A 33-year-old man with lupus sought care after a week of itchy, burning plaques on his hands, elbows, knees, and feet. A week later, the rash had spread to his thighs, chest, abdomen, and back, forming fixed, ring-shaped and target-like welts with purplish rims. They looked like hives. They were not.
A skin biopsy showed leukocytoclastic vasculitis, a form of small blood vessel inflammation in which white blood cells invade the vessel walls. The diagnosis was urticarial vasculitis, a rare condition in which inflamed blood vessels in the skin produce hive-like welts.
