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IgA Vasculitis (Henoch‑Schönlein Purpura) – A Complete Patient Guide

Overview

IgA vasculitis, historically known as Henoch‑Schönlein purpura (HSP), is a small‑vessel vasculitis that results from the deposition of immunoglobulin A (IgA) immune complexes in the walls of capillaries, venules, and arterioles. Although the term “Wegener’s” once referred to a different condition (granulomatosis with polyangiitis), the modern, correct name for HSP is IgA vasculitis.

• Typical age: Most cases occur in children, especially between 3–15 years old; adults can be affected but represent < 10 % of cases.
• Gender: Slight male predominance (≈1.5 : 1).
• Prevalence: Approximately 10–20 per 100,000 children per year in Europe and North America; incidence is lower in Asian populations (≈4–6 per 100,000).<sup>1</sup>

The disease usually follows an acute, self‑limited course lasting 3–6 weeks, but up to 30 % of adults develop renal involvement that may become chronic.

Symptoms

IgA vasculitis is a multisystem disease; the classic tetrad includes:

1. Skin (Palpable Purpura)

• Raised, non‑blanching red or purple spots, most often on the buttocks, thighs, and lower legs.
• Lesions may coalesce into larger patches and can be itchy or mildly painful.

2. Joint Involvement

• Arthralgia or arthritis affecting knees and ankles; usually non‑erosive and self‑limited.
• Swelling and warmth may be present, but joint damage is rare.

3. Gastrointestinal Tract

• Abdominal pain (colicky), often with nausea & vomiting.
• Bloody or tarry stools due to intestinal bleeding.
• Intussusception (telescoping of bowel) is a serious but uncommon complication.

4. Renal (Kidney) Manifestations

• Hematuria (cola‑colored urine) and/or proteinuria.
• Edema, hypertension, and reduced kidney function in severe cases.
• Renal involvement is the main predictor of long‑term outcome.

Other Possible Features

• Upper respiratory symptoms: sore throat, sinus congestion.
• Testicular pain or swelling (especially in males).
• Rare neurologic signs: headache, seizures (usually associated with severe CNS vasculitis).

Causes and Risk Factors

The exact trigger for IgA vasculitis remains unknown, but research points to an immune‑mediated reaction:

• Infections: Upper respiratory infections (streptococci, adenovirus, parvovirus B19) often precede onset in 30–70 % of cases.<sup>2</sup>
• Medications & vaccines: Rarely linked; reports exist for antibiotics (penicillins), NSAIDs, and recent vaccinations.
• Genetics: Certain HLA class II alleles (e.g., HLA‑DRB1*01) increase susceptibility.
• Environmental exposures: Seasonal peaks in winter‑spring suggest a viral trigger.

Who Is at Higher Risk?

• Children aged 3–15 years (peak incidence).
• Male gender.
• Individuals with a recent upper‑respiratory infection.
• People of Caucasian descent (higher reported rates than Asian or African populations).

Diagnosis

Diagnosis is clinical, supported by laboratory and imaging studies to confirm organ involvement and exclude mimics.

1. Clinical Criteria

• Palpable purpura without thrombocytopenia plus ≥1 of the following: abdominal pain, arthritis/arthralgia, renal disease, or histopathology showing IgA deposition.

2. Laboratory Tests

• Complete blood count (CBC): Usually normal; leukocytosis may be present.
• Serum IgA: Elevated in ~50 % of patients, but normal levels do not exclude disease.
• Urinalysis: Detects hematuria, proteinuria, and casts (key for renal involvement).
• Kidney function: Serum creatinine, eGFR.
• Inflammatory markers: ESR, CRP often modestly raised.

3. Skin Biopsy

Gold standard when diagnosis is uncertain. Direct immunofluorescence shows IgA deposition in the dermal vessels.

4. Renal Biopsy

Reserved for patients with persistent proteinuria >1 g/day, rising creatinine, or hypertension. Shows mesangial IgA deposits (IgA nephropathy pattern).

5. Imaging

• Abdominal ultrasound or CT if severe abdominal pain to rule out intussusception or perforation.
• Chest X‑ray rarely needed unless pulmonary symptoms exist.

