Skip to content
My WebMD Sign In, Sign Up

Skin Problems & Treatments Health Center

Scabies - Cause

Scabies is caused by the mitecamera.gifSarcoptes scabiei. Scabies mites are attracted to the warmth and smell of humans. Female mites burrow into the skin, creating small, threadlike tunnels that you can sometimes see. The mites lay eggs and leave feces in these tunnels.

How scabies is spread

  • Scabies usually is spread by close, intimate contact, such as sleeping in the same bed with or touching someone who has scabies. The scabies mite cannot fly or jump, and it moves very slowly.
  • Scabies mites only live for several days away from human skin. During this time, the mites may spread to other people. Mites usually spread through skin-to-skin contact. But they can also spread from contact with clothing, bed linens, and other household and personal items.
  • A mite burrows very quickly under the skin, especially in areas where it is rough or wrinkled, such as the elbows, knuckles, and knees. Touching or scratching an area that is infested with mites can spread them to other parts of the body.
  • After burrowing under the skin, a female mite lays eggs before she dies. The eggs hatch into larvae several days later. These larvae move to the skin's surface and become adults within about 2 weeks. This cycle continues until the mites are killed.

The scabies mite that infests humans does not live on dogs or other pets. And animal-transmitted scabies mites do not survive or reproduce on humans. But they can live long enough on humans to cause itchy hives or raised bumps that last a few days.

Contagious and incubation periods

Scabies is contagious. If you have scabies, you can spread mites to other people before and after you have symptoms, for as long as you remain infested and untreated. After your first infestation, several weeks may pass before you have symptoms. You are contagious during this time, which is known as the incubation period.

If you ever become infested with mites again, it will likely take only 2 or 3 days for you to notice symptoms.

1

WebMD Medical Reference from Healthwise

Last Updated: March 14, 2011
This information is not intended to replace the advice of a doctor. Healthwise disclaims any liability for the decisions you make based on this information.
Next Article:

Today on WebMD

Cleansing skin
Article
Contact Dermatitis
Evaluator
 
woman showing eczema to dermatologist
Tool
mosquito bite
Q&A
 
itchy skin
Article
shingles rash on skin
Article
 
woman with skin tag
Quiz
Harvest mite
Slideshow
 
woman washing her hair in sink
Video
close up of womans bare neck
Tools
 
Feet
Slideshow
woman with face cream
Quiz