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Scabies: Epidemiology, clinical features, and diagnosis

Beth G Goldstein, MD
Adam O Goldstein, MD, MPH
Section Editors
Robert P Dellavalle, MD, PhD, MSPH
Moise L Levy, MD
Ted Rosen, MD
Deputy Editor
Abena O Ofori, MD


Scabies is an infestation of the skin by the mite Sarcoptes scabiei. Classic scabies typically manifests as an intensely pruritic eruption with a characteristic distribution. The sides and webs of the fingers, wrists, axillae, areolae, and genitalia are among the common sites of involvement. Crusted scabies, a less common variant that primarily occurs in the setting of reduced cellular immunity and is associated with a heavy mite burden, is characterized by thick scale, crusts, and fissures. The diagnosis of scabies is confirmed through the detection of scabies mites, eggs, or feces with microscopic examination.

The clinical features and diagnosis of scabies will be reviewed here. The management of scabies is discussed separately. (See "Scabies: Management".)


Scabies is a relatively common infestation that can affect individuals of any age and socioeconomic status. The worldwide prevalence is estimated to be 100 million people, with wide variation in prevalence among individual geographic regions [1,2]. A systematic review of population-based studies from various regions of the world (excluding North America) found prevalence estimates ranging from 0.2 to 71 percent, with the highest prevalences in the Pacific region and Latin America [3]. Scabies is particularly common in resource-limited regions.

Crowded conditions increase risk for scabies infestation [4]. Epidemics can occur in institutional settings, such as long-term care facilities and prisons [5].


S. scabiei var. hominis is a whitish-brown, eight-legged mite (picture 1A). Female mites are larger than male mites and measure approximately 0.4 x 0.3 mm [4]. After mating, female mites burrow into the epidermis, a process facilitated by secretion of proteolytic enzymes that cause keratinocyte damage [6]. Female mites continue to extend the burrow and lay two to three eggs per day before dying after four to six weeks [4]. Larvae hatch in three to four days and molt three times within the burrow to reach adulthood.

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Literature review current through: Sep 2017. | This topic last updated: Sep 27, 2017.
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