Scabies

Scabies is an infestation of the skin by a mite too small to see, Sarcoptes scabiei. The female mite burrows into the upper layer of skin and lays her eggs there. The body reacts to the mites and their droppings, and that reaction causes the itch and the rash.

It occurs everywhere and is commonest in hot countries and wherever people live close together. It is not dangerous for most people, but it is very itchy, it spreads readily within a household, and it does not clear without treatment.

The main symptom is intense itching that is usually worse at night and disturbs sleep. A rash of small bumps and spots follows, and scratch marks are often the most obvious sign.

• Between the fingers, on the wrists and the inner elbows
• Around the waist, the armpits, the buttocks and the navel
• On the genitals, and around the nipples
• In babies and older people, also on the head, neck, palms and soles
• Fine wavy lines where a mite has burrowed under the skin

After a first infestation, symptoms can take four to eight weeks to appear. If someone has had scabies before, the itch starts much sooner. A severe form, crusted scabies, causes thick flaky crusts, may itch little, and carries very large numbers of mites, so it spreads very easily.

See a doctor within a few days for itching that is worse at night with a bumpy rash, if others at home are itching too, for thick crusted patches, for a child under two years old, or if itching is still there two to four weeks after treatment.

Scabies is caused by the human itch mite. It passes from person to person through direct, prolonged skin-to-skin contact, such as sharing a bed, holding a child, or sexual contact. A brief handshake is unlikely to pass it on.

Less often it spreads through clothing, towels or bedding used recently by an infested person. Crusted scabies spreads much more easily, including by brief contact and by contaminated items, because of the very large number of mites on the skin.

• Living in a crowded home, hostel or care home
• Sharing a bed or close physical contact with someone who is itching
• Young children, and older people who need close personal care
• Working in childcare, nursing homes or other close-contact settings
• New sexual partners
• A weakened immune system, which raises the risk of crusted scabies

Scratching breaks the skin and lets bacteria in. The commonest complication is impetigo, a crusted bacterial skin infection, which needs antibiotic treatment. A deeper infection can spread and, rarely, reach the bloodstream.

Some of the bacteria that infect scratched skin can also lead to kidney inflammation, and are linked with rheumatic heart disease. Broken sleep from weeks of itching affects school, work and mood. Crusted scabies is serious and needs specialist care.

• Treat everyone in the household and any sexual partner on the same day
• Avoid close skin contact for 24 hours after treatment starts
• Wash bedding, clothes and towels used in the last few days at 60 degrees Celsius or hotter, and dry them thoroughly
• Seal items that cannot be washed in a plastic bag for several days
• Do not share clothes, towels or bedding while treatment is going on
• Tell close contacts, so they can be treated before they pass it on
• Keep nails short to reduce damage from scratching

A doctor usually diagnoses scabies from the pattern of itching, the sites of the rash, the burrows, and the fact that others in the house are itching too.

To confirm it, a small scraping of skin can be examined under a microscope to look for a mite, its eggs or its droppings. Not finding one does not rule scabies out, so treatment is often started on the history and appearance alone.

Scabies is treated with a medicine that kills the mites, as a cream or lotion applied to the skin, or sometimes as tablets. These are prescribed or supplied by a pharmacist. No untested home remedy clears the infestation.

The cream or lotion is applied over the whole body, including between the fingers and toes and under the nails, and for young children and older people the scalp and face as well. It is left on for the stated number of hours and then washed off, and the whole treatment is repeated after about a week, because the medicines do not kill the eggs.

Everyone in the household and any sexual partner is treated on the same day, symptoms or not. Bedding, clothing and towels are washed hot on the first day. Itching may continue for a few weeks; a doctor may suggest something to ease it, and antibiotics if the skin has become infected. Crusted scabies needs specialist treatment, often with both tablets and creams.