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Scabies (cont.)

What Is the Life Cycle of the Scabies Mite?

The life cycle of the scabies mite starts when the female tunnels (burrows) into the skin and deposits her eggs. Larvae hatch from the eggs within three to 10 days and molt to become nymphs. Nymphs mature into adults that deposit additional eggs and live approximately four weeks. Burrowing and movement of the mites cause intense itching due to a type of allergic reaction to mite proteins. If the person has never been exposed to scabies before, he or she may not show symptoms until four to six weeks after the initial infestation. Individuals who have been exposed in the past usually show symptoms within a few days.

How Long Do Scabies Live Without a Human Host?

The mite can only survive for three days in the environment. Once on a human body, the mite may reproduce; if the infection remains untreated, it can cause symptoms for years.

Where Does Scabies Come From?

Scabies is spread (transmitted) through skin-to-skin contact with a person who carries the mite. The mites often begin to cause symptoms first at the site where they enter the body. Thus, skin transmission during sexual intercourse may cause skin lesions on the penis, vaginal area, or groin. It is important to point out that scabies is not always a sexually transmitted disease (STD) and may be acquired through any skin-to-skin contact. However, in young, sexually active individuals, scabies is usually spread by sexual contact.

Less commonly, scabies infestation can happen through the sharing of clothes and bedding. Theoretically, a person can get scabies from touching something that the mite is on, but that is not a major mode of transmission. The mite only lives for two to three days away from human skin. Human scabies is not spread by contact with animals or pets; however, the human mites may infest pets like dogs and cats and cause itching; the human mites do not multiply on pets and quickly die. The mites that cause sarcoptic mange, or dog or pet scabies, only multiply on pets like dogs and cats; although they may cause itching on humans, they do not multiply on humans and soon die.

Medically Reviewed by a Doctor on 2/22/2016

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Scabies »

Human scabies is an intensely pruritic skin infestation caused by the host-specific mite, Sarcoptes scabiei var hominis.

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