Urticarial vasculitis.

Urticarial vasculitis is a clinico-pathologic entity typified by recurrent episodes of urticaria that have the histopathologic features of leukocytoclastic vasculitis. The cutaneous features may include painful, burning or pruritic skin lesions, the persistence of individual lesions greater than 24 hours, palpable purpura, pronounced central clearing of lesions, and residual hyperpigmentation following resolution. However, because clinical characteristics of urticarial vasculitis may overlap with those of allergic urticaria, confirmation of the diagnosis requires a lesional skin biopsy. This condition is idiopathic in many patients but can also occur in the context of autoimmune disorders, infections, drug reactions, or as a paraneoplastic syndrome. In idiopathic urticarial vasculitis common laboratory findings are an elevation of erythrocyte sedimentation rate and reduction of serum complement. An association between urticarial vasculitis and systemic lupus erythematosus has been hypothesized as some clinical manifestations of disease overlap and C1q autoantibodies may be present in both diseases. Normo-complementemic patients usually have minimal or no systemic involvement and often have a better prognosis. On-the-other-hand, hypocomplementemic patients have the propensity to have more severe multi-organ involvement. Response to treatment is variable and a wide variety of therapeutic agents may be efficacious. Initial recommendations for treatment of urticarial vasculitis manifest only as non-necrotizing skin lesions include antihistamines, dapsone, colchicine, hydroxychloroquine or indomethacin, but corticosteroids are often required. With necrotizing skin lesions or visceral involvement, corticosteroids are regularly indicated. Cases of severe corticosteroid resistant urticarial vasculitis or where corticosteroid morbidity is evident [table: see text] may require treatment with other immunosuppressive agents such as azathioprine, cyclophosphamide, or cyclosporine.