HenochSchönlein

Henoch-Schönlein purpura, also known as IgA vasculitis, is a small-vessel vasculitis characterized by deposition of IgA-containing immune complexes in the walls of small vessels. It most often affects children, though adults can be affected, and symptoms commonly follow an upper respiratory infection or other immune stimulus by days to a couple of weeks.

The classic clinical features include palpable purpura, typically on the buttocks and legs, often accompanied by arthralgia or arthritis of the knees and ankles. Abdominal involvement is common and can present as colicky pain, nausea, vomiting, or, less frequently, gastrointestinal bleeding. Kidney involvement ranges from microscopic hematuria and mild proteinuria to nephritic syndrome; in some cases it can progress to more significant renal disease.

Pathophysiology involves IgA-dominant immune complex deposition in small vessels, leading to inflammation. Triggers may include infections, vaccines, or other immune perturbations, but in many cases the exact cause is not identified. Diagnosis is primarily clinical, supported by laboratory tests and, when needed, tissue biopsy showing IgA deposition in affected vessels. Complement levels are typically normal, and the diagnosis may be confirmed with a skin or renal biopsy if the presentation is atypical.

Management is mainly supportive. Adequate hydration and analgesia are standard; corticosteroids may be used for severe abdominal pain or significant renal involvement, though they do not consistently modify long-term outcomes. Severe renal disease may require nephrology input and, in rare cases, immunosuppressive therapy.

Prognosis is generally favorable in children, with most cases resolving within weeks to months. However, renal involvement can persist or progress in some patients, and adults have a higher risk of renal complications. The condition is named for Johann Luke Schönlein and Isidor Henoch, who described the disease in the 19th century.