Lice (Pediculosis)

What is it?

Lice are parasitic insects. Several different kinds of lice live on humans. Head lice live on the scalp, and pubic lice live in pubic hair and sometimes on eyelashes. Head lice and pubic lice are actually different species. Head lice can’t live in pubic areas and vice versa. Lice live their entire lives on their human host. As adult and larva, they live by sucking blood from the skin. As they do this they cause skin irritation and itching. Lice lay their eggs by gluing them to the hairs in the region of the body where they live. The eggs are called "nits." Only adult and larval lice can spread from person to person. Nits do not spread. Human lice do not spread disease.

Head lice are a very common problem in children of school age. In fact, in some areas up to half of all children get lice at some time. Because children usually play in very close contact with each other, lice can rapidly spread from one child to another. This can cause a great deal of concern at schools and camps, although lice are not in any way dangerous.

Public lice are most common in sexually active teenagers and adults, where they spread through sexual contact. Another name for pubic lice is "crab lice" or "crabs." Very rarely, younger children can get crab lice on their eyelashes, where they can cause swelling and irritation. Crab lice on the eyelashes are not automatically a sign of sexual abuse.

Many parents are horrified to learn that their children have lice. Parents often worry that this means that they or their children are somehow "not clean," and that their children might get other diseases. It is true that lice living on rats carry the disease typhus, and that other biting insects carry and spread disease, but human lice do not. The main concern in children with lice is to control the itching and discomfort. If children scratch too hard at their scalps they can develop bacterial infections or impetigo (you can also read our Aftercare Instructions on Impetigo). Some children with scalp infections or irritation may develop swollen lymph nodes in their necks. These appear as small lumps under the skin. Sometimes the lymph node swelling is what first calls attention to a problem on the scalp.

The other big concern with head lice is dealing with the school, camp, or daycare, and sometimes with other parents. As we’ve mentioned, lice are not a sign of unclean people or houses, and they aren’t a source of infection. After treatment, some nits still remain on the child’s head. This is not a reason for a child to have to stay home from school, camp, or daycare. You may need to get your doctor to write you a note to that effect.

Pubic lice also do not spread disease themselves. They cause itching and sometimes redness in the pubic area. Pubic lice may also cause swelling of lymph nodes in the groin area. Because pubic lice spread through sexual contact, people who have them may have other sexually transmitted infections as well. Teens with pubic lice should be sure to have tests for other sexually transmitted infections, including HIV. Condoms do not prevent the spread of lice.  Pre-pubertal children who have pubic lice on their eyelashes only do not need testing for sexually transmitted infection unless you or the doctor have reasons to be concerned.

Doctors treat head and pubic lice with the same kinds of medication. Over-the-counter lotions that contain "pyrethrin" or "permethrin" (many brand names) may work in mild cases. Some lice are resistant to these medications, however, so they may not always work well.

Children with more severe cases and those who get lice more than once need a prescription medication. Malathion (Ovide®) 0.5% lotion is the safest available medication. Please follow the package directions carefully. Here is a summary:

• Apply the lotion onto dry hair, and rub it in to completely moisten the hair and skin. Please remember that the lice live down near the skin, so be sure to get it rubbed all the way in. Please wash your hands right away after applying the lotion. Malathion lotion is poisonous if swallowed. It is also flammable, so please don’t use it around fire or while smoking. After you apply the lotion, let the hair dry naturally – not with a hair dryer or any other heat. Please do not cover the hair with anything. Let the medicine stay in the hair and scalp for 8 – 12 hours. After that, please wash the hair with a regular (non-medicated) shampoo. Please be sure to rinse all traces of the lotion out of the hair, and to wash your own and your child’s hands again. Then, you can comb out the dead lice and nits using a fine-toothed comb (often packaged with the medication). Your doctor may recommend that you repeat the medication in 7 -10 days, in order to kill any new lice that hatch out from any surviving eggs.

Lindane (Kwell®, Thionex®) shampoo is also effective. In large or repeated doses it can cause important side effects including seizures, so most doctors avoid it unless there’s no other option. If you are using lindane shampoo, please follow the package directions carefully. Here is a summary

• First wash out any hair styling or conditioning products and remove any braids, beads, or other accessories. Dry the hair. Next, carefully apply the lindane shampoo only to the hair and scalp. Lindane is poisonous and can go through skin, so please avoid getting it on other parts of the child’s body. Please use plastic (not pure latex) gloves while you apply the shampoo. Allow the shampoo to sit on the hair and scalp for 4 minutes, and then rinse it out. Dry the hair with a clean towel. After the hair is completely dry, you can comb out the dead lice and nits using a fine-toothed comb (often packaged with the medication). Your doctor may recommend that you repeat the medication in 7 -10 days, in order to kill any new lice that hatch out from any surviving eggs.

