A positive reaction to skin testing with streptokinase and streptodornase at 4 and 24 hours has been reported to help determine a causative association with bacterial infection. The erythrocyte sedimentation rate in patients with EED is often elevated. EED is a type of necrotizing vasculitis. There is not a specific histological finding that can single out the diagnosis of EED from other leukocytoclastic diseases. However, the simultaneous presence of several histologic findings can help distinguish the disease from others.
Early lesions show vasculitis in the small vessels of the upper and mid-dermis.
Furthermore, a perivascular infiltrate consisting mainly of PMNs, nuclear dust and to a lesser extent, macrophages, lymphocytes and eosinophils is present throughout the dermis. The infiltrate may accumulate between collagen bundles. Granulation tissue and fibrosis in the dermis characterize older lesions. Several studies and clinical experience have shown good response of the disease to dapsone, therefore making it the treatment of choice. Dosage depends on each patient.