Clinical evaluation and pathomechanism of urticaria-like skin eruption in systemic lupus erythematosus.

Clinical observations of 10 SLE patients having urticaria-like skin symptoms showed that the clinical process of urticaria found in patients suffering from SLE differs from the classic one. On the basis of histological and immunohistological studies in 5 cases, a characteristic histological manifestation of leukocytoclastic vasculitis of small veins in the upper third of the cutis was found. The various urticaria-like skin symptoms in SLE are caused by immunocomplexes of various components. The continuous presence of urticaria is caused by C-activating formation of anaphylatoxin. The appearance of urticaria in SLE patients is an unfavourable precursor which has been confirmed by statistical analysis.