Management of Scabies

Gentiane Monsel, MD; Olivier Chosidow, MD, PhD

Disclosures

Skin Therapy Letter. 2012;17(3) 

In This Article

Abstract and Introduction

Abstract

Scabies is a common contagious parasitic dermatosis. Transmission of the mite Sarcoptes scabiei var hominis generally occurs by skin-to-skin contact, but with crusted scabies it may also occur through fomites, such as infected clothing or bedding. Diagnosis is usually clinical. A 2010 updated Cochrane review concluded that management of scabies is based on topical scabicides, mainly 5% permethrin. However, oral ivermectin, although not licensed in many countries, may be useful, particularly for patients who cannot tolerate or comply with topical therapy and in institutional scabies epidemics. Patients should also receive detailed information about the infestation to limit further spreading. Cases resulting from close physical or sexual contact, even without symptoms, should be systematically treated. Hygienic measures should be taken after treatment is completed. Patients should be followed to confirm cure, including resolution of itching, which may take up to 4 weeks or longer.

Introduction

Scabies is a common parasitic infection caused by the mite Sarcoptes scabiei var hominis, arthropod of the order Acarina. The worldwide prevalence has been estimated at about 300 million cases annually, although this may be an overestimate.[1] In general, transmission occurs by direct skin-to-skin contact. In crusted scabies, transmission may also occur through infected clothing or bedding. Skin eruption with classical scabies is attributable to both the infestation and a hypersensitivity reaction to the mite. Moreover, because the eruption is usually itchy, prurigo and superinfection are common.

The main symptom is pruritus that typically worsens at night, and it is often associated with itching experienced by other family members in the household or amongst people in close physical contact with an infested individual. The lesions are commonly located in the finger webs, on the flexor surfaces of the wrists, on the elbows, in the axillae, and on the buttocks and genitalia. The elementary lesions are papules, burrows, and nodules. In crusted scabies, clinical signs include hyperkeratotic plaques, papules and nodules, particularly on the palms of the hands and the soles of the feet, although areas such as the axillae, buttocks, scalp, and genitalia in men, and breasts in women may also be affected.[1]

The definitive diagnosis relies on the identification of mites. Multiple superficial skin samples should be obtained from characteristic lesions by scraping with a scalpel. The specimens are examined under a microscope, looking for mites, eggs, empty eggs, and scybala. Failure to find a mite is common and does not rule out scabies.[1] New methods such as dermoscopy or adhesive tape test may increase the sensitivity of skin scraping tests and limit false-negative results.[2,3] However, comparing the accuracy of different tests for diagnosing scabies remains elusive without a criterion standard.[4]

Scabies may be endemic in indigenous communities with a high rate of superinfection, which implies the need for specific management. Here, we describe the management of scabies in Western countries.

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