Scabies

As has already been described, scabies is an intensely pruritic and highly contagious infestation of the skin caused by the mite, Sarcoptes scabiei. Although Sarcoptes mites do not transmit a disease, they are the cause of a disease condition (termed scabies) due to the extremely serious infestations that usually develop. As in many countries, there has been a noticeable increase of scabies in the USA and Canada. Scabies is a global problem and a significant source of morbidity in nursing home residents and workers because of its highly contagious nature. It is also a problem in hospitals that care for the elderly, the debilitated, and the immunocompromised. New outbreaks continue to occur, despite efforts in controlling the recurrent epidemics.

Severe infestations may lead to the development of a condition known as Norwegian scabies or crusted scabies. There are a number of differences between Norwegian scabies and typical scabies. One difference is that when Norwegian scabies affects immunocompromised patients, it results in a severe infestation of myriads of mites; in the healthy person the parasite numbers are far smaller (Clark et al., 1992). The clinical manifestations are also usually different to those of typical scabies. Norwegian scabies may present as a generalized dermatitis with widely distributed burrows, extensive scaling and sometimes vesiculation and crusting. Typical scabies usually presents as lesions prominently around finger webs, anterior surfaces of the wrist, elbows, anterior folds and belt line and causes severe itching especially at night.