Scabies is a mite infestation of the skin. The scabies mite, also known as the human itch or mange mite, causes intense itching, and it is contagious. When a person catches scabies, pregnant female mites dig burrows in the skin and lay eggs along the way. After three to eight days, the eggs hatch and the young mites travel up the burrows to the skin surface. There they grow to adulthood and mate, after which the females become pregnant and continue the skin infestation. Once a female mite finishes laying her eggs, she spends the rest of her 2-month life span at the deep end of her tunnel. Mite tunnels may be visible in the skin of a person who has scabies, although intense scratching often distorts their appearance.
Scabies mites can be transmitted by direct skin-to-skin contact with an infected person or by using clothing, blankets, sheets, towels or furniture that has touched an infected person's skin. Scabies easily spreads during the close physical contact of sexual activity. However, scabies also can be passed from person to person in various nonsexual settings in which people live in close quarters, including hospitals, nursing homes, prisons, day-care centers and homes. Anyone can catch scabies, including doctors, nurses, teachers, toddlers and elderly people in wheelchairs. Having scabies is not a sign that someone is dirty, careless or sexually promiscuous.
Worldwide, approximately 300 million new cases of scabies occur each year in men, women and children of all ages and races. Groups that are especially vulnerable to catching scabies include:
Symptoms of scabies include:
Symptoms of scabies are part of the immune system's reaction to the scabies parasite and its waste products. This reaction usually takes a few weeks to develop in people who have never had scabies before. For this reason, people with their first episode of scabies may not develop an itchy rash until two to six weeks after the skin infestation starts. However, in people who have had previous episodes of scabies, the body's reaction is triggered sooner, so itching and rash often begin within one to four days.
Scabies is a very contagious illness that can spread to members of your family and other people who have close physical contact with you. For this reason you should never self-diagnose this illness. You must be examined by a professional.
After reviewing your symptoms and your risk factors (sexual contact, crowded living conditions, high-risk work environment), your doctor will examine your skin. Most often, the diagnosis is made based on skin findings and known exposure or possible exposure to scabies. The doctor looks for bumps between the fingers and toes and for burrows. The doctor also may scrape an area of rash gently to look for the mites or their eggs.
With proper treatment, the rash and intense itching of scabies usually begin to subside within one to two days, although some milder itching can persist for a few weeks.
Without treatment, scabies can be a long-term infestation that can spread to other people. During the course of the illness, persistent scratching can lead to chronic crusting of the skin or to painful secondary skin infections caused by bacteria.
To help prevent scabies:
Your doctor can treat scabies with various topical (applied to the skin) medications, including permethrin (Nix, Elimite), lindane (Kwell, Scabene), crotamiton (Eurax), and, in infants and other sensitive people, sulfur in petroleum. The choice of a specific medication is influenced by a person's age, pregnancy, the presence of coexisting skin conditions and medical history. Scabies medications usually are applied from neck to toe after bathing, allowed to remain on the skin for 8 to 14 hours, and then washed off. In some cases, a second application is necessary, depending on the type of medication used and your symptoms. Ivermectin (Stromectol) is an oral medication that also treats scabies effectively. It is given as a single oral dose followed by a repeat dose 2 weeks later.
To help control itching, simple topical agents such as calamine lotion can be applied. If the itching keeps you awake, diphenhydramine (Benadryl) taken by mouth may be advised.
All sex partners, family members and close contacts of someone with scabies must be treated for the infestation, even if they have no symptoms.
Call your doctor if you have symptoms of scabies or if you have been exposed to someone with scabies.
Also, contact your doctor if you have been diagnosed with scabies and your symptoms have not improved significantly within one week after completing treatment.
If you follow your doctor's directions for using scabies medication, the prognosis is excellent. In most cases, you stop being contagious within 24 hours, and your major symptoms should improve noticeably within 2 days.
Centers for Disease Control and Prevention (CDC)
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Atlanta, GA 30333
National Institute of Allergy and Infectious Diseases (NIAID)
Office of Communications & Public Liaison
6610 Rockledge Drive, MSC 6612
Bethesda, MD 20892-6612
National Institute of Arthritis and Musculoskeletal and Skin Diseases
National Institutes of Health
1 AMS Circle
Bethesda, MD 20892-3675
American Academy of Dermatology
P.O. Box 4014
Schaumburg, IL 60168-4014