Scabies: Epidemiology, clinical features, and diagnosis
- Beth G Goldstein, MD
Beth G Goldstein, MD
- Adjunct Clinical Assistant Professor
- Department of Dermatology
- University of North Carolina at Chapel Hill
- Adam O Goldstein, MD, MPH
Adam O Goldstein, MD, MPH
- Department of Family Medicine
- University of North Carolina at Chapel Hill
- Section Editors
- Robert P Dellavalle, MD, PhD, MSPH
Robert P Dellavalle, MD, PhD, MSPH
- Section Editor — General Dermatology
- Professor of Dermatology and Public Health
- University of Colorado School of Medicine
- Colorado School of Public Health
- Chief, Dermatology Service
- US Department of Veterans Affairs
- Eastern Colorado Health Care System
- Moise L Levy, MD
Moise L Levy, MD
- Section Editor — Pediatric Dermatology
- Professor of Pediatrics and Medicine (Dermatology)
- Dell Medical School, University of Texas, Austin
- Clinical Professor of Dermatology and Pediatrics
- Baylor College of Medicine
- Ted Rosen, MD
Ted Rosen, MD
- Section Editor — Infections and Infestations
- Professor, Department of Dermatology
- Baylor College of Medicine
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 . Scabies is particularly common in resource-limited regions.
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 . After mating, female mites burrow into the epidermis, a process facilitated by secretion of proteolytic enzymes that cause keratinocyte damage . Female mites continue to extend the burrow and lay two to three eggs per day before dying after four to six weeks . Larvae hatch in three to four days and molt three times within the burrow to reach adulthood.To continue reading this article, you must log in with your personal, hospital, or group practice subscription. For more information on subscription options, click below on the option that best describes you:
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- LIFE CYCLE
- CLINICAL MANIFESTATIONS
- Classic scabies
- Crusted scabies
- History and physical examination
- Examination for mites
- - Scabies preparation
- - Dermoscopy
- DIFFERENTIAL DIAGNOSIS
- INFORMATION FOR PATIENTS
- SOCIETY GUIDELINE LINKS
- SUMMARY AND RECOMMENDATIONS