Scleredema is characterized by hard, thick skin, typically on the upper back, neck, and shoulders. It may have a waxy appearance. It is an uncommon skin manifestation of diabetes mellitus, and patients may have myeloma. Scleredema should not be confused with morphea or progressive systemic sclerosis. Cause is unknown, but biopsy shows deposition of collagen bundles and mucin in the dermis.
Image courtesy of Chrysalyne A. Schmults, MD, and the Dermatology Journal Online.