Scabies

This is probably the itchiest disease you can get. Even its name comes from a Latin word meaning “to scratch,” and you’re likely to be doing lots of that.

Scabies is a condition caused by microscopic parasitic mites (or bugs) that burrow under your skin and produce a red rash, along with severe itching. The disease is often transmitted through sexual contact, but you can get it from any close skin-to-skin contact with someone who has scabies, even by holding hands. Less commonly, it’s also passed along by contaminated clothes, bedding, or towels.

Some people feel sheepish about getting scabies because they associate it with poor hygiene. The truth is that no one should feel embarrassed about it. You can get scabies even if you’re scrupulously clean; all you have to do, in some cases, is touch someone who’s infected. The bug, known as Sarcoptes scabiei, is common throughout all socioeconomic classes (including the wealthy) in the United States. Scabies is extremely contagious; epidemics often break out in daycare centers and nursing homes.

You develop a severely itchy rash with red patches, usually between the fingers, around the wrists, and on the elbows, armpits, navel, nipples, lower abdomen, and genitals. You may also itch under your rings, bracelet, and watchband, where scabies mites like to hide. Your face should be relatively unscathed, since scabies mites rarely venture above the neck.

The itching is usually most intense after a hot bath or at night and may keep you awake. You may also see curvy white or razor-thin red lines where the mites have burrowed under your skin (these are visible in only about 25 percent of people with scabies). Nasty-looking scabs might also form over the areas you’ve scratched, and a bacterial infection may develop.

If this is your first bout of scabies, four to six weeks may pass from the time the bugs latch onto you until the time you begin to itch. If you’ve had scabies before, the wait will last only one to three days.

There’s a slight chance that you might develop crusted or Norwegian scabies, a more severe and highly infectious form of the illness. If so, your hands, feet, and trunk will be scaly and crusted, with innumerable live mites hiding under the crusts. Often there will be little or no itching. The condition is difficult to treat, because the medications used to kill the mites may not be able to get through your thickened skin. Crusted scabies is most often found among the elderly and among people with AIDS.

Why does scabies itch so much?

It’s the unwanted guests setting up housekeeping in your body. Female scabies mites burrow under your skin, where they lay eggs and also deposit feces. The eggs and feces trigger an allergic reaction in your skin, which is what causes the nearly intolerable itching.

How can I be sure it’s scabies?

If your doctor isn’t certain you have scabies, she may do a painless test that involves scraping off a small piece of skin and looking at it under a microscope. Scabies mites or their eggs will show up under magnification.

Scabies is relatively easy to get rid of. Your doctor will prescribe a topical insecticide, which must be spread over every square inch of your body from the neck down. (You may need some help reaching some areas.) The recommended treatment is a 5 percent permethrin cream, according to guidelines from the Centers for Disease Control and Prevention (CDC). Don’t forget to put the cream between your toes and fingers, under your arms, in your navel, and on your genitals. Even areas that don’t seem to be infected must be treated, so don’t skip them. The cream stays on for eight to 14 hours (overnight is most convenient), and then you wash it off.

All other members of the household, as well as sexual partners and babysitters, will probably need to be treated as well, even if they show no symptoms. It’s best if everyone gets treated at the same time, so one contaminated person doesn’t reinfect everybody else. (Doctors call this a “ping-pong infection.”)

You’ll need to vacuum the floors (throwing the bag in the trash), then wash all clothing, towels, and bedding in water over 130 degrees Farenheit and dry it in a dryer. (Be sure to turn the washing machine thermostat back down to 120 degrees after you’ve finished to avoid accidental scaldings.) The best plan is to apply the cream at night, do your wash the first thing the next morning, shower, and then transfer laundry to the dryer. If you have items that can’t be washed, such as stuffed animals or other toys, seal them in a plastic bag for at least three days. Scabies mites can’t live for more than three to four days without a human host.

Since the itching may continue for as long as three weeks after the mites are gone, your doctor might prescribe a cortisone cream to relieve it. If the symptoms are still present after a week, he or she may also have you use the insecticide cream a second time. The rash may take between two and six weeks to clear up.

No matter how awful the itching is, don’t try such bizarre home remedies as dousing yourself with kerosene or scrubbing your skin with lye; they’re extremely dangerous.

As an alternative to permethrin, doctors sometimes prescribe lindane (1 percent) lotion or cream, but resistance to it has been reported in different parts of the States; in certain cases, it has also been associated with seizures and aplastic anemia. According to the CDC, lindane should not be used unless other treatments don’t work. The CDC also says that lindane shouldn’t be used immediately after taking a bath or shower, or by young children, women who are pregnant or nursing, or people who have extensive dermatitis (skin irritation).

How long will I be contagious?

You can return to work or school after one treatment with the cream. Be aware that you may continue to feel itching for some days after the mites are dead.

Government experts and the medical community consider permethrin cream safe for everyone, including infants as young as 2-months-old. Some of the medicines previously used to treat scabies (such as lindane cream) were more controversial.

How can I keep from getting scabies?

The only way to avoid it is to avoid contact with anyone who might have it. That can be difficult, especially if you work in a hospital, daycare center, or another crowded environment where the disease often breaks out. Good hygiene isn’t a guarantee that you’ll be able to avoid scabies, but it can help: People who bathe or shower regularly, wash their clothes after one or two wearings, and avoid sharing hats, combs, and even headphones may be less likely to make the acquaintance of the horrid mites. It’s important to practice safer sex, too.

American Social Health Association Facts & Answers About STDs

Centers for Disease Control STD and AIDS hotlines (24 hours a day/7 days a week) 1-800-227-8922 or 1-800-342-2437

Centers for Disease Control. Scabies Medications. November 2008. http://www.cdc.gov/scabies/hcp/meds.html

Centers for Disease Control and Prevention, Scabies Frequently Asked Questions

American Academy of Dermatology. Scabies: What to Look For.

American Social Health Association. Information to Live By: Scabies.