IgA vasculitis is caused by an abnormal response of the immune system. The result is inflammation in the microscopic blood vessels in the skin. Blood vessels in the joints, kidneys, or the intestines may also be affected. It is unclear why this occurs.

The syndrome is mostly seen in children between ages 3 and 15 years, but it may be seen in adults. It is more common in boys than in girls. Many people who develop this disease had an upper respiratory infection in the weeks before.

Symptoms and features of IgA vasculitis may include:

• Purple spots on the skin (purpura). This occurs in nearly all children with the condition. This most often occurs over the buttocks, lower legs, and elbows.
• Abdominal pain.
• Joint pain.
• Abnormal urine (may have no symptoms).
• Diarrhea, sometimes bloody.
• Hives or angioedema.
• Nausea and vomiting.
• Swelling and pain in the scrotum of boys.
• Headache.

The health care provider will look at your body and look at your skin. The physical exam will show skin sores (purpura, lesions) and joint tenderness.

Tests may include:

• Urinalysis should be done in all cases.
• Complete blood count. The platelet should be normal.
• Coagulation tests: these should be normal.
• Skin biopsy, especially in adults.
• Blood tests to look for other causes of blood vessel inflammation, such as systemic lupus erythematosus, ANCA-associated vasculitis or hepatitis.
• In adults, a kidney biopsy should be done.
• Imaging tests of the abdomen if pain is present.

There is no specific treatment. Most cases go away on their own. Joint pain may improve with NSAIDs such as naproxen. If symptoms do not go away, you may be prescribed a corticosteroid medicine such as prednisone.

The disease most often gets better on its own. Two thirds of children with IgA vasculitis have only one episode. One third of children have more episodes. People should have close medical follow-up for 6 months after episodes to look for signs of kidney disease. Adults have a greater risk of developing chronic kidney disease.

Complications may include:

• Bleeding inside the body
• Blocking of the intestine (in children)
• Kidney problems (in rare cases)

Contact your provider if:

• You develop symptoms of IgA vasculitis, and they last for more than a few days.
• You have colored urine or low urine output after an episode.

Immunoglobulin A vasculitis; Leukocytoclastic vasculitis; Henoch-Schönlein purpura; HSP; IgA vasculitis - Henoch-Schönlein purpura

Dinulos JGH. Hypersensitivity syndromes and vasculitis. In: Dinulos JGH, ed. Habif's Clinical Dermatology. 7th ed. Philadelphia, PA: Elsevier; 2021:chap 18.

Stone JH. The systemic vasculitides. In: Goldman L, Cooney KA, eds. Goldman-Cecil Medicine. 27th ed. Philadelphia, PA: Elsevier; 2024:chap 249.

Stone JH. Immune complex–mediated small vessel vasculitis. In: Firestein GS, McInnes IB, Koretzky GA, Mikuls TR, Neogi T, O'Dell JR, eds. Firestein & Kelley's Textbook of Rheumatology. 12th ed. Philadelphia, PA: Elsevier; 2025:chap 92.

Sunderkötter CH, Zelger B, Chen KR, et al. Nomenclature of cutaneous vasculitis: Dermatologic addendum to the 2012 revised International Chapel Hill Consensus Conference Nomenclature of Vasculitides. Arthritis Rheumatol. 2018;70(2):171-184. PMID: 29136340 pubmed.ncbi.nlm.nih.gov/29136340/.

Updated by: Diane M. Horowitz, MD, Rheumatology and Internal Medicine, Northwell Health, Great Neck, NY. Review provided by VeriMed Healthcare Network. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.