Medical quality assurance by Dr. Albrecht Nonnenmacher, MD at February 8, 2016

Scabies is a contagious skin condition that is characterized as a sexually transmitted disease (STD). It can be transmitted through any direct or indirect human contact, and people who live or work in environments with denser populations such as nursing homes, hospitals, and daycare centers are at higher risk than the general population.


Definition & Facts

Scabies begins with the burrowing of a mite from the Sarcoptes scabiei species. This troublesome mite has eight legs and is only about .4 millimeters long. The first mite lays its eggs, and it can take the larvae from three to ten days to hatch.

In an individual who has contracted the condition for the first time, it may take from two to six weeks for the symptoms to appear. The initial itching is caused by an allergic reaction to the mite protein. By the time the itching begins, there is already a large amount of adult mites, larvae, and eggs that are living off the human host. If not treated promptly and thoroughly once discovered or diagnosed, a scabies infestation can last for months and even years.

Scabies is treatable. However, the treatment does not grant immunity from further infestations. Subsequent occurrences result in the symptoms manifesting much sooner, usually, within a few days. Dogs, cats, and other pets and animals also get mites. The species of mites that causes scabies, however, is interested in human hosts only. The mite cannot live for more than three days without a human host.

Symptoms & Complaints

The first symptom that appears with scabies is intense itching. The itching is usually worse at night. The next symptom is the blister-like sores and rash. If the infestation was caused by sexual activity, the first place the rash is discovered will most likely be the genitalia. Other areas frequently affected are the knees, buttocks, underarms, waist area, under the breasts, wrists and between the fingers.

In adults, scabies does not usually affect the face, neck, or lips, but these areas may be affected in children. The rash often resembles pimples or blisters in adults, but may appear more like a welt in children or babies. Actual burrows may also be visible. The burrows will be S-shaped and are an indication the mites are moving under the skin. Infants and toddlers may not be able to verbalize their discomfort from the itching, but there may be noticeable welts, and a scabies outbreak may also cause sleep problems.


In young, sexually active adults, the most common way to contract scabies is through sexual intercourse. Multiple sex partners will make it more likely to contract scabies. However, it can also be spread by a simple hug or other prolonged human touching. It is also possible to pick a mite up off of a towel, blanket, sheet, or even furniture that someone who is infected has been using. The mite needs a human host to survive, so contracting it through indirect contact is much less likely.

One is more liable to get scabies if one frequents or works at a highly populated facility, such as a school, hospital, daycare center or nursing home. Those with weakened immune systems are also more likely to contract scabies. The elderly, often have compromised immune systems and often live in group settings. Often an older person will contract a more severe, more highly contagious type of scabies called Norwegian scabies. Norwegian scabies is characterized by a rash that is crusted and appears as having more scales.

Diagnosis & Tests

Once scabies is suspected, an appointment with a doctor should be scheduled immediately to confirm. When making an appointment, the clinic or office should be informed that scabies is a likelihood. Every effort should be implemented to keep the condition from spreading to others. No blood test determines scabies. Instead, the physician will review the symptoms and circumstances to make the diagnosis.

If there is any doubt, some healthcare professionals will also opt to do a scraping. In this procedure, a section of the skin is scraped where the rash is present. A viewing under a microscope should reveal the culprit mite, and its eggs and larvae. In a home or institutional setting where others also have symptoms, it is usually not necessary to do a scraping on additional patients.

There are many other skin conditions that scabies may resemble, such as hives, shingles, eczema, and various insect bites. Most of these other conditions are not contagious.

Treatment & Therapy

Prescription medication is the only method that can kill the mites, eggs, and larvae and ultimately get rid of scabies. Once diagnosed, a doctor will prescribe permethrin. It is the most effective and safest way to treat scabies. Antibiotics may also be prescribed for infected sores, caused by scratching.

Once scabies is known in a household, or even suspected, all linens and towels should be washed and dried at high temperatures. Since scabies tends to be under fingernails and toe nails, everyone in the household should have their nails clipped.

Relief for itching may be found in oral or topical medications including antihistamines. Those who are exposed to a diagnosed individual should also be treated whether or not they have symptoms.

Prevention & Prophylaxis

If a person has scabies, contact with others should be avoided until cured. It is difficult to prevent scabies if there is direct contact with an infected person. General cleanliness and good hygiene can be helpful, however.

For individuals working with residents or patients that are thought to be infected, it is best to wear gloves and gowns. Being aware of symptoms and seeking treatment or advice promptly is the best prevention.

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