Iga Vasculitis

Disclaimer: This information is intended for educational purposes and as a clinical reference for healthcare professionals. It should not be used as a substitute for professional medical advice, diagnosis, or treatment. Clinical decisions must always be made by a qualified healthcare provider, taking into account the individual patient's circumstances and current clinical guidelines. Dosage information, while provided, should always be verified against official drug labeling and current prescribing guidelines.

Overview

• Definition: IgA Vasculitis (IgAV), formerly known as Henoch-Schönlein Purpura (HSP), is the most common form of systemic small vessel vasculitis in children, characterized by the deposition of IgA1-containing immune complexes in small blood vessels. It typically affects the skin, joints, gastrointestinal tract, and kidneys.
• Epidemiology:
  • Incidence: Approximately 10-20 cases per 100,000 children annually. Less common in adults, with an incidence of about 0.8-1.8 cases per 100,000 adults annually.
  • Age: Predominantly affects children aged 3-15 years, with a peak incidence between 4 and 7 years.
  • Sex: Slightly more common in males (male-to-female ratio of 1.5:1).
  • Seasonality: Often occurs in the fall and winter months, frequently preceded by an upper respiratory tract infection.
• Classification: IgAV is generally classified based on age of presentation (pediatric vs. adult) due to differences in severity and prognosis. There are no specific subtypes beyond this distinction, although the presence and severity of organ involvement (e.g., IgAV with nephritis) are crucial for management.

Pathophysiology

• Mechanism: The underlying mechanism involves the deposition of circulating immune complexes containing aberrantly glycosylated IgA1 in the walls of small vessels (post-capillary venules). This IgA1 has a deficiency in galactose in its O-linked glycans in the hinge region. These abnormal IgA1 molecules are recognized by IgG or IgA autoantibodies, forming immune complexes that deposit in various tissues. This deposition triggers complement activation (primarily alternative pathway, leading to C3 activation) and inflammatory responses, resulting in leukocytoclastic vasculitis and tissue damage.
• Risk Factors:
  • Infections: Most commonly, upper respiratory tract infections (especially Group A Streptococcus, but also viral infections like parvovirus B19, adenovirus, influenza, Epstein-Barr virus).
  • Medications: Certain drugs (e.g., NSAIDs, antibiotics like ampicillin/penicillin, captopril, enalapril) have been implicated, though causality is often difficult to establish.
  • Vaccinations: Rarely, certain vaccines (e.g., MMR, yellow fever) have been reported as triggers.
  • Environmental: Insect bites, cold exposure.
  • Genetics: Genetic predispositions, including HLA-B35, HLA-DRB1*04, and polymorphisms in TNF-α, are associated with increased risk.
• Protective Factors: No specific protective factors have been definitively identified.

Clinical Presentation

Signs and Symptoms

• Cardinal Features: The classic tetrad of IgAV includes:
  1. Palpable Purpura: The hallmark skin lesion, non-thrombocytopenic (platelet count normal), typically symmetrically distributed on the lower extremities and buttocks. Lesions can evolve from macules/papules to petechiae, ecchymoses, bullae, or necrotic ulcers. Purpura does not blanch with pressure. It usually appears in crops over days to weeks.
  2. Arthralgia/Arthritis: Affects approximately 75% of patients. It is typically migratory, non-deforming, and affects large joints (knees, ankles, less commonly hips, elbows, wrists). Joint pain often accompanied by periarticular swelling and tenderness.
  3. Abdominal Pain: Occurs in 50-75% of patients. It is typically colicky, diffuse, and can be severe. May be accompanied by nausea, vomiting, diarrhea, and gastrointestinal bleeding (hematochezia, melena, or occult blood). Abdominal symptoms can sometimes precede the rash.
  4. Renal Involvement (IgAV Nephritis): Occurs in 20-50% of patients. Manifests as microscopic or macroscopic hematuria, proteinuria (ranging from trace to nephrotic range, i.e., >3.5 g/day in adults or >40 mg/m²/hr in children), hypertension, and rarely, acute kidney injury. Renal involvement is more common and often more severe in adults.
• Early Signs: Palpable purpura is often the initial manifestation, followed shortly by arthralgia and/or abdominal pain. Edema of the hands, feet, face, or scrotum can also be an early sign, particularly in young children.
• Advanced Signs: Severe gastrointestinal bleeding, intussusception, bowel perforation, severe renal failure requiring dialysis, or central nervous system (CNS) complications (rare).
• Atypical Presentations:
  • Skin: Hemorrhagic bullae, ulcers, urticarial lesions.
  • Gastrointestinal: Protein-losing enteropathy.
  • Scrotal edema/Orchitis: Swelling and pain in the testicles due to vasculitis, which can mimic testicular torsion.
  • Pulmonary: Rarely, pulmonary hemorrhage.
  • Neurological: Headache, seizures, altered mental status, mononeuropathy, polyneuropathy, intracranial hemorrhage (very rare).

