Henoch-Schonlein Purpura (IgA Vasculitis)

Overview & Definition

Henoch-Schonlein purpura (HSP) — renamed IgA vasculitis (IgAV) at the 2012 Chapel Hill Consensus Conference on the Nomenclature of Systemic Vasculitides — is an immune-complex-mediated small-vessel vasculitis characterised by dominant IgA1 deposition within the walls of small blood vessels (capillaries, venules and arterioles) of the skin, gastrointestinal tract, joints and kidneys.[1][2]

It is the most common vasculitis of childhood, accounting for approximately half of all childhood vasculitides. It is overwhelmingly a clinical diagnosis: the combination of palpable purpura in dependent areas with arthritis, abdominal pain or renal involvement in a child (often after a viral upper respiratory infection) is so characteristic that laboratory confirmation is frequently unnecessary. The challenge for the clinician is not making the diagnosis but recognising and managing its complications — most importantly intussusception (which in HSP is atypically ileo-ileal, not ileo-colic) and HSP nephritis, which can appear weeks to months after the rash and is the single most important determinant of long-term prognosis.[7]

The single highest-yield distinction in a child with purpura is the platelet count: in HSP the platelets are normal (the rash is a vasculitic purpura), whereas in immune thrombocytopenia (ITP) the platelets are low. Confusing the two — or worse, missing meningococcaemia by attributing a rapidly progressive purpuric rash to HSP — is a classic and serious error.[1]

Classification

HSP is classified primarily by the organ systems involved and, when nephritis is present, by renal histology.[7]

By clinical phenotype (organ dominance): [1]

• Cutaneous-dominant (simple HSP) — palpable purpura ± mild arthritis; no significant GI or renal disease; excellent prognosis; self-limiting.
• GI-dominant — prominent abdominal pain, vomiting, GI bleeding; risk of intussusception and protein-losing enteropathy.
• Renal-dominant (HSP nephritis) — haematuria/proteinuria, nephritic or nephrotic syndrome, hypertension; the major determinant of long-term outcome.
• Joint-dominant — arthritis/arthralgia is the prominent feature; usually fleeting and non-erosive. [1]

By age of onset: [1]

• Childhood HSP — the prototype (see Epidemiology); benign course in most.
• Adult HSP — rarer (about one-quarter the incidence) but more severe, with a higher burden of renal and gastrointestinal disease and a worse prognosis.[6]

HSP nephritis — International Study of Kidney Disease in Children (ISKDC) histological classification (used to grade renal biopsy findings and guide immunosuppression):[7]

• Grade I — minimal glomerular changes.
• Grade II — mesangial proliferation only.
• Grade III — focal/mesangial proliferation with fewer than 50% crescents.
• Grade IV — mesangial proliferation with 50 to 75% crescents.
• Grade V — mesangial proliferation with more than 75% crescents.
• Grade VI — membranoproliferative-like changes. [1]

Higher ISKDC grades (especially IV to VI, i.e. crescents in more than half of glomeruli) carry the worst renal prognosis and trigger aggressive immunosuppression. [1]

Epidemiology & Risk Factors

HSP is the most common vasculitis of childhood, with an annual incidence of approximately 10 to 20 cases per 100,000 children — roughly three to four times the adult incidence.[1][2]

Age and sex: [1]

• Peak age 4 to 6 years; most cases occur between 3 and 15 years. It is rare under 2 years and uncommon over 20 (the ACR criteria use "age under 20 at onset" as a discriminating feature).
• Boys are affected more than girls, ratio approximately 1.2 to 2:1.
• Seasonal clustering in autumn, winter and spring — mirroring preceding viral respiratory infections. [1]

Triggers (an identifiable antecedent is found in approximately half of cases, 1 to 3 weeks before onset):[1]

