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Fig. 16.2 Primary systemic amyloidosis. Characteristic periorbital purpuric plaques. |
Cutaneous lesions are seen in about 30% of cases of primary or myeloma-related systemic amyloidosis. The most common skin lesions are petechiae or ecchymoses due to amyloid deposition within blood vessel walls with subsequent fragility and dermal hemorrhage. These are often seen at sites predisposed to trauma, such as the hands or intertriginous areas. Pinching the skin gives characteristic purpuric lesions known as “pinch purpura.” Purpura around the eyes may occur spontaneously but is also seen following proctoscopy or vomiting (“postproctoscopic purpura”) (Fig. 16-2). Waxy papules, nodules, or plaques may be present. Less common manifestations include sclerodermoid plaques, bullae, alopecia, and nail dystrophy.