Ask An Expert: Scabies Treatment

Content provided by the Faculty of the Harvard Medical School

Ask An Expert: Scabies Treatment

Question:

What are scabies, and how do we get rid of them?

Answer:

Scabies is an infestation of the skin caused by a small mite known as Sarcoptes scabiei. Scabies is often hard to detect. It causes an intensely itchy skin rash, and it is contagious. The infestation spreads from one person to another by direct skin-to-skin contact or by sexual contact. It spreads quickly when groups of people live together in close quarters. Anyone can catch scabies.

The mite that causes human scabies is barely visible. Only the female mite causes symptoms in people. A pregnant female mite digs into the skin, making a tunnel in which she lays her eggs. Eventually the female mite dies, but the eggs hatch, and more mites grow and continue the infestation. Within a few weeks, the person develops an allergic reaction with severe itching. The itching is usually worse at night. There is often a rash, with tiny red bumps that look like small insect bites, and visible burrows on the skin.

To make the diagnosis of scabies, your doctor will ask about your health and activities and look for signs of mite infestation on the skin. Identifying the burrows helps confirm the diagnosis. Your doctor may also take scrapings of the affected skin to look for evidence of mites.

What medicines are used to treat scabies? Your doctor might give you permethrin skin cream (Nix, Elimite, Acticin). Sometimes lindane (Hexit, Kwell, Scabene) or crotamiton (Eurax) is recommended. Surface medications should be applied to all areas of the body from the neck down and washed off after eight to 14 hours. In some cases, a second application is necessary. Sometimes scabies is treated with ivermectin (Stromectol) pills, an oral medication. It is given as a single dose followed by a repeat dose two weeks later. The choice of a specific medication is influenced by a person's age, medical history and coexisting medical problems. Anti-itching medications are also sometimes prescribed.

Once the diagnosis is made, all affected people, family members and close contacts should be treated at the same time, even if they have no symptoms. This is to avoid passing the infestation back and forth. It is also suggested that you wash and dry (or dry clean) all clothing and linens.

Diana Post, M.D., is an assistant professor of medicine at Harvard Medical School and a member of the Department of Medicine at Brigham and Women's Hospital.

Last updated:	May 08, 2007