Scabies

What is Scabies?

Scabies is an infestation of the skin caused by the microscopic mite Sarcoptes scabiei. Infestation is common, found worldwide, and affects people of all races and social classes. Scabies is contagious, which means it spreads rapidly under crowded conditions where there is frequent skin-to-skin contact between people, such as in hospitals, institutions, child-care facilities, and nursing homes.

How Do People Get Scabies

By direct, prolonged, skin-to-skin contact with a person already infested with scabies. Contact generally 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.

Signs and Symptoms of Scabies Infestation

• Pimple-like irritations, burrows or rash of the skin, especially the webbing between the fingers and/or the skin folds on the wrist, elbow, or knee and/or 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.

How Soon After Infestation Will Symptoms Begin?

For a person who has never been infested with scabies, symptoms may take 4 to 6 weeks to begin. For a person who has had scabies before, symptoms appear within several days.

Who's at Risk for Severe Infestation?

People with weakened immune systems and the elderly are at risk for a more severe form of scabies, called Norwegian or crusted scabies. Scabies is spread more easily by persons who have Norwegian, or crusted, scabies than by persons with other types of scabies.

How Long Will Mites Live?

Once away from the human body, mites usually do not survive more than 48 to 72 hours. When living on a person, an adult female mite can live up to a month.

Do Pets Spread Scabies?

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.

Diagnosis of Scabies Infestation

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 (scybala) to confirm the diagnosis. Even if a skin scraping or biopsy is taken and returns negative, it is still possible that you may 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. However, persons with Norwegian, or crusted, scabies can be infested with thousands of mites and should be considered highly infectious.

Treatment for Scabies

Several creams or lotions that are available by prescription are FDA-approved to treat scabies. Always follow the directions provided by your physician or the directions on the package label or insert. Apply the medication to a clean body from the neck down to the toes. After leaving the medication on the body for the recommended time, take a bath or shower to wash off the cream or lotion. Put on clean clothes. All clothes, bedding, and towels used by the infested person during the 3 days before treatment should be washed in hot water and dried in a hot dryer. A second treatment of the body with the same cream or lotion may be necessary. Pregnant women and children are often treated with milder scabies medications such as 5% permethrin cream. Some examples of safer medicines used to treat scabies include the following:

• Crotamiton cream and lotion 10% (Eurax) - Rx (prescription)
• Permethrin cream 5%, (Acticin, Elimite) - Rx (prescription)
• Permethrin cream rinse 1% (Nix) - OTC (over-the-counter)

Who Should be Treated for Scabies?

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.

Prognosis - Recovery

Itching may continue for 2 to 3 weeks, and does not mean that you are still infested. Your health care provider may prescribe additional medication to relieve itching if it is severe.

This fact sheet is for information only and is not meant to be used for self-diagnosis or as a substitute for consultation with a health care provider. If you have any questions about the disease described above or think that you may have a parasitic infection, consult a health care provider.

References:
1) Centers for Disease Control and Prevention (CDC) - February 2008 - www.cdc.gov/
2) FDA/Center for Drug Evaluation and Research - March 2003 - www.fda.gov/CDER/