How to Know if That Rash Is Scabies

Sometimes an itch is just a temporary annoyance, but if that itch persists, begins to show as a rash, or gets worse at night, you may have scabies.

This skin condition that causes itching and, typically, raised red spots starts when human itch mites (called Sarcoptes scabiei) burrow under your skin and lay eggs there. In most healthy adults, just 10 to 15 mites can cause scabies.

According to the American Academy of Dermatology, immunocompromised or elderly patients are at greater risk for contracting crusted, or Norwegian, scabies — a form of scabies involving an extreme infestation of thousands of mites — and as a result can become highly contagious.

Scabies can spread quickly in nursing homes, dormitories, camps, and other places where people are crowded together and come in contact with each other. Of course, it can also spread among families and cohabitants once one person brings it into the house. Scabies spreads from person to person, but you don’t get it from pets. Your doctor can help you distinguish scabies from other causes of a rash.

Scabies spreads through contact, not because of a lack of personal hygiene. But doctors say it can be difficult to inform people they have mites because of the stigma associated with them.

“I think a common misconception is that only people who are filthy or dirty get scabies,” says Robin P. Gehris, MD, the chief of pediatric dermatology at the Children's Hospital of Pittsburgh, part of the University of Pittsburgh Medical Center. “Even royalty, with the right exposure, can get scabies.”

“It doesn’t present [show up] with symptoms immediately,” says Dr. Gehris. “Unless you’ve had it before, it takes about a month between when the mites set up shop and when it shows up in your skin.”

What It Feels Like to Have Scabies: Signs and Symptoms

Scabies typically starts with itching and a pimple-like rash, often in areas around your wrists, finger webs, elbows, armpits, waist, knees, ankles, or groin. Sex is a common route of infection.

One of scabies’ more distinctive effects happens when it worsens.

“It keeps people up at night — they don’t sleep well, and mentally they get very anxious,” says Adam Goldstein, MD, MPH, a professor of family medicine at the University of North Carolina (UNC) School of Medicine in Chapel Hill.

If you think you may have scabies, a trip to your primary care doctor or dermatologist will often resolve the mystery. Under a microscope, a slide with a sample from the irritated area will typically show the mites.

Solve the Problem: Scabies Treatment That Works

“Primary care doctors can absolutely treat it, but sometimes it doesn’t present as straightforward, so you might end up seeing a specialist,” says Beth Goldstein, MD, a dermatologist in private practice in Chapel Hill and an adjunct at UNC. Dr. Beth Goldstein and Adam Goldstein, MD, MPH, have coauthored guides for physicians on recognizing and treating scabies.

“I have had people with absolutely no rash who are just itchy,” says Amy Kassouf, MD, a dermatologist at the Cleveland Clinic in Ohio. “It’s really an allergic reaction to the mite that makes you so itchy. Not everyone shows that as a rash.”

While the itching may be unpleasant, treating it is usually fairly straightforward, as long as you follow the recommended steps. When you go to your doctor for treatment, they may recommend an antihistamine and permethrin, which is applied to the skin to kill the mites. Usually, you apply it at bedtime.

“People can itch even if treated, but they will feel progressively better,” says Beth Goldstein.

Two applications of permethrin are recommended. Five to seven days after the first treatment, you’ll need a second treatment with permethrin to kill off mites that have hatched in the interim. This second step is important to prevent having to start the treatment cycle again.

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Getting the Entire Household Scabies Free

In families or households where one person has scabies, you’ll need to be proactive about treating everyone for scabies — even if they don’t have symptoms. That goes for babysitters or frequent visitors like grandparents, too.

“When one family member in a household gets diagnosed, in order to effectively treat that household, you have to treat everyone who lives there — not just the people who have rashes or are itchy,” says Gehris.

“If you don’t successfully treat it, it’s going to continue,” says Dr. Adam Goldstein.

That’s especially important for families to keep in mind. In addition to treating the person with scabies, the bedding, clothes, and towels need to be washed in hot water and dried on a hot setting, or dry-cleaned to rid them of the parasites.

Items that cannot be washed should be sealed in a plastic bag for 72 hours or more to kill the mites. This effectively decontaminates things like toys and other objects handled by the infected person or household members, in order to keep the mites from continuing to spread, notes the Centers for Disease Control and Prevention.

Additional reporting by Deborah Shapiro.