Human scabies is a skin disease caused by an infestation of microscopic mites. The mites burrow into the top layer of skin and lays eggs there which hatch in 21 days. The burrow can look like a pencil mark, and the scabies rash that occurs as a result is an allergic response to the mites.
Who gets scabies?
Scabies occurs all over the world, affecting people of all social classes, income levels and ages. It can spread rapidly in crowded conditions because it is usually contracted from direct skin-to-skin contact with another person infected with scabies. Institutions such as prisons, nursing homes, child care centers or dormitories are common sites of scabies outbreaks. Often, if one member of a family is infected, the whole family becomes infected. It can also be spread by shared clothing or bedding, though this is less common.
What are the symptoms of scabies?
The most common presenting symptom of a scabies infection is intense itching of the skin which is usually worse at night. A rash also usually appears with tiny sores or blisters that can become worse with scratching. Symptoms typically do not show up for 2 to 6 weeks, especially with a first infection. During this time, however, the infected person can still spread scabies to others which is why infection is so rapid and common.
In adults and adolescents, the infection is more commonly seen on the hands, wrists, abdomen and genitals. With young children, it is typically on the head, neck, shoulders, palms and soles of the feet. Infants may have a more widespread infection, with pimple-like outbreaks on their torso. Elderly people or those with compromised immune systems may also develop a severe form of scabies called crusted scabies or Norwegian scabies, characterized by thick crusts over the skin that contain large numbers of mites, sometimes in the millions.
A health care provider can diagnose scabies with a physical examination, skin scrapings to look for mites under a microscope, or a skin biopsy.
How are scabies treated?
There are several home remedies that can ease the symptoms of scabies. Before treatment, wash all underwear, bed linens, sleepwear and towels in hot water followed by hot drying, and vacuum all carpets and upholstered furniture. This should also be done for all household members and sexual contacts. To treat the rash and itching, soak in a cool bath and then apply calamine lotion to the affected areas. An oral antihistamine or short course of topical steroid cream (like Cortaid) may be used.
There are no over-the-counter medications to eliminate scabies. Scabicide lotions or creams, which kill the mites and sometimes also the eggs, are available only with a doctor’s prescription. The lotion or cream is applied all over the body, from the neck to the feet, and left on for a recommended period of time. For hard to treat cases, an oral pill called Ivermectin may also be prescribed. The use of insecticide sprays or fumigators in the house or on the body or clothing is not recommended.