Cutaneous leukocytoclastic vasculitis: correlation of histopathological changes with clinical severity and course.

We have examined 61 histopathologic specimens from 54 patients with cutaneous leukocytoclastic vasculitis (LV). They were examined without knowledge of clinical disease for the following characteristics: vessel wall inflammation, erythrocyte extravasation, depth of infiltrate, leukocytoclasis, fibrinoid necrosis, epidermal necrosis and fibrin thrombi. Independent of the histopathological study, the following clinical observations were recorded: type of lesion, severity and the presence and type of systemic disease. The severity score was based on the extent of cutaneous disease, the presence of systemic disease and the difficulty of disease control. The clinical and histological features were then compared using an analysis of variance. Statistically significant results included (1) the relation of clinical severity to vessel wall inflammation, leukocytoclasis, overall histologic severity; and (2) the mildness of histological changes in patients with urticarial lesions. Thus, we have demonstrated that the severity of histopathologic changes seen on skin biopsy is (1) predictive of clinical severity, (2) may correlate with the type of skin lesion observed, but (3) does not correlate with the presence or absence of internal vasculitic involvement.