Urticarial vasculitis appearing in the progression of systemic sclerosis

We report a case of urticarial vasculitis that appeared during the course of limited cutaneous systemic sclerosis. The urticarial lesions responded to systemic administration of prednisolone. After the appearance of urticarial vasculitis, the progression of scleroderma in distal sites of her elbow and knee joint became apparent. We consider this case to be consistent with limited cutaneous systemic sclerosis. The patient started treatment with prednisolone and her edema as well as scleroderma softened gradually. We analyzed, by immunohistochemistry, the number of tryptase-positive mast cells of this case in the lesions of urticarial vasculitis as well as systemic sclerosis. The number of tryptase-positive mast cells in the lesions of urticarial vasculitis as well as systemic sclerosis was significantly increased compared to normal skin (P < 0.05 and P < 0.005, respectively). We demonstrate that, in the present case, mast cells might be involved in both courses of urticarial vasculitis and systemic sclerosis as a common factor.