Bullous lesions in Henoch-Schönlein purpura.

Henoch-Schönlein purpura (HSP) is a small-vessel vasculitis characterized by purpura, arthritis, abdominal pain, and hematuria. It is the most common form of vasculitis affecting children. The skin manifestations typically present as palpable purpura over the buttock and the lower extremities, but bullous lesions are particularly rare in children.