What is IgA Vasculitis?
IgA vasculitis is inflammation of small blood vessels caused by deposits of IgA antibodies. It produces a characteristic purple rash on the legs and buttocks, joint pain, abdominal pain and, in some patients, kidney inflammation. It is the commonest vasculitis in children, usually self-limiting, but tends to be more serious in adults.
Also called: Henoch-Schönlein purpura, HSP
Who gets IgA Vasculitis?
Most commonly children between 3 and 15, often after an upper respiratory infection. In adults it is less common but more likely to involve the kidneys and to persist. It occurs slightly more often in males, and more frequently in the winter months following viral illness.
What are the symptoms of IgA Vasculitis?
Not everyone has every symptom below, and having one does not confirm the diagnosis. These are the features that most often lead to assessment:
- Raised purple spots on the lower legs and buttocks that do not fade under pressure
- Joint pain and swelling, usually knees and ankles
- Crampy abdominal pain, sometimes severe, occasionally with blood in the stool
- Blood or protein in the urine — sometimes visible, more often detected only on testing
- Swelling of the ankles, hands or scrotum
- Nausea and vomiting
- Headache and fever
How is IgA Vasculitis diagnosed?
The combination of the rash distribution with joint, abdominal or kidney features is usually enough to make the diagnosis clinically.
Skin biopsy with immunofluorescence shows IgA deposits and confirms it where the picture is unclear.
Urine testing for blood and protein is done at diagnosis and repeated regularly afterwards — kidney involvement can appear weeks after the rash has settled, which is the main reason follow-up continues after the patient feels well.
Blood pressure, kidney function and, where protein loss is significant, a kidney biopsy complete the assessment.
How is IgA Vasculitis treated?
Most cases need only supportive treatment: rest, adequate fluids and simple analgesia. The rash and joint pain settle over several weeks.
Corticosteroids help severe abdominal pain and joint symptoms, though they do not prevent kidney involvement.
Significant kidney disease is treated with immunosuppression — corticosteroids with mycophenolate, azathioprine or cyclophosphamide depending on biopsy findings — and with ACE inhibitors to reduce protein loss.
Follow-up urine testing continues for six to twelve months after the rash resolves, in both children and adults.
Living with IgA Vasculitis
In children the outlook is excellent and the great majority recover completely. In adults kidney involvement is more common and can lead to chronic kidney disease if missed, which is why urine testing continues well after the visible illness has gone. Recurrence within the first year happens in around a third of cases and is usually milder.
When should you see a rheumatologist?
A purple rash on the legs and buttocks with joint or abdominal pain should be assessed. Severe abdominal pain, visible blood in the urine or stool, or reduced urine output needs urgent review.
Common questions about IgA Vasculitis
How long does IgA vasculitis last?
The rash and joint symptoms usually settle over four to six weeks. Kidney involvement can appear later, which is why urine is tested for six to twelve months afterwards even when everything looks resolved.
Is it more serious in adults?
Yes. Kidney involvement is more frequent and more likely to persist in adults, so monitoring is more intensive and treatment is more often needed.
Will it come back?
Around a third of patients have a recurrence within the first year, usually milder and shorter than the first episode.
This page is general information to support a consultation. It is not a diagnosis, and it does not replace an assessment by a doctor who has examined you.