DEAR DOC,

What causes scabies, and how is it treated?

DEAR READER

Scabies is caused by a very small bug called the human itch mite. It gets into the top layer of the skin to live, feed and lay eggs. It burrows under the skin; producing thin lines. When the skin reacts to the bug, an itchy rash develops.

It is very infectious because the mite can travel from person to person or from clothes, beddings or furniture. When the mite is deposited on a surface or clothing, it can survive for three to four days without being on a human. It can affect anybody regardless of income level, race or level of cleanliness

The mites like to burrow in the skin between the fingers, around the nails, at the wrists and elbows and on skin that is usually covered by jewellery or clothing. It can take a few days to several weeks to develop the itchy rash after infection. Itching occurs mostly at night and many people develop a rash. This rash looks like many bumps forming a line. Some people get patches of scaly skin while others develop thick crusts. Scratching a lot can cause sores or wounds to develop, which can then get a bacterial infection.

Scabies should be managed by a skin specialist (dermatologist). It can be diagnosed from examination and also from identifying the mite and/or the eggs from a skin scrapping, under a microscope. Different

medications can be used like five per cent permethrin cream, one per cent crotamiton cream, 25 per cent benzyl benzoate lotion, 5-10 per cent sulphur ointment and one per cent lindane lotion. For most of the medications, you apply the medicine just before going to bed and wash it off in the morning. Take a bath before then massage the medication onto clean dry skin and let it stay for eight to 14 hours after which you wash it off. Apply the medication to all skin from the neck and below, including between the fingers and toes, and under the nails.

Children and the elderly may need to have the medication applied to the face and scalp, but avoid the eyes, nose and lips. The treatment can be repeated after a week. Sometimes oral medication (ivermectin) may be prescribed in addition. Other medications that may be used include anti-histamines or steroids to relieve the itching, antibiotics to clear any additional bacterial infection. Other persons who have been exposed should also be treated even if they do not have the symptoms yet because it is very contagious.

In addition, you need to clean all your clothes, towels and beddings with hot water then dry in the sun or in a dryer. Another option is to put all your clothing and beddings in a plastic bag and tie it tight for a week then clean them. The furniture and carpets also need to be cleaned and/or vacuumed. There is no need to treat pets because the mite cannot spread to animals.