Introduction

Scabies is an intensely itchy dermatosis caused by the mite Sarcoptes scabiei. A patient with ordinary scabies may have an average of 12 mites; however, those with crusted scabies may have thousands of mites. The infestation occurs at all ages, but particularly in children. It is a common public health problem in poor communities and is widespread in many underdeveloped countries.

How is it spread?

Scabies is highly contagious, and person to person spread occurs via direct contact with the skin. Transfer from clothes and bedding occurs rarely and only if contaminated by infested people immediately beforehand.1

Infestation occurs when the pregnant female mite burrows into the skin and lays eggs. After two or three days, the larvae emerge and dig new burrows. They mature, mate, and repeat this cycle every two weeks.

How do I diagnose it?

A history of itching in several family members over the same period is almost pathognomonic. However, lack of a history of itching in family members does not exclude scabies. It can be notoriously difficult to get family members to admit to a history of possible scabies, and some people with scabies genuinely seem not to itch.

If left untreated, scabies can continue for many months. It is important to remember that recurrence of symptoms after attempted treatment does not exclude the diagnosis of scabies because patients may not have treated themselves correctly or may have been reinfested by an untreated contact.