Scabies: A Review of Diagnosis and Management Based on Mite Biology

Alexandra K. Golant; Jacob O. Levitt

doi:10.1542/pir.33-1-e1

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Alexandra K. Golant, MD*
Jacob O. Levitt, MD*

^*Department of Dermatology, The Mount Sinai Medical Center, New York, NY

Author Disclosure
At the time he wrote this article, Dr Levitt was the Vice-President of Taro Pharmaceuticals, USA, Inc, which manufactures a malathion product, and a stockholder. Dr Golant has no financial interests relevant to this article. The article does include discussion of unapproved therapeutic agents.

Abbreviations:

BIT:: burrow ink test
Ig:: immunoglobulin
KOH:: potassium hydroxide

Objectives

After completing this article, readers should be able to:

Understand the biology and life cycle of the mite Sarcoptes scabiei var hominis.
Know how to diagnose a scabies infestation.
Recognize the three basic clinical presentations of scabies: classic, crusted and nodular.
Understand how scabies is transmitted and the risk of infestation to contacts.
Know the principles of managing scabies, including pharmacologic treatment and the prevention of recurrence.

Introduction

Scabies is a parasitosis caused by the mite Sarcoptes scabiei var hominis, with crusted scabies being more contagious than classic scabies because of a larger mite burden. Scabies is found primarily in poor and overcrowded conditions but can affect individuals of all ages and socioeconomic status without regard to level of hygiene. The predominant disease manifestations are mediated through inflammatory and hypersensitivity reactions to mites and mite products. (1) Hallmarks of infestation include intense itching, papular rash, and emotional disturbance from the concept of arthropod infestation. Complications of bacterial infection are a cause of significant morbidity in developed but especially in less developed countries. Effective scabies control requires treatment of affected patients, their close contacts, and environmental fomites. Control is difficult to achieve because of delayed or missed diagnosis, improper application of medication, inadequate treatment, or poor compliance. Treatment with most scabicidal medications calls for treating with an initial dose and re-treating 7 days later; however, the biological basis for when optimally to re-treat has never been documented.