch. The eggs remain after hatching and many nits are actually empty egg cases.
  
• Nymphs hatch from the nits. The baby lice look like the adults, but are smaller. They take about 10 days to mature to adults and feed on blood to survive.
  
• Adults (or lice) are about the size of a sesame seed. They have six legs and are tan to greyish-white. The legs have hook-like claws which hold onto the hair. Adults can live up to 30 days and feed on blood.

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Head lice move from head to head via direct contact. They cannot fly, jump or swim. Once on the head, the mature females mate and lay eggs. Females generally outnumber males, which maximises egg production. Each female lays about eight eggs a night and mates again before laying the next batch. The eggs are glued to the base of hair strands, next to the scalp, and take 7-10 days to hatch. Live eggs are plump, scalp coloured, about the size of a pinhead and are always found within 1 cm of the scalp. Darker eggs that are found further from the scalp are dead.

Once hatched, the young louse will become a mature adult within 10 days. The empty egg case turns a brilliant white, and this is normally the first sign of a head lice infestation.

Lifecycle

"Head lice jump from one head to another"

"Head lice drown in water"

"Head lice only live in dirty hair"

	Intense itchiness on the scalp
	Red patches on the scalp (caused by scratching)
	Nits and/or eggs visible (they are oval shaped and look like white dandruff-like spots attached to the hair)
	Lice visible
	Black specks on the bedding and/or clothes

Only a third of children with head lice have an itchy head. Sometimes there are no symptoms at all, which is why it is important to carry out regular checks.

If you find any live lice on your child's head then do check every other member of the family, including any adults who have close contact with the child.

It's also helpful to tell the school and parents of any other child who may have had direct head-to-head contact with your child, so that other children can be checked for head lice if necessary.

A common method of finding head lice is by wet-combing:

1. Wash hair using an ordinary shampoo and apply conditioner
2. Use a wide-toothed comb to detangle the hair
3. Comb the hair when wet with a fine-toothed comb. This will hook out any lice
4. Pay special attention to the nape of the neck and behind the ears as head lice prefer these warm, sheltered areas
5. Rinse the hair

Regularly wet-combing your child’s hair is the best way of keeping head lice at bay. The sooner you detect them, the sooner you can get rid of them and prevent other family members from getting head lice.

Another recommended way to search for head lice and nits is to buy a specially designed detection comb or 'nit comb' from a pharmacy.
Children with thick hair often find that using conditioner on their wet hair makes it easier to get the nit comb through. If they have curly hair you may find that oiling rather than wetting makes it easier to use the nit comb effectively.

You can also part the hair and look for eggs and nits, but the lice will move quickly into hiding.

1. The Practitioner, February 1998, Vol 242, pg126-129