Painful urticarial lesions that persist for >24 hours should raise suspicion for urticarial vasculitis (UV). UV is a rare, immune complex–mediated, small-vessel leukocytoclastic vasculitis involving complement activation. Although often idiopathic, UV can be associated with infection, medications, malignancies, and autoimmune conditions such as systemic lupus erythematosus (SLE). Skin biopsy demonstrating leukocytoclastic vasculitis establishes the diagnosis, while complement levels help classify UV and inform prognosis: Hypocomplementemia is associated with a greater risk of systemic involvement and a more severe disease course, requiring different treatment. In this case, hypocomplementemic UV occurred in the setting of the patient…
Comment
Painful urticarial lesions that persist for >24 hours should raise suspicion for urticarial vasculitis (UV). UV is a rare, immune complex–mediated, small-vessel leukocytoclastic vasculitis involving complement activation. Although often idiopathic, UV can be associated with infection, medications, malignancies, and autoimmune conditions such as systemic lupus erythematosus (SLE). Skin biopsy demonstrating leukocytoclastic vasculitis establishes the diagnosis, while complement levels help classify UV and inform prognosis: Hypocomplementemia is associated with a greater risk of systemic involvement and a more severe disease course, requiring different treatment. In this case, hypocomplementemic UV occurred in the setting of the patient…