Synopsis
Recognise IgA vasculitis from palpable purpura with joint, gastrointestinal and renal involvement, exclude sepsis and other small-vessel disease, detect adult nephritis and bowel emergencies, and organise supportive, organ-specific and long-term renal care.
- IgA vasculitis classically combines non-thrombocytopenic palpable purpura, usually on dependent legs or buttocks, with arthralgia or arthritis, abdominal pain and renal abnormality.
- Check observations, full blood count and platelets, coagulation, creatinine, electrolytes, albumin, CRP, urinalysis, microscopy, ACR or PCR and blood pressure at presentation.
- A normal platelet count helps distinguish vasculitic purpura from thrombocytopenic bleeding but does not exclude meningococcal sepsis or DIC early.
- Skin biopsy of a fresh lesion shows leukocytoclastic vasculitis; direct immunofluorescence for IgA supports diagnosis when the phenotype is atypical.
- Severe abdominal pain requires ultrasound or CT and surgical review for intussusception, ischaemia, bleeding and perforation before symptoms are attributed to uncomplicated bowel oedema.
- Kidney biopsy is indicated for rapidly declining function, substantial persistent proteinuria, nephrotic or nephritic syndrome and other high-risk adult disease because histology changes treatment and prognosis.
- Mild skin and joint disease is managed with hydration, activity adjustment and cautious analgesia; avoid NSAIDs when renal disease, GI bleeding or dehydration is present.
- Glucocorticoid can shorten severe joint or abdominal symptoms after surgical and infectious causes are excluded but should not be given solely to prevent future nephritis.
- Manage established IgA-vasculitis nephritis with pressure and proteinuria reduction, usually ACE inhibitor or ARB when appropriate, and nephrology-directed immunosuppression only for selected active severe disease.
- Continue urine, protein, blood pressure and eGFR monitoring for at least six months and longer in adults or after any nephritis because renal disease can appear after the rash fades.
Key red flags
Non-blanching rash with hypotension, fever, neck stiffness or rapid progression requires immediate meningococcal and sepsis treatment before vasculitis classification.
Severe colicky abdominal pain, guarding, bilious vomiting, GI bleeding or a palpable mass suggests intussusception, ischaemia or perforation.
Rising creatinine, oliguria, hypertension, nephrotic proteinuria or red-cell casts requires urgent nephrology and possible kidney biopsy.
Scrotal pain requires torsion assessment; oedema and haematuria do not make an acute scrotum automatically vasculitic.
Adult-onset disease has greater CKD risk and needs longer urine, protein, pressure and eGFR follow-up than a transient rash suggests.
Colicky pain, vomiting, occult or overt bleeding and bowel-wall oedema can precede purpura and may progress to intussusception.
Microscopic blood, protein, hypertension, oedema or creatinine change may emerge days to weeks after other symptoms.
Toxic physiology, fever and rapidly spreading petechiae or ecchymoses require immediate sepsis treatment regardless of a possible vasculitis history.
Investigation priorities
Distinguish non-thrombocytopenic vasculitis from platelet, DIC and microangiopathic bleeding disorders.
Management branches
Palpable non-blanching rash occurs with joint, abdominal or urinary symptoms.
- Assess sepsis physiology first, then map rash, joints, abdomen, oedema, scrotum, pressure and urine and review infection and medicines.
- Obtain blood count, platelets, coagulation, renal, albumin, inflammatory markers, microscopy and quantitative protein.
- Use fresh skin biopsy when atypical and establish a written renal-monitoring schedule even if initial urine is normal.