Physical Examination

• Inspection:
  • Skin: Palpable purpuric lesions, often coalescing, primarily on dependent areas (lower extremities, buttocks), but can extend to trunk and upper extremities. Look for edema (hands, feet, periocular, scrotal).
  • Joints: Swelling, erythema, and tenderness of large joints.
  • General: Assess for pallor (suggestive of anemia from GI bleeding) and signs of dehydration.
• Palpation: Confirm palpability of skin lesions. Assess for joint tenderness, warmth, and effusions. Abdominal tenderness, distension, or guarding. Scrotal tenderness.
• Special Tests: No specific maneuvers beyond careful examination of affected systems. Assess peripheral pulses, neurological status, and blood pressure.

Diagnostic Approach

The diagnosis of IgAV is primarily clinical, based on the presence of palpable purpura (not due to thrombocytopenia) and at least one of the following criteria: acute onset of abdominal pain, arthritis/arthralgia, or renal involvement (hematuria/proteinuria) according to the EULAR/PRINTO/PRES classification criteria. A skin biopsy provides definitive confirmation.

History Taking

• Key Questions:
  • Rash: Onset, location, progression, character (flat vs. raised).
  • Joints: Location, migratory nature, swelling, pain, limitation of movement.
  • Abdomen: Character of pain (colicky, diffuse), associated nausea, vomiting, diarrhea, blood in stool (color, consistency).
  • Renal: Changes in urine color (dark, bloody), frequency, reduced output, swelling (face, ankles).
  • Preceding Illnesses: Recent upper respiratory infection, sore throat, fever.
  • Medication/Vaccination History: Any new drugs or recent immunizations.
  • Past Medical History: Previous episodes of IgAV, known allergies, chronic illnesses.
• Red Flags:
  • Severe, persistent abdominal pain with distension, guarding, or rigid abdomen: Suggests intussusception, perforation, or acute abdomen.
  • Gross gastrointestinal bleeding (melena, profuse hematochezia): Risk of significant blood loss and shock.
  • Oliguria, anuria, rapidly rising creatinine, or severe hypertension: Indicates severe or rapidly progressive renal involvement.
  • Altered mental status, seizures, focal neurological deficits: Suggests CNS involvement.
  • Sudden onset of scrotal pain/swelling: May mimic testicular torsion (though usually vasculitic).

