An Overview of Head Lice

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Head lice infestation is a common problem. The tiny parasitic insects are most often found behind the ears and near the neckline at the back of the neck. Though troubling, an infestation is not a health hazard and lice are not responsible for the spread of any disease. Over-the-counter treatments and diligent combing to remove lice and eggs are usually effective. There are 6 million to 12 millions cases of head lice in the United States every year, with more in children than adults.

Symptoms

Seeing the head lice is the chief symptom. If you see what looks like little grains of rice moving around in the hair, it is likely that there is a lice infestation. You may also see lice eggs, called nits, on hair shafts.

When you have head lice, you may feel a sensation that something is moving in your hair. Lice are most active after dark and this can lead to difficulty in sleeping. Scalp itching develops due to an allergic reaction to the louse's saliva. This reaction takes time to develop the first time a person has lice, and so you could have lice for four to six weeks before you begin to feel itching. This will come on sooner during a subsequent infestation, as you have already been sensitized.

Scratching can lead to a secondary skin infection and red or pustular sores on the scalp. Swollen lymph nodes in the front and back of the neck can develop due to the allergic reaction to the louse saliva.

Causes

Head lice, Pediculus humanus capitis, are usually spread by direct contact with the head or hair of an infested person. Lice can't fly or jump, they only crawl, so this is the most effective way for them to spread. Children in preschool and daycare, as well as school-age children and their families, are at the most risk.

The spread of lice from objects is possible but is less common. Objects can include hair care items such as combs and brushes, clothing such as hats, and items such as pillows and stuffed animals that come into contact with the hair.

Head lice infestations are less common in African Americans, possibly because the louse prefers a specific hair shaft shape and width. But lice can be found on short, long, curly, or straight hair of any individual.

Many people worry they will be stigmatized if they discover head lice. However, the spread of head lice has nothing to do with personal hygiene or the cleanliness of your home. Lice are found universally in every socioeconomic group.

Diagnosis

A head lice infestation is diagnosed by seeing lice on the person's head. The lice can be in any portion of the life cycle—adults, nymphs, or nits (eggs). You can look for them at home with a lice comb and a magnifying lens. If you are unsure, a doctor can look for lice. If a case of head lice is identified, all household members should be checked.

Finding nits within a quarter inch from the scalp confirms an infestation that needs to be treated, while nits farther from the scalp don't prove there is an active infestation. Nits can be distinguished from dandruff flakes as they are extremely adherent to the hair shaft, whereas dandruff can be easily moved along or away from the hair shaft.

Treatment

The first line of treatment for head lice is an over-the-counter (OTC) anti-lice shampoo. The most common products are Nix (permethrin) and Rid (pyrethrins plus piperonly butoxide). They kill the adult lice and nymphs. Because they don't destroy the nits, they must be reapplied after seven to 10 days when the nits hatch.

OTC treatment is coupled with wet-combing with a fine-toothed lice comb to remove lice and nits. This method may be done on its own without other treatment, but that requires extra diligence to ensure all lice and nits are removed.

If lice are resistant after initial OTC treatment, a physician may prescribe topical medications that include Ovide (malathion), Ulesfia (benzyl alcohol 5 percent), Natroba (spinosad), or Sklice (ivermectin). There are also a couple of oral medications that may be prescribed, but they are not approved by the FDA for that purpose and their use is off-label.

Common home remedies involve smothering lice by coating the hair and scalp with an occlusive agent such as olive oil, petroleum jelly, or mayonnaise, and leaving it on overnight. However, it may be the careful cleaning required when using these agents that lend them any effectiveness. Remedies such as vinegar that are claimed to loosen nits have not been shown to be effective and some may cause hair damage, skin or eye irritation, or other risks.

A variety of essential oil and herbal products are touted, and some such as tea tree oil (melaleuca) and lavender oil preparations and neem seed extract have studies that show they may be effective. The American Academy of Pediatrics cautions that herbal products should not be used on infants and children.

All hair care items, hats, and bedding belonging to the infested person should be cleaned by laundering or vacuuming. There is no need to use fumigant sprays or fog in your home.

Coping

It can be stressful to discover lice and to cope with its emotional, social, and physical ramifications. Take steps to address your anxiety and to reassure your child that this doesn't mean she did something wrong. You can take positive action to make the treatment and combing as non-stressful (and even soothing) as possible.

If your child is infested, communicating with the school and other parents is needed to help stem the spread of lice and ensure everyone exposed is screened. When sharing the news, know that you may run into people who are under the sway of myths and misunderstandings about lice. Be sure to educate yourself so you can communicate accurate information to others.

You may have to adjust your childcare if your child's school or daycare has a "no-nit" policy. The American Academy of Pediatrics and other authorities advise that children can return to school as soon as they start treatment, but some districts and programs still retain a stricter policy.

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