Your Health A-Z

Headlice

Head lice (Pediculus humanus capitis) are about the size of a sesame seed, and can easily be seen, although they hide quickly when exposed to light.

Head lice (Pediculus humanus capitis) are about the size of a sesame seed, and can easily be seen, although they hide quickly when exposed to light. They are wingless, parasitic insects that live and feed on blood from the scalp.

Lice can't jump or fly, but crawl from head to head. The eggs of head lice (nits) can be seen as little white specks, glued to the scalp hairs.

What causes it?

Children are more inclined to get lice because they have frequent head-to-head contact, such as sharing secrets or when playing games or sport. It is sometimes transmitted by sharing items such as combs and hats and having contact with contaminated furniture such as lying on a bed or sitting in furniture recently used by someone infected by lice. Head lice can live up to two days off the body
Contrary to popular belief, contracting lice is not related to poor hygiene – in fact, head lice are thought to prefer clean hair to dirty hair! However, good hygiene can combat body lice – a different variety, and seldom a problem in children.
If your child has lice, you have to notify the school.

What are the symptoms?

Children may hardly notice head lice or may have only a vague scalp irritation in the beginning. It's easiest to spot them at the neckline and behind the ears. The adult louse feeds on blood by biting into the scalp every four hours or so.
A lice infestation can be asymptomatic for two months before itchiness of the scalp occurs. Itchy papules develop and these often become infected from scratching, resulting in infection of the scalp. The lymph nodes at the back of the head and in the neck are frequently enlarged. The eyelids can also be involved.

In adolescents, pubic and axillary hair may be infested.

Other symptoms include: a tickling sensation like something is crawling in your hair, intense itching that causes red bumps due to an allergic reaction to the saliva that lice inject while feeding, and lice nits that resemble tiny buds which can be mistaken for dandruff.

How is it diagnosed?

The doctor will diagnose head lice by using a special light, called Wood's light under which the nits appear pale blue.
Using a fine-toothed comb is also another effective way of identifying head lice. Stroke it from the crown of your head downward over the scalp at least twice. However, finding nits this way doesn't mean that there is a live active infestation.
The best way to identify an infestation is if you find a live louse.

How is it treated?

The most common treatment for head lice is to kill the adults with an insecticidal shampoo and to clear out the nits with a special fine-toothed comb. Of the medications for lice, permethrin is t effective, is pleasant to use, and is available over the counter. For best results, follow the directions exactly. Other family members should be treated too. About 60% of infected children have relatives who carry lice.

Malathion 0.4 per cent in alcohol is a cheap, safe and effective treatment. This kills lice as well as nits, so that the hair need not be combed to remove nits.

However, insecticides present two problems. Lice develop resistance to them and after a while they become ineffective. To get around this , the formulas are made stronger, which means that children are exposed to more potentially harmful chemicals and insecticides.

The locally marketed Controlice range is a non-toxic alternative. Controlice Hair Hygiene is a clinically tested formula with a natural oil base that contains no chemicals or poison but kills head lice effectively.

Controlice Head Rinse Lotion is odourless and colourless. The dimethicone-based formula kills the lice mechanically by wrapping them up. The lotion is left on overnight and washed out with shampoos the next morning. Lice cannot get resistant to these formulas. It is important to repeat head lice treatments within a seven day period to prevent re-infestation.

To eliminate all lice and successfully prevent re-infection, wash all clothing, towels and bed linen in hot, soapy water, and dry them in a hot dryer. You can also disinfect bedding and other items such as hats and clothing by placing them in a sealed plastic bag for 14 days; the nits will hatch in about a week and die of starvation. Brushes and combs can be disinfected by soaking them in hot, soapy water for 10 minutes.

If you prefer to avoid the use of insecticides, try a 'combing only' technique. Wash the hair with an ordinary shampoo and conditioner and leave wet. With a fine-toothed comb, stroke slowly outward from the roots through one lock of hair at a time. Lice will land on the back of the comb, get caught between the teeth, or fall off. Space at least 30 strokes over the head. Repeat every three days. Because new-born lice do not lay eggs for the first week, all lice should disappear after about two weeks of combing.

When to call your doctor?

Most lice can be treated with non prescription shampoo. However, if the treatment does not work and symptoms become worse contact your doctor who will be able to prescribe something stronger.

If you are pregnant don't use any treatment without speaking to your doctor first. If the areas on your scalp become infected due to scratching speak to your doctor.

Preventing head lice

Prevention of head lice is difficult, especially among children, since lice spread quickly from head to head. If you discover lice on your child, notify school or day-care authorities immediately, since classmates are likely to be infected. Infected children should be kept home from school until they are treated.

Here are some tips on preventing lice:

  • Teach children not to share personal items such as brushes, combs and caps
  • Wash hairbrushes, combs, hair clips and bands in very hot, soapy water, or soak them in rubbing alcohol for an hour at least once a week
  • In environments where children are together parents and adults should become familiar with the symptoms of head lice and treat infected children as soon as possible to prevent the spread of lice
  • Tying back long hair can prevent the spread of lice and weekly inspection of hair can help you detect any lice early before infestation occurs

The information provided in this article was correct at the time of publishing. At Mediclinic we endeavour to provide our patients and readers with accurate and reliable information, which is why we continually review and update our content. However, due to the dynamic nature of clinical information and medicine, some information may from time to time become outdated prior to revision.