Head Louse Facts and Information

A head louse (Pediculus Humanus Capitis) is an insect that loves to make its home in human hair and its feeding ground is the human scalp from which it draws blood - its sole food.

The head louse pierces the scalp with its retractable fang injecting saliva containg anaesthetic, anticoagulant and enzymes thus preventing the host from being aware of the bite.

Overtime, the substances contained in the saliva of the Head Louse can have a negative impact on the nervous system of the host - the generally accepted origin of the terms "feeling lousy" and “nit-wit”.

The secretions injected as the head louse feeds are also known to cause other secondary infections and exacerbating other conditions such as rhinitis, conjunctivitis, psoriasis and various skin and sleep disorders.

As the anaestheitic injected by the Head Louse wears off, the host may feel intense itching causing scratching which can itself lead to secondary infections - there can be a great many head lice per human head.

The spread of the Head Louse is by direct contact with an infected person.

The female Head Louse lays her eggs and "glues" them to the shafts of hair close to the scalp and the empty egg shells, which we call “nits”,  cling to the hair and are usually the first clue we have that a head louse has taken residence and spawned a family of head lice.

The Head Louse grows through three stages - nit, nymph and Head Louse. The "nymph" sheds its skin three times over ten days before reaching adulthood.

Each Head louse grows to about 3mm, is well camoflaged and has six legs each of which is equipped with a large claw to grasp individual hairs enabling the Head Louse to move very quickly across the head.

A Head Louse has a life span of around 35 days  - 25 of which are in adult form.

Female Head Lice outnumber male head lice by around four to one and each female Head Louse lays between six to eight eggs per day.

Once you are aware of Head lice, it is tempting to blame recent meetings or events for the infestation but, as itching doesn’t normally occur until a head has been infested for a month or two, we should understand that the head louse can just as easily hop onto your head on a crowded  bus and then onto your child as you play with them or tuck them into bed and from your child to their playmates at school - it doesn’t always begin in the schoolyard or with other peoples children!

It is unlikely that only one member of a family will be host to a head louse infestation - the whole family should therefore be treated as early as possible.