How common is henoch schonlein purpura?

Henoch Schoenlein: Not very common. In the us about 15 people in 100, 000 develop henoch schoenlein purpura, but it varies in different countries. In england it's 20 people in 100, 000. It primarily affects children between 2 and 13 years of age, but adults can be affected as well.

Commonly uncommon: Quoted figures are between 6 and 22 per 100,000 children. So if you estimate 1 in 10,000, most pediatricians will see a few cases in their careers, and most people (friends, neighbors and family) will never have heard of it. Consider it a common disease that is uncommonly seen.