Lice are flat, wingless parasites the size of a sesame seed that live on the body and cause skin inflammation by biting and by sucking blood. Three types of lice affect humans. Head lice (Pediculus humanus var. capitis) live on and suck blood from the scalp, causing severe itching. These lice pose a major public health problem in the United States, especially with school-age children. It’s estimated that about 16,000 new cases of head licethe most common lice infestationoccur every day.
Pubic lice (Phthirus pubis), also known as crabs because of their crablike shape, live in the pubic area. These tiny parasites are passed through sexual contact or lice-infested bedding or clothing. They attach firmly to the hair follicles in the pubic area and feed off human blood, causing an unrelenting itch.
Body lice (Pediculus humanus var. corporis) live in the seams of clothing, usually on people who don’t change their clothes often enough. The lice attach to the body to feed, typically causing lesions on the shoulders, buttocks, and abdomen.
Symptoms of Lice
- Extremely itchy scalp
- Presence of nits (eggs) on hair near the scalp
- Presence of tiny insects, usually at the base of the neck or behind the ears
- Enlarged lymph glands at the back of the scalp (severe cases)
Pubic lice (crabs)
- Uncomfortable itching and scratching in the groin area, often intense
- Presence of tiny nits in the crotch area
- Red bites on the skin, particularly the buttocks and trunk
- The presence of nits in clothing, particularly the underwear. When they need to feed, lice leave clothing for the body.
What Causes Lice?
Lice are often transmitted in overcrowded or unhygienic environments. But even good hygiene doesn’t ensure protection against head lice infestation. Head lice seem to prefer feeding on clean scalps, for example. An outbreak can start merely by one infected individual coming into close contact with others or sharing with them a hat, hairbrush, comb, pillows, blankets or clothing.
If mating occurs, female lice can lay 50 to 100 eggs at a rate of six eggs per day. These eggs, or nits, are tiny translucent specks that look like dandruff and cling firmly to hair shafts. They hatch in 8 to 10 days and reach maturity in 18 days. To survive, lice pierce the skin and feed off human blood. This leads to skin inflammation and intense itching for the victim.
What If You Do Nothing?
If lice are not treated, they can spread quickly. The itching can also be intolerable.
Home Remedies for Lice
- Apply a medicated shampoo or lotion—with care. For head lice and pubic lice, several over-the-counter products are available—among them Nix (which contains permethrin) and Rid and A-200 (which contain insecticides called pyrethrins). If your child has asthma or allergies, consult your physician before using any lice shampoos. It’s important to follow label directions precisely. Do not repeat a treatment simply because itching doesn’t stop immediately. The itching from extant lesions may persist for a few days after treatment, even though the lice have been eliminated.
- Remove the nits. Nits glue themselves to hair shafts so securely that ordinary washing and brushing will not remove them. A fine-tooth comb must be used to pull out the dead nits from the hair. To loosen them from the hair shafts, use a mixture of half vinegar and half rubbing alcohol and massage it into the hair before combing. Part the hair in one-inch sections and begin removing all nits. Most are found in the hair behind the ears and at the base of the neck. It’s a time-consuming task, but you must be thorough; nits are not always killed with topical medications, and any survivors that aren’t removed may reach maturity and start the reinfestation.
- Clean thoroughly. Wash all sheets, blankets, and pillowcases in extremely hot, soapy water. Dry at high heat for 20 minutes or longer. If possible, iron all clothing and linen. For clothing or toys that can’t be washed, put them in plastic bags and seal them securely for three weeks. Thoroughly vacuum all rugs, furniture, floors and mattresses; don’t forget your car.
- Sanitize. Soak all hairbrushes and combs in rubbing alcohol for 10 minutes.
- Keep checking for lice. Everyone living in the home should be inspected daily for lice. Anyone who develops scalp sores or itching should receive a dose of medicated shampoo, even if lice or nits are not seen in the scalp.
- Don’t share combs or hairbrushes. Sharing grooming items is a quick way to transmit lice.
- Wash often. Bathe and shampoo daily, and put clothes in the laundry after a day of wear.
- Inspect children regularly. Check especially for head lice. The nape of the neck and behind the ears are prime spots for nits and lice.
- Notify others. If you or your child has lice, notify parents of school children that lice have been found. Adults should also inform sexual partners and co-workers.
- Avoid sex with infected people. Lice are quickly spread by sexual contact—and while the use of a condom can prevent sexually transmitted diseases caused by bacteria or viruses, it won’t prevent lice from spreading.
- Be alert to other sources of infection. Lice are often found in car seats, headrests, theater and airline seats, and stereo headphones.
Beyond Home Remedies: When To Call Your Doctor
Contact your physician if itching interferes with sleep, if the rash has not cleared up one week after treatment, if new nits appear in the hair or eyebrows, or if sores appear infected. Also contact your physician if you or your sexual partner has symptoms of lice.
If an over-the-counter treatments fail to eradicate lice, talk to your doctor.
What Your Doctor Will Do
After a close examination your doctor will remove any lice from the eye area. If nonprescription products don’t eliminate the lice, your doctor may recommend a prescription product. Prescription shampoos containing two powerful insecticides—lindane (usually sold under the name Kwell) and malalthion (brand name: Ovide)—are effective, but are also highly toxic, especially for young children. Directions for using them must be followed very carefully.
The Complete Home Wellness Handbook
John Edward Swartzberg, M.D., F.A.C.P., Sheldon Margen, M.D., and the editors of the UC Berkeley Wellness Letter
Updated by Remedy Health Media