Scabies

By Roland Larrabee, M.D.

Scabies (pronounced: skay-beez) is an infection that affects the skin. The infection is caused by tiny mites (they need a microscope to be seen) called Sarcoptes scabiei. These mites burrow into the top layer of human skin to lay their eggs. The burrows sometimes appear as short, wavy, reddish, or darkened lines on the skin's surface, especially around the wrists and between the fingers. A person with scabies can also develop a bumpy red rash.

The most common symptom of scabies is severe itching, which may be worse at night or after a hot bath. A scabies infection begins as small, itchy bumps, blisters, or pus-filled bumps that break when you scratch them. Itchy skin may become thick, scaly, scabbed, and crisscrossed with scratch marks.

The areas of the body most commonly affected by scabies are the hands and feet (especially the webs of skin between the fingers and toes), the inner part of the wrists, and the folds under the arms. It may also affect other areas of the body, particularly the elbows and the areas around the breasts, genitals, navel, and buttocks.

If a person with scabies scratches the itchy areas of skin, it increases the chance that the injured skin will also be infected by bacteria. Impetigo, a bacterial skin infection, may occur in skin that is already infected with scabies.

Scabies is contagious from person to person. Scabies mites are usually transmitted by skin-to-skin contact (especially among family members) and also by sexual partners. Some doctors believe that mites can live as long as 2 to 3 days in clothing, bedding, or dust, making it possible to catch scabies from people who share the same infected bed, linens, or towels.

Scabies spreads more easily in crowded conditions - like child-care centers and college dorms - where people tend to be in close contact with each other.

It may take up to 4 to 6 weeks after infection for symptoms to appear in a person who's never had scabies before. In people who have had scabies previously, symptoms may appear in just a few days.

Practicing good hygiene is the best way to prevent getting scabies. Take showers or baths daily; wash your hands frequently, especially before eating; and wear clean clothing. Though it can be tempting, try not to share clothing with friends.

If someone in your family is being treated for scabies, all other household members should be treated, too. Clothing, sheets, and towels should be washed in hot water. Each room in the house should be vacuumed, and the vacuum cleaner bag should then be thrown away.

Scabies infections need to be treated by a doctor. Call your doctor or dermatologist any time you have a skin itch that will not go away, especially if the itch is worse at night and seems to center around the wrists or the webbed part of the fingers.

If your doctor suspects you have scabies, he or she may scrape a small part of the affected skin and examine the scrapings under a microscope for signs of scabies mites.

Doctors treat scabies by prescribing a medicated cream or lotion. The cream will need to be applied all over the body (except the face, eyes, and mouth), and usually must remain on the skin for 8 to 12 hours before it can be washed off. After applying it, don't wash your hands - scabies mites love the area between the fingers! Sometimes, the treatment needs to be repeated in 1 week.

If you develop a bacterial skin infection such as impetigo in addition to the scabies infection, your doctor may prescribe antibiotics. The doctor may also prescribe an antihistamine to treat itching and a cream like hydrocortisone to help the rash go away faster and treat the itching.