What is scabies, and why is diagnosis often delayed?

Updated: Oct 13, 2020
  • Author: Megan Barry, MD; Chief Editor: Dirk M Elston, MD  more...
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Human scabies is an intensely pruritic skin infestation caused by the host-specific mite Sarcoptes scabiei var hominis. A readily treatable infestation, scabies remains common primarily because of diagnostic difficulty, inadequate treatment of patients and their contacts, and improper environmental control measures. Scabies is a great clinical imitator. Its spectrum of cutaneous manifestations and associated symptoms often results in delayed diagnosis. In fact, the term "7-year itch" was first used with reference to persistent, undiagnosed infestations with scabies (see the image below). (See Presentation, Workup, Treatment, and Medication.)

Scabies mite scraped from a burrow (original magni Scabies mite scraped from a burrow (original magnification, 400X).

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