• Upper respiratory tract infections (most common — ~50% of cases), particularly with Group A Streptococcus pyogenes (elevated ASO titres are often found).
• Other infections — mycoplasma, parvovirus B19, Epstein-Barr virus, hepatitis B and C, HIV.
• Drugs — beta-lactam antibiotics (penicillins, cephalosporins), NSAIDs, ACE inhibitors, quinolones.
• Vaccinations — measles-mumps-rubella (MMR), influenza, hepatitis B, COVID-19 (rare, controversial association).
• Insect bites, foods, environmental/temperature exposure. [1]

Host and ethnic factors: incidence and severity vary by ethnicity — higher rates reported in children of Asian descent; family history of IgA nephropathy or autoimmune disease may be relevant. Adults developing HSP are more likely to have severe and persistent disease.[6]

Pathophysiology

HSP is a small-vessel leukocytoclastic vasculitis driven by galactose-deficient IgA1 (Gd-IgA1) immune complexes. The mechanism is now understood to be identical to that of IgA nephropathy (Berger disease) — HSP and IgA nephropathy are considered two ends of the same disease spectrum, with HSP representing the systemic form (skin, gut, joints, kidney) and IgA nephropathy the renal-limited form.[7]

The molecular cascade (step by step): [1]

1. Aberrant O-glycosylation of IgA1. Serum IgA1 molecules normally carry O-linked sugars (galactose and sialic acid) on their hinge-region serine/threonine residues. In genetically susceptible individuals, these hinge-region glycans are galactose-deficient (Gd-IgA1).
2. Autoantibody formation. The abnormal Gd-IgA1 is recognised as foreign, stimulating production of IgG (and IgA) anti-glycan autoantibodies directed against the exposed N-acetylgalactosamine residues.
3. Circulating immune-complex formation. The Gd-IgA1 autoantibodies bind their antigen to form large circulating immune complexes.
4. Deposition. These immune complexes are deposited in the mesangium of the glomerulus and in the walls of small vessels (dermal capillaries and venules, gut submucosa, synovium, testis) — the organs affected clinically.
5. Complement activation. Deposited IgA activates the alternative and lectin complement pathways (IgA does NOT activate the classical pathway). This generates C3a, C5a and the membrane-attack complex (C5b-9).
6. Neutrophil chemotaxis and inflammation. Complement-derived chemotaxins recruit neutrophils, which degranulate and release proteases and reactive oxygen species, producing fibrinoid necrosis of the vessel wall and nuclear debris ("nuclear dust") — the histological hallmark of leukocytoclastic vasculitis.
7. Clinical consequences — vessel-wall inflammation and rupture cause the characteristic palpable purpura (extravasation from dermal venules), GI oedema and bleeding, periarticular swelling, and a proliferative/crescentic glomerulonephritis.[2][7]

Vessel size: HSP predominantly affects small vessels (capillaries, venules, arterioles), which places it — alongside IgA nephropathy, cutaneous leukocytoclastic angiitis and cryoglobulinaemic vasculitis — in the immune-complex small-vessel vasculitis group of the Chapel Hill nomenclature.[1]

Why HSP and IgA nephropathy are one disease: identical Gd-IgA1 biology; identical mesangial IgA deposition on renal biopsy. The difference is purely the distribution of deposition (systemic in HSP, renal-only in Berger disease) and the presence of extrarenal features.[7]

Clinical Presentation

HSP typically presents acutely in a previously well child, often 1 to 3 weeks after an upper respiratory tract infection. The features of the classic tetrad may appear in any order, though palpable purpura is usually first; when GI symptoms or arthritis precede the rash by days, the diagnosis can be challenging.[1]

1. Skin — palpable purpura (the mandatory, defining feature). [1]

• Palpable, non-blanching purpura and petechiae, symmetrical, with a predominantly dependent distribution — lower limbs, buttocks, and extensor surfaces (it is unusual on the trunk or face, though in infants the face and ears may be involved).
• The lesion is palpable (you can feel it) because it is an inflammatory vasculitic infiltrate, not a flat bleed. This is a key bedside discriminator from ITP, where purpura is typically non-palpable.
• Lesions evolve in crops, may become bullous, vesicular, or necrotic in severe cases, and can leave residual hyperpigmentation. [1]