Laboratory Tests

• First-Line:
  • Complete Blood Count (CBC) with differential: Platelet count is typically normal or elevated (distinguishes from thrombocytopenic purpura). Leukocytosis is common. Anemia may be present with significant GI bleeding.
  • Erythrocyte Sedimentation Rate (ESR) and C-Reactive Protein (CRP): Often elevated, non-specific markers of inflammation.
  • Urinalysis with microscopy: Essential. Look for hematuria (microscopic or macroscopic, presence of red blood cell casts indicates glomerulonephritis) and proteinuria.
  • Serum Creatinine and Blood Urea Nitrogen (BUN): To assess baseline renal function.
  • Serum Albumin: May be decreased if significant proteinuria (nephrotic range) or protein-losing enteropathy is present.
  • Stool guaiac or Fecal Occult Blood Test: To detect occult GI bleeding.
  • ASO titer/Throat culture: If preceding streptococcal infection is suspected, though not diagnostic of IgAV.
• Confirmatory:
  • Skin Biopsy: Gold standard for confirmation, especially in atypical presentations or adults. Biopsy of a fresh purpuric lesion (within 24-48 hours) for light microscopy and direct immunofluorescence (DIF).
    • Light Microscopy: Shows leukocytoclastic vasculitis (perivascular neutrophil infiltration, nuclear dust, fibrinoid necrosis of vessel walls, extravasated red blood cells) in small dermal vessels.
    • Direct Immunofluorescence: Demonstrates IgA1 deposition (often co-deposited with C3) in the walls of dermal post-capillary venules.
  • Renal Biopsy: Indicated if there is severe or progressive renal disease (e.g., persistent nephrotic-range proteinuria >1 g/day, rapidly rising serum creatinine, severe hypertension, or if differentiation from other glomerulonephritides is needed).
    • Light Microscopy: Varies from focal mesangial proliferation to diffuse proliferative glomerulonephritis with crescents.
    • Immunofluorescence: Diffuse mesangial deposition of IgA (primarily IgA1 subclass) and C3 is characteristic, similar to IgA nephropathy.
• Monitoring:
  • Urinalysis, Blood Pressure, and Serum Creatinine: For all patients with renal involvement, and routinely for all patients to detect new renal involvement. Frequency: Weekly for 1 month, then monthly for 6 months, then quarterly for 1 year, and then annually for several years (especially if initial renal involvement).
  • CBC: Periodically if GI bleeding is present or persistent.

Imaging

• Recommended:
  • Abdominal Ultrasound: Indicated for severe or persistent abdominal pain, to evaluate for bowel wall edema, hematoma, or intussusception (especially in children, where ileo-ileal intussusception is a known complication).
• Advanced:
  • Upper and/or Lower Endoscopy/Colonoscopy: In cases of severe or persistent GI bleeding, or if other GI pathologies are suspected.
  • CT Angiography/MRI: Rarely, for suspected CNS vasculitis or pulmonary hemorrhage.

Management

Management of IgAV is primarily supportive. Systemic corticosteroids are used for severe symptoms or significant organ involvement. Immunosuppressants are reserved for severe renal disease or refractory cases.

Acute Management

• Immediate: Address life-threatening complications.
  • Airway: Rarely compromised, but consider if severe angioedema.
  • Circulation: Fluid resuscitation for significant GI bleeding or dehydration. Blood transfusion if severe anemia.
• Stabilization:
  • Pain Management: Acetaminophen is preferred. NSAIDs should be used with extreme caution, if at all, due to potential for GI irritation and renal compromise, especially in patients with abdominal or renal involvement. Opioids may be required for severe abdominal or joint pain.
  • Hydration: Oral or IV fluids as needed.
  • Blood Pressure Control: If hypertension is present, particularly with renal involvement, manage with antihypertensives (e.g., ACE inhibitors/ARBs for proteinuria, calcium channel blockers).
  • Intussusception: Urgent pediatric surgery consultation for reduction (pneumatic or surgical).
• Emergency:
  • Bowel Infarction/Perforation: Surgical emergency.
  • Acute Kidney Injury (AKI): Nephrology consultation; may require dialysis.
  • Severe GI Hemorrhage: Gastroenterology consultation, possibly endoscopy or surgery.

