Scabies is an itching reaction to mites that burrow into the skin. The disease often affects areas of skin folds, especially in the groin, fingers, toes, wrists and underarms. Scabies is very contagious, spreading easily from person to person on physical contact, often through an entire household. Although it frequently spreads through sexual contact, it can also be passed by a casual handshake with an infected person. On the other hand, mites can rarely be spread via clothing, bedding, and other shared objects; their survival is brief, and normal laundering destroys them.
Scabies is a skin disorder caused when tiny mites (Sarcoptes scabiei) burrow into the skin and cause an allergic reaction that itches. Female mites, less than 1 mm long, also deposit their eggs in burrows under the topmost skin layer. Larvae hatch after a few days. The infection causes intense itching, probably from an allergic reaction to the mites.
The hallmark of scabies is intense itching, which is usually worse at night. The burrows of the female mites appear as wavy lines up to 1,5 mm long, sometimes with a tiny reddish pimple at one end. The burrows are most common and the itching most intense in the webs between the fingers, on the wrists, at the elbows, in the armpits, around women’s nipples, on men’s genitals (penis and scrotum), along the belt line, and over the lower part of the buttocks. The face is rarely involved, except in small children, who may have lesions appearing as water-filled blisters. Over time, the burrows may become difficult to see as a result of scratching with secondary infection.
When to see a doctor
Call your doctor if you need help getting rid of scabies, or if scratching has led to an infection.
Usually the combination of intense itchiness at night and tiny blisters or grooves where the mites have burrowed is all a doctor needs to make a diagnosis of scabies. However, your doctor can take a scraping from the burrows and look at it under a microscope to confirm the presence of mites.
Every member of the household and all contacts must be treated. It takes one month to start itching after infection has occurred.
Bathing and scrubbing with Tetmosol soap is followed by the application of benzoyl benzoate to the skin from the neck down for three consecutive nights.
The treatment of the itch with a mild topical steroid ointment or cream may be necessary for a few days.
Reviewed by Prof H.F. Jordaan, MBChB, MMed (Derm).