Head Lice Infestation (Pediculosis)


Head lice infestation (pediculosis), one of the most common contagious childhood diseases are caused by barely visible insects found almost exclusively on the human scalp. Contrary to popular belief, head lice infestation has little to do with personal hygiene. In fact, head lice are totally non-discriminating, and can infest people of any lifestyle, age, race, or socio-economic status. Since lice multiply and spread quickly from host to host.

What do head lice look like and how do they grow?

Head lice are grayish in color and are barely visible to the naked eye. Identifying lice can be difficult as they move very rapidly on six legs. Lice require warmth and humidity to survive, and so tend to be most concentrated around the back of the host’s head and behind the ears. A single female may lay up to 150 eggs, or “nits”, during her lifetime. Nits are silvery-white in color, oval in shape, and may look to the naked eye like tiny grains of sand cemented to the hair shaft. Nits are smaller than adult lice but are generally easier to identify because they’re more numerous and don’t move. Seven to nine days after being laid, the nits hatch and give birth to young lice who then start their own life cycle.

Common questions about lice transmission

Question: Is the presence of lice a sign of poor personal hygiene?

Answer: No, head lice seem to prefer a clean scalp; and otherwise show no particular preference for a human host’s sex, race, age or socio-economic status.

Question: Are children only susceptible?

Answer: No, lice show no preference for children over adults. However, infestation is more common among children between 3 and 10 years because of their tendency to be in close contact with others – especially at school, day cares, buses, camps and playgrounds.

Question: Does long hair encourage infestation?

Answer: No, since head lice are only interested in the immediate area of the scalp, cutting the hair will neither prevent nor alleviate infestation.

Question: Can Lice be contracted from plants, animals, and pets?

Answer: No, humans are the only hosts head lice survive on. Head lice cannot live on animals, pets or plants.

Question: Can lice jump or fly from one person to another?

Answer: Head lice have no wings, they can only crawl – so transmission comes only from direct contact with other infested people or their belongings. Indirect transmission can occur through sharing personal articles that come in contact with the scalp, such as hats, scarves, hair accessories, headgear, headphones.

How is head lice infestation detected?

The main symptoms of head lice infestation are itching and irritation of the scalp. The itching is usually persistent, and more intense during the night. Head lice infestation can be diagnosed by confirming the presence of living lice or viable nits on the head. They are visible to the naked eye, or with the use of a magnifying glass. Although nits are generally easier to detect than lice, they can be confused with specks of dandruff, skin debris, or hair product residue. This mistake can be avoided by testing the adhesiveness of the specks to the hair shaft. Unlike other substances, nits cannot be removed easily with fingernails or by washing the hair. It’s important to be aware that the mere presence of nits in the hair does not necessarily indicate current head lice infestation.

What happens if lice are found on a child?

If living head lice or viable nits are found on a student, the school authorities usually send the infested child home with a letter to the child’s parents, explaining what the problem is and suggesting that the child see a pharmacist or physician for treatment. Parents and children are usually assured that they are not to blame for head lice infestation, that there’s no need for panic, anxiety, or embarrassment, and that the problem can be resolved quickly and effectively with the proper treatment and precautionary measures.

If more than one student is found to have head pediculosis, a sample of children from each grade should be examined by the nurse in order to estimate the degree of the outbreak. If the infestation becomes difficult to control, the nurse may need assistance from the local public health department to fully evaluate and control the problem.

How are head lice infestations treated?

There are three important treatment components:

  1. Pediculicidal treatment
    A variety of pediculicidal treatments are available in the form of shampoos, creme rinses, and aerosols. Properly administered, the application usually kills all lice, but some nits may survive. Most pediculicidal treatments require a second application after a given period of time, in order to wipe out any lice which may have hatched from surviving nits. The specific treatment should be discussed with the child’s doctor, nurse, or pharmacist. For successful treatment, instructions for how to use the product must be strictly adhered to. Misuse or repeated dosages of pediculicides can render treatment ineffective, make the problem worse, or even cause harm.
  2. Use of a fine-toothed comb after pediculicidal treatment
    The use of a special comb to remove nits and head lice after the application of a pediculicide is essential to successfully complete treatment. Immediately after rinsing the pediculicide from the hair, the fine-toothed comb should be used on a small lock of hair at a time, combing towards the scalp and then back, to remove all nits and lice. This operation should take about two hours and requires a great deal of patience but must be done in order to avoid re-infestation.
  3. Disinfection of items that may have been in contact with an infested child
    Head lice can live for about 48 hours away from the host, and nits can survive for up to two weeks. So another important precaution for preventing reinfestation (or an infestation of other family members) involves the disinfection of personal articles and other items that are likely to have come in contact with the scalp. These may include hats, scarves, hair accessories, towels, and bedding items. Clothing that may have come in contact with the patient’s hair should be washed in very hot water and dried in the hottest cycle of the dryer for at least 20 minutes. The same should be done for towels and bedding items. Brushes and combs can be disinfected by soaking them in hot water for 10 minutes. Items that cannot be washed should be either dry-cleaned, ironed with a hot iron, or sealed in a plastic bag for two weeks.

What about family and other close contacts?

In order to reduce chances of re-infestation and to control the outbreak of head lice, it’s important that anyone who’s been in close contact with the infected person – whether family members, schoolmates, or friends – be informed, examined, and if necessary, treated. Any other infested individuals should be treated at the same time.

Schools Exclusion and “No-Nit” policies

According to the Canadian Pediatric Society and the American Academy of Pediatrics, there is no reason to exclude a child with head lice from school or child care. In fact “no-nit” policies are discouraged. However, a full course of the appropriate treatment and avoiding close head-to-head activities are recommended.

Read more: Headaches in Children 

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Pediatrician DR.PAUL Roumeliotis is certified by the American Board of Pediatrics and Royal College of Physicians and Surgeons of Canada. The information provided above is designed to be an educational aid only. It is not intended to replace the advice and care of your child’s physician, nor is it intended to be used for medical diagnosis or treatment. If you suspect that your child has a medical condition always consult a physician.