Chronic Management

• Pharmacological:
  • Corticosteroids:
    • Indications: Severe abdominal pain, significant GI bleeding (without perforation/intussusception), severe arthritis limiting mobility, severe edema (e.g., scrotal, facial), and renal involvement with significant proteinuria or declining function.
    • Dosage (Oral): Prednisone 0.5-1 mg/kg/day (maximum 60 mg/day) for 1-2 weeks, followed by a gradual taper over 2-4 weeks. Early initiation (within 72 hours of symptom onset) may reduce the duration and severity of abdominal pain, but does not reliably prevent renal involvement or recurrence.
    • Dosage (IV Pulse): Methylprednisolone 10-30 mg/kg/day (maximum 1 g/day) for 3 consecutive days for severe, rapidly progressive glomerulonephritis or other life-threatening manifestations (e.g., pulmonary hemorrhage, CNS vasculitis).
  • Immunosuppressants (for severe renal disease or refractory cases): Often used in combination with corticosteroids.
    • Cyclophosphamide: Used in severe, rapidly progressive IgAV nephritis (e.g., with extensive crescent formation on biopsy). Dosage varies: typically oral 1.5-2 mg/kg/day or IV pulses (e.g., 500-750 mg/m² every 3-4 weeks).
    • Mycophenolate Mofetil (MMF): May be used as an alternative to cyclophosphamide or for maintenance therapy in IgAV nephritis, or in cases refractory to steroids. Dosage: 10-15 mg/kg twice daily in children (max 1g twice daily); 1-2 g/day in adults.
    • Azathioprine: Used as a steroid-sparing agent for maintenance in some cases of chronic renal involvement. Dosage: 1-3 mg/kg/day.
    • Rituximab: Emerging evidence for refractory severe IgAV, particularly with renal involvement. Typical dosage is 375 mg/m² IV weekly for 4 doses or 1000 mg IV on days 1 and 15.
    • Dapsone: May be considered for chronic or recurrent skin disease in adults.
  • Angiotensin-Converting Enzyme (ACE) Inhibitors/Angiotensin Receptor Blockers (ARBs): Indicated for significant proteinuria (even in the absence of hypertension) to reduce protein excretion and potentially slow progression of renal disease.
• Non-pharmacological:
  • Rest: During the acute symptomatic phase.
  • Diet: Soft, easily digestible diet if significant gastrointestinal symptoms. Avoidance of NSAIDs.
  • Monitoring: Close monitoring of blood pressure.
• Monitoring:
  • Clinical Assessment: Regular follow-up for disease activity, recurrence, or new complications.
  • Renal: All patients, especially those with initial renal involvement, require long-term monitoring.
    • Urinalysis, Blood Pressure, and Serum Creatinine: At least weekly for the first month, then monthly for 6 months, then quarterly for the first year, and annually for several years (up to 5 years or longer if renal involvement was significant).

Treatment Algorithms

• First-Line:
  • Mild Disease (Skin and mild joint involvement only, no severe abdominal pain or renal involvement): Supportive care (hydration, rest, acetaminophen for pain). Most resolve spontaneously within 4 weeks.
  • Moderate Disease (Severe arthralgia limiting mobility, significant abdominal pain, or mild GI bleeding without intussusception/perforation): Oral corticosteroids (e.g., prednisone 0.5-1 mg/kg/day for 1-2 weeks, tapered).
• Second-Line:
  • Severe Renal Involvement (Persistent nephrotic-range proteinuria, rapidly progressive glomerulonephritis, AKI, significant hypertension): High-dose IV methylprednisolone pulse therapy followed by oral prednisone, typically in combination with an immunosuppressant like cyclophosphamide or mycophenolate mofetil. Nephrology consultation is mandatory.
  • Severe Gastrointestinal Involvement (Intussusception, perforation, severe hemorrhage unresponsive to steroids): Surgical intervention; IV corticosteroids.
• Refractory Cases:
  • For severe or persistent disease unresponsive to standard corticosteroids and first-line immunosuppressants (especially severe renal or GI involvement), consider alternative immunosuppressants (e.g., rituximab, tacrolimus) or intravenous immunoglobulin (IVIG).

Complications

• Common:
  • Recurrence: Occurs in 30-40% of patients, usually within 6 months, and often milder than the initial episode.
  • Gastrointestinal: Persistent abdominal pain, recurrent GI bleeding, intussusception (2-3% of children, predominantly ileo-ileal), protein-losing enteropathy.
  • Renal: Chronic kidney disease (CKD), persistent hematuria/proteinuria.
• Serious:
  • Renal Failure: Progression to end-stage renal disease (ESRD) occurs in 1-5% of patients with significant IgAV nephritis, more common in adults and those with nephrotic-range proteinuria or extensive crescents on biopsy.
  • Bowel Infarction/Perforation: A rare but life-threatening emergency of the GI tract.
  • Intracranial Hemorrhage/CNS Vasculitis: Very rare, but can lead to severe neurological deficits or death.
  • Pulmonary Hemorrhage: Extremely rare, but life-threatening.
  • Testicular Torsion/Ischemia: Due to scrotal vasculitis, requiring urgent differentiation from true torsion.
• Long-term: Chronic kidney disease, hypertension (especially if residual renal damage).

