Reference work entry
Scabies is a human infection of the skin with the mite Sarcoptes scabiei or a transitory infection with similar species from animals where they produce mange (Figs. 1 and 2). The entire life cycle of the mite takes place in the keratinaceous layer of the epidermis which often undergoes hyperplasia with marked hyperkeratosis around papules or burrows created by the mites, often on the hands, feet, genitalia, or axilla. Adults create burrows in the keratinaceous layer where they live and lay eggs, which give rise to larvae, nymphs, and new adults ( Pathology, Fig. 30b). Metabolic products of the mites give rise to inflammation with lymphocytes and eosinophils in the dermis. In the absence of a thickened stratum corneum, mites elicit more inflammation, more itching, and often ulcers from scratching, sometimes with secondary bacterial infection. Glomerulonephritis may result from secondary streptococcal infection of the lesions.
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