Scabies

WHAT IS IT?
Scabies is a skin disease that can be spread from person to person.

WHAT CAUSES IT?
Scabies is caused by a small insect or mite known as S. scabiei var. hominis. This mite is about the size of a pinhead and can live only 24 hours at room temperature apart from the human body. It burrows into the outer layer of skin and lays eggs, which hatch in 3-5 days. After hatching, the newly formed mites leave the burrow and move to other skin surfaces and repeat the cycle. Scabies is not caused by being dirty.

IS IT CONTAGIOUS?
Yes. Scabies is highly contagious and is spread by skin-to-skin contact with a person who has the disease. Contaminated articles such as clothing, bed linens and blankets can be the source of infection.

WHAT ARE ITS SYMPTOMS?
The most common symptoms are severe itching and grayish-white lines or tracks that zigzag on the skin surface. Areas of the body most commonly affected are the sides of the fingers, webs between the fingers, wrists, elbows, armpits, buttocks, knees and feet. A person never before infested with scabies may not develop symptoms for a month or more. A previously infested person will develop symptoms within 24 hours. The intense itching, which is most severe at night, is caused by a local allergic reaction to the mite's saliva. Itching is worse at night because this is when the mites feed. There may be signs of skin infection like redness, swelling or pus, caused by scratching around the mite's burrows.

HOW LONG WILL IT LAST?
The mite should be completely eliminated after one course of treatment. Itching may continue after treatment, but should subside gradually over a period of several weeks. It should be noted that excessive use of the treatment medication can cause a skin rash and intensify itching. To prevent complications, follow the medication instructions and recommendations carefully.

WHAT TREATMENT CAN YOUR HEALTH PROVIDER OFFER?
Your health care provider can prescribe medication to destroy the mite and to relieve itching. Permethrin (Elimite) Creme is most commonly used. Another medication, Eurax, is available for use with pregnant women and children under age 3.  An older medication, Kwell (Lindane), is not currently recommended, especially for young children.

WHAT CAN I DO IF I AM INFECTED?

  1. Proper use of the prescribed crème is of utmost importance in eliminating scabies. Before applying the medication, take a warm bath or shower using lots of soap to clean the skin. This will help soften the lesions. Pat dry; allow skin to cool. Then, apply the medication in a thin layer from the scalp downward over the entire skin surface, giving special attention to hands, feet and fingers. All areas of the skin must be covered adequately.  If the face is involved, be careful not to get medication in the eyes, nose or mouth. If the hands are washed, reapply crème to that area. Keep the medication on for 12 hours and then bathe. All family members and sexual contacts should be treated at the same time.

  2. Keep medication in a safe place, out of reach of children. Do not take medication for scabies by mouth.

  3. Wash all clothes, underwear and bedding in hot water and dry in the clothes dryer to eliminate any further spread of the mite. Vacuum carpets and upholstery.

  4. It is not necessary to fumigate the entire house.

FOLLOW UP:
Follow up with your health care provider is not necessary after treatment unless symptoms continue for more than a period of two weeks. Most clinicians will not treat a second time unless a skin scraping reveals a scabies mite under the microscope.

Remember: Seek medical attention if....

Source:
Cecil's Textbook of Medicine 21st ed. (2000)