Epidemics of scabies occur in 30-year cycles. There is a 15-year gap between the end of one epidemic and the beginning of the next; the epidemics usually last about 15 years.1 The current epidemic began in most parts of the world in 19642; it should abate by 1979. In the United States, in both urban and rural areas, scabies has undergone a notable increase only in the past several years.3
These cyclic fluctuations of the incidence of scabies are not yet understood. Poverty, poor hygiene, sexual promiscuity, misdiagnosis, demographic factors, increased travel, and ecological considerations are probably promoting factors.2 However, there is cogent information suggesting that immunologic factors are the most important, with delayed hypersensitivity playing the principal role. The following facts are offered as evidence:
A second infestation with scabies (experimentally induced or spontaneous) produces an accelerated response to fewer mites and with a
Today's Scabies. Arch Dermatol. 1975;111(11):1431–1432. doi:10.1001/archderm.1975.01630230033003
Coronavirus Resource Center
Customize your JAMA Network experience by selecting one or more topics from the list below.