What is it?
Scabies is an itchy skin condition caused by a tiny burrowing mite called Sarcoptes scabiei. The presence of the mite leads to intense itching in the area of its burrows. The urge to scratch may be especially strong while you're in bed at night.
Scabies is contagious and can spread quickly through close physical contact in a family, child care group, school class or nursing home. Because of the contagious nature of scabies, doctors often recommend treatment for entire families or contact groups to eliminate the mite.
Take heart in that scabies is readily treated. Medications applied to your skin kill the mites that cause scabies, although you may still experience some itching for several weeks.
Scabies signs and symptoms include:
- Itching, often severe and usually worse at night
- Thin, irregular burrow tracks made up of tiny blisters or bumps on your skin
The burrows or tracks typically appear in folds of your skin. Though almost any part of your body may be involved, in adults scabies is most often found:
- Between fingers
- In armpits
- Around your waist
- Along the insides of wrists
- On your inner elbow
- On the soles of your feet
- Around breasts
- Around the male genital area
- On buttocks
- On knees
- On shoulder blades
In children, common sites of infestation include the:
- Palms of the hands
- Soles of the feet
The eight-legged mite that causes scabies in humans is microscopic. The female mite burrows just beneath your skin and produces a tunnel in which it deposits eggs. The eggs mature in 21 days, and the new mites work their way to the surface of your skin, where they mature and can spread to other areas of your skin or to the skin of other people. The itching of scabies results from your body's allergic reaction to the mites, their eggs and their waste.
Close physical contact and, less often, sharing clothing or bedding with an infected person can spread the mites.
Dogs, cats and humans all are affected by their own distinct species of mite. Each species of mite prefers one specific type of host and doesn't live long away from that preferred host. So humans may have a temporary skin reaction from contact with the animal scabies mite. But people are unlikely to develop full-blown scabies from this source, as they might from contact with the human scabies mite.
Vigorous scratching can break your skin and allow a secondary bacterial infection such as impetigo to occur. Impetigo is a superficial infection of the skin that's caused most often by staph (staphylococci) bacteria or occasionally by strep (streptococci) bacteria.
A more severe form of scabies, called crusted scabies, may affect certain high-risk groups, including:
- People with chronic health conditions that weaken the immune system, such as HIV or chronic leukemia
- People who are very ill, such as people in hospitals or nursing facilities
- Older people in nursing homes
Crusted scabies tends to be crusty and scaly, and covers large areas of the body. It's very contagious and can be hard to treat.
To diagnose scabies, your doctor examines your skin, looking for signs of mites, including the characteristic burrows. When your doctor locates a mite burrow, he or she may take a scraping from that area of your skin to examine under a microscope. The microscopic examination can determine the presence of mites or their eggs.