Tue, Oct 07, 2008 - Page 16 News List

[ HEALTH ] Scabies, it’s enough to make your skin crawl

Affecting more than 300 million people worldwide each year, scabies, an infestation of tiny mites, is frequently misdiagnosed

By Jane E. Brody  /  NY TIMES NEWS SERVICE, NEW YORK

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Most people expect to return from vacation with fond memories of a relaxing or exciting time and perhaps photos to document it. That wasn’t exactly the case for one 25-year-old man who took a trip to a Brazilian beach. Five weeks after returning to his home in Spain, he began to itch. He itched everywhere, intensely, and especially at night, which made sleep almost impossible.

After two months of this torment, with pimples and the sores from scratching them on his abdomen, buttocks and genitals, he sought help from a dermatologist. The diagnosis was scabies, an infestation of tiny mites he had most likely contracted from a sexual encounter during his vacation.

In describing this case in the July issue of The Cleveland Clinic Journal of Medicine, Sergio Vano-Galvan and Paula Moreno-Martin of Madrid called medical attention to a worldwide public health problem that each year affects more than 300 million people.

Scabies is frequently misdiagnosed and mistreated, partly because most physicians are unfamiliar with it and partly because its symptoms mimic so many other skin diseases.

A correct diagnosis is further complicated by the fact that symptoms can often appear six to eight weeks after a person becomes infested with the microscopic arthropod, making it seem as if the problem came from nowhere. But unlike other skin diseases, scabies is usually accompanied by a tell-tale sign: one or more burrows in the skin where female mites lay their eggs.

Scabies is easily cured, but only if patients and their close contacts conscientiously follow directions for medical treatment and environmental cleanup. However, even after a person is rid of the mites and their eggs, itching can persist for up to four weeks.

THE CULPRIT

The scabies mite, Sarcoptes scabiei, can afflict a number of animals. In dogs and sheep, the infestation is commonly called mange. Each species of animal has a specific variant of the mite, which cannot reproduce in other hosts. If your dog gets mange, as mine once did, you may be itchy for a while if the mites get into your skin, but the condition will cure itself when the adult mites die.

It’s not so easy if you acquire the human scabies mite. At 0.4mm in length, the mite is barely visible to the naked eye. But just 10 adult females breeding in a person’s skin are enough to cause bodywide torment, as they defecate and lay eggs that then hatch into larvae and develop into more adult mites. The itching is due to an allergic reaction to the mite, its excrement and burrows, though an antihistamine alone is rarely enough to squelch the desire to scratch.

Scratching, however, can cause sores that become infected with bacteria like Staphylococcus or Streptococcus, prompting a diagnosis of impetigo and perhaps missing the underlying cause.

Scabies spreads most often through direct, prolonged skin-to-skin contact, like that between sexual partners and members of a household. As the Centers for Disease Control and Prevention put it in a fact sheet on scabies, “A quick handshake or hug will usually not spread infestation.” But the mite can also be acquired from contaminated bedding, clothing or towels recently used by a person with scabies. Although an adult female mite can live on a person for up to a month, the mite rarely survives more than three days apart from a living body.

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