Histopathology of the decubitus ulcer.

The histologic studies of the decubitus ulcer spectrum, which include blanchable erythema, nonblanchable erythema, decubitus dermatitis, decubitus ulcer, and the black eschar/gangrene reveal a dynamic process. The initial change occurs in the vessels of the papillary dermis. This is followed by necrosis of skin structures. The eschar/gangrene represents a full-thickness defect due either to prolonged ischemia and anoxemia or a sudden large vessel occlusion caused by shearing injury.