Henoch-Schonlein purpura (HSP) is defi ned as a primary systemic vasculitis of small vessels characterized by predominantly IgA immune deposits on the walls of the capillaries, venules, and arteriales. It typically involves skin, intestines, and glomeruli and is associated with arthritis and arthralgia. Robert Willan (1757-1812), the founder of modern dermatology, was the fi rst to clearly describe vasculitis and its signifi cance. This article analyzes the fundamental history of HPS. (Acta Med Colomb 2007; 32: 97-100)
