How is scabies characterized clinically? -
| | Fig. 34.3 Scabies. A, Characteristic linear burrow. B, Nodular scabies most commonly presents in male genitalia as markedly pruritic papules. The lesion is almost diagnostic. (Courtesy of the Fitzsimons Army Medical Center teaching files.) | There is an insidious onset of red to flesh-colored, pruritic papules. - The itch is almost always worse at night.
- Secondary cases are almost always present—person-to-person transmission.
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| | Fig. 34.4 Biopsy of scabies demonstrating mite in burrow. (Courtesy of James E. Fitzpatrick, MD.) | The rash has a distinctive distribution involving the interdigital webs of the hands, the volar wrists, extensor elbows, axillary areas, central abdomen, genitalia, buttocks, and anterior thighs. The papular lesions affecting the shaft and glans penis as well as the scrotum are almost diagnostic. Facial lesions in adults are absent. Difficult cases include the very young, who may have pustules on the face or scalp. - The rash consists of pruritic papules, but a diagnostic linear burrow consisting of a very fine scale is often seen in the interdigital web area or on the volar wrists (Fig. 34-3A). Nodular lesions commonly occur on male genitalia (Fig. 34-3B).
- The diagnosis is confirmed by scraping a small linear scaly burrow to reveal the female mite, her eggs, or fecal material under the microscope. Recovery of the diagnostic mite on scraping is often difficult in the excessively clean patient or patients that have been partially treated. Less commonly the diagnosis is established by visualizing the mite on a skin biopsy (Fig. 34-4).
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