Scabies (say: skay-beez) is an itchy skin condition caused by teeny, tiny mites that dig tunnels underneath the skin's surface. Mites are part of the same family that includes spiders and ticks. Scabies mites have eight legs and a round body and are pretty hard to see. When they're fully grown, each mite is no bigger than the size of the point of a pin.
When you get scabies mites, the female mites dig under the top layer of your skin. There they lay eggs and die after about a month. The eggs hatch, and the new mites grow up and come to the skin's surface. The females mate with the males, then the males die and the females dig back under the skin to lay new eggs. This life cycle takes only 2 to 3 weeks.
Mites are more common in places where there are lots of people, like college dorms, camps, classrooms, and childcare centers. In crowded places like these, people are often in close contact with each other. When people get close enough, mites move from skin to skin. That's how you can get scabies — from someone who already has them.
Sometimes the mites may move onto a person from a towel, clothing, or sheets recently used by someone who has scabies, but this is not common. (Doctors believe mites live about 2 to 3 days when they are not on a human body.)
Exams and Tests
Examination of the skin shows signs of scabies. Tests include an examination under the microscope of skin scrapings taken from a burrow to look for the mites. A skin biopsy can also be done.
- Prescription medicated creams are commonly used to treat scabies infections. The most commonly used cream is permethrin 5%. Other creams include benzyl benzoate, sulfur in petrolatum, and crotamiton. Lindane is rarely used because of its side effects.
- Creams are applied all over the body. The whole family or sexual partners of infected people should be treated, even if they do not have symptoms. Creams are applied as a one-time treatment or they may be repeated in 1 week.
- Wash underwear, towels, and sleepwear in hot water. Vacuum the carpets and upholstered furniture.
- For difficult cases, some doctors may also prescribe medication taken by mouth to kill the scabies mites. Ivermectin is a pill that may be used.
Itching may continue for 2 weeks or more after treatment begins, but it will disappear if you follow your health care provider's treatment plan. You can reduce itching with cool soaks and calamine lotion. Your doctor may also recommend an oral antihistamine.
Intense scratching can cause a secondary skin infection, such as impetigo.
Most cases of scabies can be cured without any long-term problems. A severe case with a lot of scaling or crusting may be a sign that the person has a disease such as HIV.