What Is Scabies Rash?

What Causes This Itchy Skin Condition, How It Spreads, and More

Scabies is a very itchy rash that's caused by the mite Sarcoptes scabiei. Scabies rash occurs in both sexes, in people of all ages, and in people of all ethnic groups. In fact, it's estimated that at least 300 million cases of scabies occur worldwide every year.

What Causes Scabies Rash

The mite that causes scabies rash is tiny, often too small to be seen with the naked eye. The female mite burrows under the skin and lays 10 to 25 eggs before she dies.

The eggs hatch three days later and the larvae move to the surface of the skin. The larvae mature into adults in 10 to 14 days.

How It Spreads

Scabies rash is spread by direct skin-to-skin contact. Contact with infested bedding or clothes only rarely causes a new infection.

What It Looks Like and Where It Occurs

The rash that scabies causes can often look similar to other rashes. The rash causes red papules with small lines that are attached (they're called burrows). The mite doesn't usually travel far once it's under the skin, so the burrows may not be visible. These photos will give you a good idea of what a scabies rash can look like.

A scabies rash typically occurs on the wrists, in between fingers, in the armpits, around the waist, and in the genital area. The rash causes intense inflammation in the skin with blisters, redness, and itching. 

Scabies Rash Diagnosis

Scabies is usually diagnosed when the appearance and location of the rash fit the descriptions above.

A rash is more likely to be scabies if a family member has a similar rash. There are no good tests that can diagnose scabies. Some textbooks suggest scraping off a small portion of the rash and looking at it under a microscope for mites, but the mite is rarely found with this test.

Medications That Kill the Mites

The following are treatment options that can help get rid of scabies rash.

  • Permethrin 5% cream: Apply it liberally from the top of the neck to the soles of the feet at bedtime and rinse it off in the morning. Permethrin is the safest treatment for pregnant women.
  • Lindane 1% lotion: Apply a thin layer of it from the top of the neck to the soles of the feet at bedtime and rinse it off in the morning. Lindane should not be used by pregnant women.
  • Ivermectin: This is an oral medication that's used to treat other parasites. The dose used is based on the weight of the person who is taking the medicine and the drug is taken in two doses, two weeks apart. It is currently not approved by the FDA for the treatment of scabies, but there are studies that show that it is effective.

Treatment of Itching

Using the above medications kills the mites, but they are still present in the skin until the body breaks them down and absorbs them. This process can take about four weeks and it is common for the scabies rash to be very itchy for the entire month. Topical steroids that are applied to particularly itchy spots and oral antihistamines like Benadryl may help relieve any itching.

Treatment for Loved Ones Who Have Scabies Rash

People who have close contact with someone who has been diagnosed with scabies also should be treated.

"Close contact" includes sexual partners and anyone who has had prolonged, skin-to-skin contact with someone with scabies rash. Often, entire households are treated even if only one person has symptoms. If your healthcare provider recommends treating your whole family, all family members should receive treatment at the same time. Giving someone a quick hug or a handshake does not usually put you at risk. 

Clothing and Bedding

All clothes, bedding, and towels used by the person who has scabies rash should be washed in hot water and dried in a hot dryer.

Sources:

"Scabies Fact Sheet." CDC. 10 Feb 2005. 19 Aug 2007.

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