The itching from lice can continue for up to a week after proper treatment. This is normal. It does not mean that the lice are back. Please do not re-apply any medication until you check with your doctor. You can give your child diphenhydramine (dye-fen-hi-drah-meen; Benadryl® and many others) for itching. The main side effect of diphenhydramine is drowsiness, which is actually often helpful to a child whose itching is making him or her frantic.

Because lice do spread from person to person, it will be important for everyone who lives in your child’s house to check for lice and to get treatment if necessary. Lice can spread on such as clothing, bedding, hairbrushes, and other objects. Many doctors recommend washing all the bedding on the same day that you apply the medication, so that the whole house gets a fresh start.

In especially severe cases or under special circumstances, doctors may prescribe an oral medication called ivermectin (Stromectol®). This drug works to kill worms and other internal parasites, and some scientist feel it is promising for treating lice and other skin parasites as well. Testing in children larger than 33 pounds (15 kilograms) shows that the drug is safe. There will be more information on this drug for use in treating lice and scabies over the next few years. An antibiotic called TMP/SMX (Bactrim®, Septra® and many others) can also help in severe cases or in cases which did not get better using only lotion or shampoo. TMP/SMX in combination with permethrin or lindane can increase the rate of cure. You may want to discuss these drugs with your child’s doctor.

Crab lice on the eyelashes of younger children are difficult to treat. Please do not apply any of the medicated lotions on or around the eyes. Many doctors recommend carefully applying petroleum jelly (Vaseline® and others) onto the lashes. This should suffocate the lice and their eggs. Some doctors carefully pluck or cut all the lashes. Please do not try to do this yourself – you could cause injury to your child’s eyes.

As we’ve said, lice are not dangerous themselves. If your child scratches him or herself hard enough to break the skin, s/he might get an infection. Signs of a skin or scalp infection include redness, swelling, pain, or pus draining from sores on the scalp. Also, lymph nodes in the child’s neck might swell and become tender. If any of these things happen, please call your doctor.

Please keep your child home from school, daycare, or camp until you have treated the lice. Children can return to these activities immediately on the day after you apply and comb out the medicine. The medications may leave some nits on the scalp or in the hair. Nits are not contagious. Some schools have "no nit" policies that keep children out of school until all nits are gone. These policies do not help reduce the spread of lice, and they cost children many unnecessary days of school absence. The National Association of School Nurses recommends that children be allowed to return to school after treatment for lice, even if some nits remain.

Some lice are now resistant to some kinds of medications. This is partly because people may treat for lice even when children don’t have them. Even doctors often mistakenly diagnose lice in error. Please be sure that you only use any medication if you or your doctor discover live lice or nits that remain attached to hairs. Also, please be sure to follow your doctor’s instructions for return visits to check for remaining lice. This will insure that your child gets the right amount of medication and misses the least amount of school.

Human lice do not carry diseases to humans. People who have pubic lice (crabs) can also have other sexually transmitted infections (STI’s). If your teen is sexually active, please be sure to counsel him or her about all possible choices. Condoms are the only way to prevent many STI’s. Condoms do not prevent lice or genital warts, however. The only ways to prevent these are either to avoid sexual activity, or have an honest discussion with each potential partner. It can help some teens in their decision-making if you point out that a partner with lice or genital warts got them from someone else, and only by having sex with them. This means that their partner is probably not having sex with just one person.

Having a child with lice can be tiring and frustrating. As badly as you feel for your child, you yourself may feel out of control, inadequate, or even angry – these are normal feelings. Babies and children who have lice are often fussy and irritable, and parents often feel stressed to the breaking point, especially when there are other children or adults to take care of. One of the best things you can do for your child is to be sure you take care of yourself. If possible, try to have other adults take care of your child for an hour or two each day so you can get some rest or just some quiet time. If you get so stressed that you are worried about your child’s safety, call your local Parents’ Anonymous Hotline or visit the Parents Anonymous website to find a group near you.