How to Identify Scabies

About the Itchy, Painful Rash

1
The Scabies Mite (Sarcoptes scabiei)

Photos of the Itchy, Painful Rash. CDC / Joe Miller / Reed and Carnich Pharmaceuticals

Scabies is an extremely itchy rash caused when the mite, Sarcoptes scabiei (pictured), burrows itself beneath the skin. It's estimated that over 300 million cases of scabies occur globally each year.

The scabies mite is extremely small, measuring less than a half millimeter, and is by far too small to be seen with the naked eye.

Scabies occurs when a female mite burrows under the skin and lays anywhere from 10 to 25 eggs. The eggs hatch in approximately three days. The larvae will then move toward the surface of the skin, maturing into adults within 10 to 14 days.

Scabies is spread by direct skin-to-skin contact. Infested bedding or clothing are rarely causes of infection.

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Scabies Rash on the Body

Photos of the Itchy, Painful Rash. CDC

Scabies resembles other types rashes and is commonly misdiagnosed. The rash (pictured) is similar in appearance to dermatitis, psoriasis, hot tub folliculitis, and pityriasis rosea.

In order to make a diagnosis, your doctor would need to scrape a portion of the rash and examine it beneath a microscope. However, in most cases, the evidence of the mite may not be found. The doctor would then likely treat the rash presumptively if other causes cannot be identified.

If the rash doesn't improve, a skin biopsy may be performed to assist with identification. 

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Scabies Rash Between the Fingers

Photos of the Itchy, Painful Rash. CDC

A common place for scabies to develop is between the fingers. The rash (pictured) will typically be red and pimple-like with small lines, known as burrows, connecting them. Since the mite doesn't travel far beneath the skin, the burrows may not be visible.

The rash can cause painful inflammation with accompanying blisters and itching. Scabies is also commonly found on the wrists, in the armpits, around the waist, and in the genital area.

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Scabies Rash on the Hand

Photos of the Itchy, Painful Rash. CDC / Reed and Carnrich Pharmaceuticals

A typical scabies rash is red and bumpy. In severe cases (pictured), the area can become very inflamed with crusted sores. Scabies is typically treated with both oral and topical medication (including permethrin cream and lindane lotion).

Ivermectin, an oral drug used to treat other parasites, is also considered an effective in killing the mites. It is typically given as a single dose oral of 200 μg per kg of body weight. It may be particularly useful in people with severely crusted lesions when topical treatment has failed.

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Scabies Rash on the Leg

Photos of the Itchy, Painful Rash. CDC / Susan Lindsley

Another common place to find scabies is the groin and genital areas (pictured). If left untreated, the rash can spread to the legs. Topical medications can usually kill the mites, but it will take around four weeks for the body to break them down and absorb them. 

During this time, the skin can be very itchy. Oral antihistamines or topical steroids are often prescribed to help relieve itching.

As a precaution, anyone who has come into close contact with a person who has scabies should also be treated. This includes spouses, sexual partners, or anyone who has had prolonged skin-to-skin contact. A quick hug or handshake is not likely to put someone at risk.

Source:

Centers for Disease Control and Prevention (CDC). "Scabies - Resource for Health Professionals." Atlanta, Georgia; updated March 21, 2017.

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