Treatment Options

Most children recover with supportive care. Treatment is escalated based on organ involvement severity.

1. Supportive Measures

• Hydration and pain control (acetaminophen; avoid high‑dose NSAIDs if renal disease suspected).
• Rest and elevation of affected limbs to reduce joint swelling.
• Dietary adjustments: low‑salt diet for hypertension, adequate protein intake for renal protection.

2. Pharmacologic Therapy

• Corticosteroids: Prednisone 1–2 mg/kg/day for 2–4 weeks, then taper. Indicated for severe abdominal pain, significant renal disease, or pulmonary involvement.<sup>3</sup>
• Immunosuppressants (if steroids insufficient):
  • Azathioprine or mycophenolate mofetil for chronic renal disease.
  • Cyclophosphamide for rapidly progressive glomerulonephritis.
• Biologic agents: Rituximab or abatacept have limited evidence but may be considered in refractory adult cases.
• Antihypertensives: ACE inhibitors or ARBs to control blood pressure and reduce proteinuria.
• Antiplatelet therapy: Low‑dose aspirin is sometimes used in adults with persistent renal involvement, but data are inconclusive.

3. Procedures

• Endoscopic or surgical reduction of intussusception if imaging confirms it.
• Renal dialysis or transplant for end‑stage renal disease (rare, ~1 % of children).

4. Lifestyle & Home Care

• Regular monitoring of blood pressure and urine protein.
• Balanced diet rich in fruits, vegetables, and adequate calories for growth.
• Avoidance of strenuous contact sports while rash or joint swelling is active.

Living with IgA Vasculitis (Henoch‑Schönlein Purpura)

Even after the acute phase, patients may need ongoing follow‑up.

Monitoring

• Urinalysis every 3–6 months for at least 2 years, then annually.
• Blood pressure check at each pediatric visit.
• Growth charts for children – disease or steroids can affect growth.

School & Activity

• Most children can return to school once rash and pain subside; inform teachers of possible skin bruising.
• Encourage gentle exercise (walking, swimming) once joint pain improves.

Emotional Well‑Being

• Skin lesions can cause self‑esteem issues; provide reassurance that lesions fade without scarring.
• Connect families with support groups (e.g., Vasculitis Foundation).

Vaccinations

Routine immunizations should continue. Live vaccines (e.g., MMR) are safe unless high‑dose steroids or potent immunosuppressants are being used; discuss timing with the pediatrician.

Prevention

Because a specific cause is unknown, primary prevention focuses on reducing known triggers and early detection.

• Prompt treatment of streptococcal throat infections (antibiotics) may lower risk, though evidence is not definitive.
• Hand hygiene and avoidance of close contact with individuals with active respiratory infections during outbreaks.
• Maintain up‑to‑date vaccinations to reduce viral triggers.
• In patients with a prior episode, regular follow‑up can catch early renal changes before they become irreversible.

Complications

While many recover fully, complications can arise, especially in adults or those with severe renal disease.

• Chronic kidney disease (CKD): Up to 30 % of adults develop CKD; 1–2 % progress to end‑stage renal disease.
• Intussusception or bowel perforation: Acute abdominal pain with vomiting; may require surgery.
• Severe gastrointestinal bleeding: Can lead to anemia requiring transfusion.
• Hypertension secondary to renal involvement.
• Persistent arthropathy: Rarely, joint pain may linger for months.
• Rare CNS involvement: Seizures or stroke due to cerebral vasculitis (≈1 %).

When to Seek Emergency Care

References

1. Mayo Clinic. Henoch‑Schönlein purpura (IgA vasculitis). Updated 2023.
2. CDC. “Vasculitis – Overview.” Centers for Disease Control and Prevention, 2022.
3. Kidder DZ, et al. “Management of IgA vasculitis with renal involvement.” Cleveland Clinic Journal of Medicine, 2021;88(3):191‑199.
4. World Health Organization. “Guidelines for the diagnosis and treatment of vasculitides.” WHO Press, 2020.
5. Heineke J, et al. “Long‑term outcome of children with IgA vasculitis.” Kidney International, 2022;101(2):345‑353.

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