Scabies is an infestation of the skin by a mite called Sarcoptes scabiei. It causes intense itching and can be spread from one person to another through close skin-to-skin contact. Fortunately, effective treatments for scabies are available.
What causes scabies?
The mites that cause scabies are tiny parasites, smaller than a pinhead. They are usually picked up by direct skin-to-skin contact with someone who already has scabies, and only very rarely from objects such as clothing or bedding. Pets do not spread them. People with scabies have an average of about a dozen adult mites on their skin; a few carry many more. Being dirty does not cause scabies. Rarely, a variant of scabies called crusted scabies can occur in patients who are immunosuppressed or who are elderly and unwell. There are thousands of scabies mites on the skin in this variant and it is highly contagious.
Is scabies hereditary?
No, but it is common for several members of a family to have it at the same time.
Scabies is spread through personal contact
Scabies is usually spread from person to person by close, prolonged physical contact such as touching a person who has scabies or holding hands. It can also be spread during sexual contact. Clothes, towels, or bed sheets can spread the scabies mite if the items were recently in contact with a person who has scabies. The mites will die within 48 hours if they are away from the human body. Scabies can spread quickly in crowded situations where there is frequent skin-to-skin contact (such as hospitals, nursing homes, and child care centers). People cannot catch scabies from animals.
The primary symptom of scabies is widespread itching, which may be severe and is usually worse at night. Scabies also causes visible lesions (reddish bumps or blisters) on the skin; however, these are often very small and can be difficult to see. These bumps or blisters if you scratch frequently.
A person may also notice a “burrow” or tunnel sign, a thin, visible line in the skin that extends from 2 to 15 millimeters (0.08 to 0.6 inches). Although not everyone with scabies has visible burrows, the presence of such marks strongly suggests scabies. The following parts of the body are more likely than others to be affected by scabies
●The fingers and webbing between the fingers
●The skin folds around the wrists, elbows, and knees
●The area surrounding the nipples (particularly in women)
●The male genitalia (penis and scrotum)
●The lower buttocks and upper thighs
●The sides and bottoms of the feet
The back is usually not affected, nor is the head. Scabies lesions can become more irritated and inflamed with scratching, which may lead to infection.
What does scabies look like?
The rash of scabies is a mixture of scratch marks and red scaly areas; later it can become infected and develop small pus spots. A widespread rash similar to eczema (dermatitis) is very common. This itchy rash covers much of the skin but the mites are found mainly in the web spaces of the fingers and on the palms of the hands, the wrists, ankles and soles of the feet.
The scabies mites burrow into the skin in these areas to lay their eggs. Burrows appear as small greyish lines on the skin. Adult mites are tiny, only about 0.4 mm long, appearing through a lens as a tiny dark dot lying at the end of a burrow. In crusted scabies the rash may mimic psoriasis and may not cause intense itching.
Scabies is treatable
Creams or lotions that kill the mite (such as 5% permethrin, lindane, and crotamiton) can be applied to the skin. Follow your doctor’s instructions for treatment. Itching may continue for up to 1 to 2 weeks after treatment; it does not mean that the treatment did not work or that you have scabies again. Sometimes, a second course of treatment is necessary. Clothing and bed linens worn or used in the 48 hours before treatment should be washed and dried on hot cycles or professionally dry cleaned. There is no need for treatment of rugs or fumigation of the house, other than vacuuming and general cleanliness.
Scabies can be prevented
● Infested persons should be excluded from school or child care until after starting treatment, usually the overnight.
● No one should share clothing, bedding, or other personal articles with an infested person.
● Clothing that cannot be laundered or dry cleaned should be stored for several days to avoid re-infestation.
● All household members and close contacts of a person with scabies should be treated at the same time as the person with scabies.