Prognosis

• Factors:
  • Age: Pediatric patients generally have a better prognosis than adults. Adults often have more severe renal involvement and higher rates of ESRD.
  • Severity of Renal Involvement: This is the most significant prognostic factor. Nephrotic-range proteinuria, impaired renal function at presentation, and crescentic glomerulonephritis on biopsy are associated with a higher risk of progression to CKD/ESRD.
  • GI Involvement: Severe acute GI complications (e.g., bowel perforation) can be life-threatening but generally do not impact long-term renal prognosis.
  • Recurrence: Recurrent episodes typically do not worsen long-term renal outcomes unless each recurrence involves severe renal disease.
• Survival: Excellent for the vast majority of children; mortality is rare (typically <1%) and usually due to severe GI or renal complications. Adults have a slightly higher mortality rate, usually related to severe renal or systemic complications.
• Quality of Life: Most patients recover completely with no long-term sequelae. However, those with persistent renal involvement or who develop CKD may experience a significant impact on their quality of life, requiring ongoing medical management and potentially dialysis or transplantation.

Prevention

• Primary: Currently, there are no specific primary preventive measures for IgAV, as its exact etiology is not fully understood, and triggers are diverse.
• Secondary: Early diagnosis and appropriate management of significant renal involvement are crucial to prevent progression to chronic kidney disease. Regular follow-up for several years after the acute phase is recommended to detect late-onset renal complications.
• Tertiary: For patients who develop chronic kidney disease as a complication of IgAV, tertiary prevention focuses on managing CKD progression, controlling hypertension, and preventing further complications through lifestyle modifications and specialist care (nephrology).

Special Populations

• Pediatric: IgAV is most common in this age group. Children generally have a milder course than adults, though they are more prone to intussusception. Renal involvement in children requires careful and prolonged monitoring.
• Geriatric: IgAV is rare in the elderly. When it occurs, it often presents with atypical skin lesions, a higher incidence and severity of renal disease, and potentially a higher mortality rate compared to children. The differential diagnosis in this age group is broader, and a skin biopsy is almost always warranted.
• Pregnancy: IgAV during pregnancy is rare. If active disease is present, it can be associated with adverse pregnancy outcomes such as preterm birth, pre-eclampsia, and fetal growth restriction, especially if there is pre-existing or active renal involvement. Management involves close monitoring of maternal and fetal well-being, and careful consideration of medication risks (e.g., corticosteroids) versus disease activity. Nephrology consultation is essential for women with IgAV nephritis who become pregnant.
• Comorbidities:
  • Chronic Kidney Disease: Requires close collaboration with a nephrologist to manage IgAV-related nephritis and optimize kidney function.
  • Hypertension: Aggressively managed, especially if related to renal involvement, to prevent further kidney damage and cardiovascular complications.
  • Gastrointestinal Disorders: Careful differentiation from IgAV manifestations. Patients on NSAIDs or other nephrotoxic drugs may need discontinuation if IgAV is suspected.

