What are head lice?

Head lice are small, parasitic insects which commonly live on the scalp and neck hairs of their human host.
Anyone can get head lice, and given the chance, head lice move from head to head without discrimination. People get head lice from direct hair to hair contact with another person who has head lice. Their presence is not caused by a lack of hygiene. Head lice can only crawl from one host to another, as they do not have wings or strong jumping legs. Head lice may be transferred with shared combs, hats and other hair accessories. They may also remain on bedding or upholstered furniture for a brief period of time.

The colour of head lice varies from whitish-brown to reddish-brown. Without magnification and suitable experience, they may be difficult to correctly distinguish from other material caught in the hair.

Head lice derive nutrients by biting the scalp and feeding on blood every 4-5 hours. They cannot survive for more than a day or so at room temperature without ready access to a person’s blood.

During their lifetime, head lice can lay up to 200 eggs (commonly known as nits), which they glue to the hair shaft near the scalp. The eggs remain glued to the hair until they hatch, approximately 10 days after being laid. Head lice start to lay eggs around 1 week after hatching. They have a life span of approximately 6 weeks.

 

The Life Cycle of Head Lice
 
 

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1. Egg (or "nit") is laid on hair shaft.
2. Louse emerges after 6-7 days.
3. First moult 2 days after hatching.
4. Second moult 5 days after hatching.
5. Third moult 10 days after hatching.
6. Emerging from their third moult as adult lice, the female and slightly similar male begin to reproduce.
7. Female lays first egg 1 or 2 days after mating.
8. Female can lay approximately 3 to 8 eggs per day for the next 16 days.
9. Having lived 32 to 35 days the louse dies.

Detection of lice and nits

An itchy scalp may be a sign that a person has head lice, although not all people who have head lice actually feel an itch. Lice bites on the scalp are particularly irritating to children, leading to scratching, which is often the only sign of infestation. Once the scratching becomes noticeable, the infestation is usually well established. Adults may be desensitised, and can carry head lice without realising it.

Lice eggs, commonly known as nits, hatch about one week after being laid and are often easier to see than lice. Nits are about the size of a grain of salt and feel gritty to the touch when fingers are run though the hair. Live eggs are normally glued to the hair shaft near the scalp. Eggs found further along the hair shaft are most likely hatched, or dead.
The Robi Comb Pro has a detection mode to help you find lice in the hair. Turn the device on and comb the hair close to the roots. A change or cessation of the buzzing sound indicates that a louse has been detected or destroyed. Use the included magnify glass to make sure it a louse and not another partical caught in the hair.

Treatment of head lice infestations

Are head lice resistant to insecticides?
International research has shown that head lice are able to develop genetic resistance to some of the insecticides contained in conventional lice shampoos, rendering these treatments ineffective. As a consequence, many shampoos are made with more potent insecticides, which can sometimes cause burning to the scalp, or cause other allergic or chemical reactions. There are some natural lice-shampoos available which are effective.

Mechanical removal

Combing to mechanically removing lice and nits can be an effective method of controlling and eventually eliminating an infestation. Use illumination, magnification and a good louse or nit comb on a daily basis during an infestation to locate and remove lice.

Treating lice with the Robi Comb Pro

Robi Comb is a small electronic comb with metal coated teeth, powered by a single AA battery. As the comb slides through a child's hair, it makes a soft humming sound until it encounters a louse. At that time, the sound stops and a small electrical charge passes from one of the comb's teeth through the louse to the next tooth, killing the louse. Using the small brush included in the Robi Comb package, the user removes the dead louse from the comb's teeth and resumes combing.