Henoch-Schönlein purpura (IgA vasculitis)

For a lay person:

Henoch-Schönlein purpura is an inflammation of small blood vessels that causes a raised, purplish rash, usually on the legs and buttocks. It is most common in children after a throat or chest infection, but adults can get it too. It can also cause joint pain, tummy pain and, in some people, kidney problems.

For a trained medical person:

An IgA-mediated small-vessel vasculitis (IgA vasculitis), often following upper respiratory infection, presenting with palpable purpura with normal platelet count, arthralgia, abdominal pain and nephritis. Diagnosis is clinical, supported by urinalysis, blood pressure, renal function and, when atypical or in adults, skin or renal biopsy showing IgA deposition. Management is mostly supportive with analgesia and hydration; corticosteroids are used for severe abdominal or renal involvement, and urine and blood pressure are monitored for months to detect nephritis.

In Chinese medicine:

Liu and Tseng's textbook differentiates this condition into these patterns: Stagnant Heat Obstructing Collaterals; Yin Deficiency and Blood Heat; Spleen Not Controlling Blood. Treatment follows the pattern a patient presents with, not the Western diagnosis alone.

When to get help: Get urgent care for severe tummy pain, blood in vomit or stool, a swollen scrotum, reduced urine, or very dark or bloody urine. Keep follow-up urine tests even after the rash settles, and check with a doctor before using herbs if kidney function is affected.