Head lice alert

Head lice alert – includes related information

Known since ancient times, the head louse – Pediculus capitis – is a tiny, six-legged, wingless, greyish insect that infests the scalp and head hair. Lice feed on blood, breeding and laying their eggs on the human scalp. Although annoying, head lice are not a health threat and do not carry diseases (although other forms can transmit disease). Head lice do not jump or fly but get from person to person by scuttling from the hairs of one head to those of another. Having lice does not mean someone is dirty, neglected or poor. Head lice are just as likely to live on rich as on poor people, and they are even said to prefer clean to dirty hair! Reports suggest that lice infestations have become more prevalent in Canada, also indicated by increasing sales of de-lousing agents, although the reason for the lice rise remains unclear. These tiny insects may have developed resistance to the products used to eliminate them.

Recognizing a lousy infestation

Head lice often cause no symptoms although itchiness and scratching – particularly around the hairline and ears – are telltale clues. The itching starts a week or two after infestation begins, as a reaction to many, many louse bites. But many infested people remain unaware of their lousy condition.

Head lice are best detected by sighting a louse and/or its eggs. Chances of finding a live louse are slim because the greyish insect is hard to see, although after a blood meal it becomes rust-coloured. Louse excrement looks like flecks of dust. Glimpsing the discarded shells of louse eggs or “nits” – as white, glistening objects cemented to the hair shaft – is the easiest way to spot an infested head. Nits can be distinguished from dandruff because they are hard to dislodge.

Treatment options: follow the advice carefully

Head lice can be eradicated with louse-killing agents or pediculicides. A thorough hair-washing with a medicated, louse-killing shampoo, or application of an anti-louse rinse at least once, and possibly again a week later, often gets rid of them. Anti-louse products vary in cost and effectiveness. Most kill the insects but only a few completely destroy the eggs. Some products are inappropriate for very young children or those with allergies. Some parents try frequent anti-louse shampooings to prevent head lice, but multiple shampooing is ineffective, promotes insect resistance, is expensive and may be harmful to a young child.

Simply killing the insects is not enough as their eggs stay behind and can hatch 6-10 days later, ready to begin reproducing. It is essential to kill all live eggs too.

No need to panic or stigmatize children

The most important aspect of head lice, from a public health perspective, is panic and misconception in schools and among parents. Authorities and school boards vary in their attitude to louse-ridden children. Some schools send them home and re-admit them only when free of lice, others try to avoid labelling a child as “lousy” and rely on parents to check and keep their offspring louse-free. Some school boards conduct head-checks at frequent intervals, often with the help of volunteer parents.

Preventing lousy reinfestions

Even after lice and nits have been eradicated, re-infestation easily occurs, especially among children who return to environments where others have head lice. Recommendations for preventing repeat infections vary, but most promote regular screening. Some experts suggest that all family members and cohabitants of a louse-infested child (or adult) should be treated at the same time. No longer recommended are the previously rigorous practices of disinfecting all furniture and heroic efforts to de-louse the entire house and car. Massive disinfecting involves a lot of trouble and expense for no proven result. However, most authorities do suggest washing bed linen in hot water and drying it in a hot dryer, as well as dry-cleaning blankets and storing them away from human contact for a week or so. Soaking hairbrushes and combs in a pediculicide and washing hats, scarves and other headgear is also useful. Children should be discouraged from sharing personal items such as hairbrushes, hats and combs. All authorities agree that the single most important anti-louse measure is to check children’s heads regularly for lice and nits.

Lice spread mainly by head-to-head contact

Lice most easily spread from one head to another among children in daycare centres and primary schools, where youngsters play intimately together. Lice are more common in girls than boys, possibly because girls tend to have closer physical contact. Despite sparse evidence, many continue to believe that lice spread by sharing items such as hairbrushes, towels, hats, scarves or combs. But studies do not find that lice get around much that way. For one thing, lice are not likely to abandon the warmth of the scalp and hop onto a scarf or towel. For another, lice cannot live away from their human hosts for more than one hour. They do not lurk in clothing, furniture or bed linen.

Sorting out the anti-lice products

* Permethrin (Nix) – according to a recent analysis in the British Medical Journal – is the most effective delousing product on the market. Recommended by many health departments, this rinse kills not only mature lice, but also the eggs and hatching nymphs. Although one application often suffices, some authorities recommend a repeat application 10 days later to make sure all eggs are obliterated. Permethrin should not be used in people allergic to ragweed or chrysanthemums.

* Lindane (Kwellada) shampoo, the best known and cheapest product, is massaged into the scalp, left on for 4-5 minutes and then rinsed out. The shampooing is repeated one week to 10 days later, to kill emerging nymphs and new adult insects. Kwellada is not recommended for children under age six.

* Pyrethrins, such as “RID” and “R & C” are chrysanthemum products that require a repeat application to kill hatching lice. They should not be used by anyone allergic to ragweed or chrysanthemums (because of cross-sensitizaton).

* Malathion (Prioderm), a cream rinse not used much in Canada, has an unpleasant odour and must be left on the hair longer than other products.

* Step Two (Step II) is a rinse containing formic acid that comes with a steel nit-comb. The combination of rinse plus combing is said to loosen nits but its usefulness remains unproven and some experts say it’s no better than a cheap vinegar rinse (also of dubious help).

COPYRIGHT 1996 Strategic Inc. Communications Ltd.

COPYRIGHT 2004 Gale Group