Clinical Pearls

• Diagnostic:
  • The "Palpable" in Purpura: Always confirm the purpura is palpable; this distinguishes IgAV from thrombocytopenic purpura (which is non-palpable petechiae/ecchymoses).
  • Abdominal Pain Precedes Rash: Remember that severe abdominal pain can occur before the characteristic rash, leading to diagnostic confusion. A high index of suspicion is needed, especially in children.
  • Always Check Urine: Every patient with suspected IgAV must have a urinalysis to screen for renal involvement, even if asymptomatic.
  • Adult IgAV: Often more severe, atypical, and requires a skin biopsy for definitive diagnosis more frequently than in children.
• Treatment:
  • Not All Patients Need Steroids: Mild IgAV (skin and mild joint pain only) often resolves spontaneously with supportive care. Corticosteroids are reserved for significant symptoms (severe abdominal pain, severe arthritis) or organ involvement.
  • Steroids for Abdominal Pain: Corticosteroids are effective for severe abdominal pain and may reduce its duration, but do not reliably prevent renal disease.
  • Renal Protection: For significant proteinuria or declining renal function, consult nephrology and consider corticosteroids with or without immunosuppressants and ACE inhibitors/ARBs.
  • NSAID Caution: Avoid NSAIDs if there is any gastrointestinal or renal involvement due to potential exacerbation.
• Pitfalls:
  • Missing Renal Involvement: Failure to perform serial urinalysis can lead to delayed diagnosis of IgAV nephritis, potentially impacting long-term renal outcomes.
  • Misdiagnosing Abdominal Pain: Attributing severe abdominal pain solely to "vasculitis" without considering surgical emergencies like intussusception or bowel perforation.
  • Over-treatment with Steroids: Unnecessary use of systemic corticosteroids for mild disease can expose patients to side effects without significant clinical benefit.
  • Confusing with Other Vasculitides: Particularly in adults with atypical presentations, a skin biopsy is crucial to differentiate IgAV from other forms of vasculitis (e.g., cryoglobulinemic vasculitis, ANCA-associated vasculitis).

Recent Updates

• Guidelines: The EULAR/PRINTO/PRES (European League Against Rheumatism/Paediatric Rheumatology International Trials Organisation/Paediatric Rheumatology European Society) 2010 criteria for the classification of IgA vasculitis (Henoch-Schönlein purpura) remain widely used for research and clinical practice. More recent consensus statements have reinforced the use of "IgA Vasculitis" over "Henoch-Schönlein Purpura."
• Evidence:
  • Increasing evidence suggests that early corticosteroids do not prevent IgAV nephritis. Their use is primarily for symptomatic relief of severe joint or abdominal pain.
  • The role of rituximab and other biologics (e.g., TNF-alpha inhibitors) is being explored for severe, refractory IgAV, particularly with progressive renal involvement, with promising but limited data.
  • Updated understanding of IgA glycosylation abnormalities continues to inform research into novel therapeutic targets.
• Controversies:
  • The optimal management of moderate IgAV nephritis (e.g., isolated persistent proteinuria without severe GFR decline) remains a subject of debate regarding the necessity and type of immunosuppression.
  • Long-term surveillance protocols for renal outcomes, especially in children, vary between institutions and countries.
  • The exact role of intravenous immunoglobulin (IVIG) in severe IgAV (especially with severe GI or renal involvement) remains controversial, with inconsistent evidence for its efficacy.

Key References

• Guidelines:
  • Ozen S, Pistorio V, et al. EULAR/PRINTO/PRES criteria for Henoch-Schönlein purpura. Ann Rheum Dis. 2010;69(5):798-801.
  • KDIGO (Kidney Disease: Improving Global Outcomes) Clinical Practice Guideline for Glomerulonephritis (relevant sections on IgA Vasculitis nephritis).
• Studies:
  • Weiss PF, Pollack R, et al. Renal outcomes in childhood IgA vasculitis (Henoch-Schönlein purpura). J Pediatr. 2010;157(5):810-815.e1.
  • Chartapisak W, Hongeng S, et al. The effectiveness of corticosteroids in IgA vasculitis (Henoch-Schönlein Purpura): A systematic review and meta-analysis. Indian J Pediatr. 2021;88(2):162-168.
• Reviews:
  • Reamy BV, Williams PM, Lindsay TJ. Henoch-Schönlein Purpura. Am Fam Physician. 2009;80(7):697-704.
  • Yang YH, Yu HH, et al. Henoch-Schönlein purpura: A review of pathophysiology and management. Curr Opin Rheumatol. 2014;26(1):3-9.
  • Dedeoglu F, Kim S. Clinical manifestations and diagnosis of IgA vasculitis (Henoch-Schönlein purpura). UpToDate. (Accessed via subscription, regularly updated).
  • Liew WK, et al. Henoch-Schönlein purpura in children: a review of treatment and prognosis. Int J Rheum Dis. 2019;22(Suppl 1):71-78.