The syndrome is usually seen in children, but people of any age may be affected. It is more common in boys than in girls. Many people with Henoch-Schonlein purpura had an upper respiratory illness in the previous weeks.
Update Date 4/28/2015
Updated by: Gordon A. Starkebaum, MD, Professor of Medicine, Division of Rheumatology, University of Washington School of Medicine, Seattle, WA. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.