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Lice are tiny, wingless, parasitic insects that feed on your blood. This itchy infestation is easily spread — especially by school children — through close personal contact and by sharing personal belongings.

Several types of lice exist:

• Head lice. These lice develop on your scalp. They're easiest to see at the nape of your neck and over your ears. Small eggs (nits) produced by lice attach to your hair shafts. The eggs hatch in about one week, resulting in more lice.
• Body lice. These lice spend most of their time in the seams and folds of your clothing. Body lice are often spread by direct contact with infected clothing or bedding or with an infected person. In rare cases, body lice may carry diseases.
• Pubic lice. Commonly called crabs, these lice occur on the skin and hair of your pubic area and on eyelashes. Sexual contact or contact with infected clothing, bedding or even toilet seats can spread pubic lice.

You or your child can have good personal hygiene habits and still get lice. Unless treated properly, this vexing condition can become a recurring problem.

Signs and symptoms of lice include:

• Intense itching.
• Lice on the scalp, the body, clothing, or pubic or other body hair. Lice can be up to 1/8 inch (3 millimeters) in size.
• Lice eggs (nits) on hair shafts. Nits resemble tiny pussy willow buds. Nits can be mistaken for dandruff, but unlike dandruff, they can't be easily brushed out of hair.
• Small, red bumps on the scalp, neck and shoulders.

You can get lice by coming into contact with either lice or their eggs. Eggs hatch in about one week. Lice can't fly or walk on the ground. They spread by:

• Head-to-head or body-to-body contact. This may occur as children or family members play or interact closely together.
• Close proximity of stored belongings. Storing clothing next to each other in closets, lockers or on side-by-side hooks at school, or storing personal items such as pillows, blankets, combs and stuffed toys in close proximity at home can permit lice to spread.
• Sharing items. These may include clothing, headphones, brushes, combs, hair decorations, towels, blankets, pillows and stuffed toys.
• Contact with contaminated furniture. Lying on a bed, sitting in furniture or even using a toilet seat recently used by someone infected with lice can spread them. Head lice live for up to two days off the body.
• Sexual contact. All three forms of lice can spread in this manner.

Usually you can get rid of lice by taking self-care steps that include using nonprescription shampoo that's specifically formulated to kill lice. However, if nonprescription shampoo doesn't kill the lice, see your doctor. Your doctor can prescribe a stronger, prescription shampoo. If you're pregnant, don't use any anti-lice shampoo until after talking to your doctor. The scratching that results from lice can sometimes produce hives or skin abrasions. If these become infected, see your doctor.

If nonprescription lotion or shampoo doesn't kill the lice, your doctor can prescribe a stronger shampoo or lotion. Malathion (Ovide) has been re-approved as a prescription drug for treating head lice. Malathion is flammable, so keep it away from heat sources such as hair dryers, electric curlers and cigarettes. If you're pregnant or breast-feeding, talk to your doctor before using this product.

Another type of prescription treatment for lice contains the medication lindane (Kwell). Your doctor may not recommend using lindane for people who weigh less than 110 pounds, have used it in the past few months or for women who are breast-feeding. Side effects may include skin irritation and seizures.

Use these medications as directed; applying too much can cause red, irritated skin.

Whether you use over-the-counter or prescription shampoo to kill lice, much of the treatment involves self-care steps you can take at home to make sure all the nits are removed and that all clothing, bedding, personal items and furniture are decontaminated. In most cases, killing lice on your body isn't difficult. The challenge is making sure you get rid of all the nits and avoiding contact with other lice at home or school.

It's difficult to prevent the spread of head lice among children in day care and in school settings. There's so much close contact among children and their belongings that lice can spread easily. It's no reflection on your hygiene habits or those of your children, and it's not a failure on your part as a parent if your child gets head lice. The best approach is simply to take thorough steps to get rid of the lice — and their eggs — so that you don't have more lice to deal with.

You can ask your child not to share hats, scarves, coats, combs, brushes, hair decorations and other personal belongings at school. But it's not realistic to expect that you and your child can eliminate all the types of contact that may result in the spread of lice.

Your child may have nits in his or her hair but not necessarily develop a case of head lice. Some nits are empty eggs. However, nits that are found within 1/4 inch of the scalp should be treated — even if you find only one — to prevent the possibility of hatching. Nits that are farther away from the scalp are probably from an old infestation and don't need to be treated.

You can get rid of lice with a patient, thorough approach that involves cleaning yourself or your child and any personal belongings that may be contaminated.

These steps may help you eliminate lice infestations:

• Use lotions and shampoos. Choose from among several over-the-counter lotions and shampoos (Nix, Rid, others) designed to kill lice. Apply the product according to package instructions. You may need to repeat treatment with the lotion or shampoo in seven to 10 days. These lotions and shampoos typically aren't recommended for children under age 2.
• After shampoo treatment, rinse your hair with vinegar. Grasp a lock of hair with a cloth saturated with vinegar and strip the lock downward to remove nits. Repeat until you've treated all the hair in this way. Or soak hair with vinegar and leave it on for a few minutes before combing. Then towel-dry the hair. These methods can help remove nits from the hair shaft. Cutting hair very short can also help.
• Comb wet hair. Use a fine-toothed or nit comb to physically remove the lice from wet hair. Repeat every three to four days for at least two weeks. This method may be used in combination with other treatments and is usually recommended as the first-line treatment for children under age 2.
• Wash contaminated items. Wash bedding, stuffed animals, clothing and hats with hot, soapy water — at least 130 F — and dry them at high heat for at least 20 minutes.
• Seal unwashable items. Place them in an airtight bag for two weeks.
• Vacuum. Give the floor and furniture a good vacuuming.
• Cover furniture. Use a plastic painter's dropcloth to cover furniture for two weeks to prevent acquiring another case of lice. Do this only if you don't have toddlers who may risk suffocation if they become tangled in a plastic sheet.
• Wash combs and brushes. Use very hot, soapy water — at least 130 F — or soak them in rubbing alcohol for an hour.