In which patient demographic is Henoch-Schonlein purpura most commonly found?

Henoch-Schonlein purpura (HSP), also known as IgA vasculitis, is most commonly seen in children, particularly those between the ages of 2 and 6 years. This condition is characterized by a tetrad of symptoms: purpura (typically on the buttocks and legs), abdominal pain, arthralgia or arthritis, and renal involvement, such as hematuria and proteinuria.

The pathophysiology involves deposition of IgA-containing immune complexes in small blood vessels, leading to vasculitis. While HSP can occur in all age groups, its peak incidence is distinctly in the pediatric population.

In infants, the condition is rare, and while adults may experience similar symptoms, adult cases are less common and tend to have a different clinical presentation. Pregnant women do not fall into a demographic particularly affected by HSP either, as the condition predominantly affects younger individuals. Thus, the prominence of HSP in children makes this demographic the correct choice.