Pyoderma gangrenosum.

A 3.5-year-old girl presented with skin lesions beginning as a small pustule that progressed to very painful large ulcer with rolled up edges and irregular borders. At presentation, active ulcers were present over the left elbow. There were healed ulcers with scarring present on the chest, back, both thighs and abdominal wall. This child had negative antinuclear antibody, cytoplasmic antinuclear cytoplasmic antibody, antiphospholipid antibodies and tests for hepatitis B and C. She did not have any symptoms to suggest ulcerative colitis. Her colonoscopy was absolutely normal. Histopathology from her skin lesion was consistent with pyoderma gangrenosum.