What is it?
Scabies is an infestation of the skin with the microscopic mite Sarcoptes scabei. Infestation is common, found worldwide, and affects people of all races and social classes. Scabies spreads rapidly under crowded conditions where there is frequent skin-to-skin contact between people, such as in hospitals, institutions, childcare facilities, and nursing homes. People with weakened immune systems and the elderly are at risk for a more severe form of scabies, called Norwegian or crusted scabies.
The female scabies mite burrows or tunnels into the outer layer of skin in a tiny red line about a half-inch long and then lays eggs. Such a burrow is usually very hard to see or find on people. Usually the parasite will tend to first locate in the webs between the fingers or toes, around the wrist or about the navel. It can also be commonly found on the back of elbows, the folds or the armpits, the beltline and abdomen, about the creases of the groin, and on the genital organs. Small children, especially babies, often have involvement of the face, scalp, palms of the hands, or soles of the feet, but this would be very unusual in adults.
What are the signs and symptoms of scabies infestation?
- Pimple-like irritations, burrows or rash of the skin, especially the webbing between the fingers; the skin folds on the wrist, elbow, or knee; the penis, the breast, or shoulder blades.
- Intense itching, especially at night and over most of the body.
- Sores on the body caused by scratching. These sores can sometimes become infected with bacteria.
For a person who has never been infested with scabies, symptoms may take four-six weeks to begin. For a person who has had scabies, symptoms appear within several days. You do not become immune to an infestation.
Some people can be carriers and not know it or show it. Tiny blisters can occur on scabies areas and when scratched, small infected sores develop. Although there is a high degree of suspicion for scabies if such skin conditions are present, definite proof of the presence of scabies is based on actually finding and recognizing the parasite. They can be spotted with a hand lens
How is it spread?
Scabies is spread by direct, prolonged, skin-to-skin contact with a person already infested with scabies. Contact must be prolonged (a quick handshake or hug will usually not spread infestation). Infestation is easily spread to sexual partners and household members. Infestation may also occur by sharing clothing, towels, and bedding.
How long will mites live?
Once away from the human body, mites do not survive more than 48-72 hours. When living on a person, an adult female mite can live up to a month.
Can pets spread scabies to humans?
No. Pets become infested with a different kind of scabies mite. If your pet is infested with scabies, (also called mange) and they have close contact with you, the mite can get under your skin and cause itching and skin irritation. However, the mite dies in a couple of days and does not reproduce. The mites may cause you to itch for several days, but you do not need to be treated with special medication to kill the mites. Until your pet is successfully treated, mites can continue to burrow into your skin and cause you to have symptoms.
How is scabies infestation diagnosed?
Diagnosis is most commonly made by looking at the burrows or rash. A skin scraping may be taken to look for mites, eggs, or mite fecal matter to confirm the diagnosis. If a skin scraping or biopsy is taken and returns negative, it is possible that you may still be infested. Typically, there are fewer than 10 mites on the entire body of an infested person; this makes it easy for an infestation to be missed.
Can scabies be treated?
Yes. Several lotions are available to treat scabies. Always follow the directions provided by your physician or the directions on the package insert. Apply lotion to a clean body from the neck down to the toes and left overnight (eight hours). After eight hours, take a bath or shower to wash off the lotion. Put on clean clothes. All clothes, bedding, and towels used by the infested person two days before treatment should be washed in hot water; dry in a hot dryer. A second treatment of the body with the same lotion may be necessary seven-10 days later. Pregnant women and children are often treated with milder scabies medications.
Anyone who is diagnosed with scabies, as well as his or her sexual partners and persons who have close, prolonged contact to the infested person should also be treated. If your health care provider has instructed family members to be treated, everyone should receive treatment at the same time to prevent reinfestation.
How soon after treatment will I feel better?
Itching may continue for two-three weeks, and does not mean that you are still infested. Your health care provider my prescribe additional medication to relieve itching if it is severe. No new burrows or rashes should appear 24-48 hours after effective treatment.
Related resources from HealthGate:
Centers for Disease Control, August 1999
Last reviewed August 1999 by
Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.
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