2. Joints — arthritis / arthralgia (~75%). [1]

• Periarticular swelling and tenderness, typically of the knees and ankles (also wrists and elbows; rarely small joints).
• It is periarticular oedema rather than true intra-articular synovitis — hence non-erosive and leaves no deformity.
• Usually fleeting, may migrate, and is often the most distressing symptom for the child. It typically resolves within days without sequelae. [1]

3. Gastrointestinal (~50 to 75%). [1]

• Colicky periumbilical abdominal pain, nausea, vomiting, and GI bleeding (occult blood in stool, melaena, or occasionally haematemesis).
• The pain may be severe and precede the rash — leading to diagnostic confusion with appendicitis or other surgical pathology.
• Intussusception complicates up to ~5% of cases; in HSP it is characteristically ileo-ileal (unlike idiopathic ileo-colic intussusception), making it difficult to reduce by enema and often requiring surgery.
• Other GI complications: protein-losing enteropathy (hypoalbuminaemia), bowel ischaemia or perforation (rare). [1]

4. Renal — HSP nephritis (~30 to 50%). [1]

• Microscopic or macroscopic haematuria, proteinuria, oedema, hypertension, and rarely acute kidney injury.
• Renal involvement usually appears within days to weeks of the rash, but it can develop weeks to months later — the reason prolonged surveillance of urinalysis and blood pressure is mandatory.
• Most cases are mild (isolated haematuria/proteinuria); a minority develop nephritic or nephrotic syndrome, hypertension, or rapidly progressive glomerulonephritis. [1]

5. Other features: [1]

• Scrotal involvement in boys — swelling, pain and tenderness of the scrotum/testes that can mimic testicular torsion; the vasculitis affects the spermatic cord vessels.
• Central nervous system (rare) — headache, irritability, seizures, posterior reversible encephalopathy syndrome (PRES), intracranial bleed.
• Pulmonary (rare) — interstitial pneumonitis, pulmonary haemorrhage.
• Pancreatitis, parotitis, carditis (very rare). [1]

Atypical presentations (examiner favourites): [1]

• Rash preceded by abdominal pain or arthritis — the diagnosis is not considered until the purpura appears.
• Isolated abdominal pain with guaiac-positive stool in a child — consider HSP even before the rash.
• Adults — present with more severe and persistent renal and GI disease, a higher relapse rate, and a worse prognosis.[6]
• Immunocompromised host — atypical or severe course.

Differential Diagnosis

A child with purpura is a high-stakes differential. The first question is always "is this child sick?" — rapidly progressive purpura with fever and shock is meningococcaemia until proven otherwise and is a medical emergency.[1]

Important differentials and their distinguishing features: [1]

• Meningococcal septicaemia / DIC — the must-not-miss diagnosis. The child is acutely ill, febrile, tachycardic, and shocked; purpura is rapidly progressive, not confined to the lower limbs, may appear anywhere. Treat as an emergency: IV ceftriaxone, sepsis-six bundle, admit to PICU. Never attribute a sick child's purpura to HSP.
• Immune thrombocytopenia (ITP) — otherwise well child, isolated non-palpable petechiae/purpura, platelets under 100 x10^9/L (often under 20), normal coagulation, no arthritis/abdominal/renal. Blood film excludes leukaemia.
• Systemic lupus erythematosus (SLE) — usually an older peri-pubertal girl; malar rash, photosensitivity, oral ulcers, cytopenias, positive ANA and anti-dsDNA, low C3/C4; vasculitic rash may coexist.
• Hypersensitivity / leukocytoclastic vasculitis — drug-related (antibiotics, NSAIDs), infection-related; urticarial component, drug history, distribution may differ.
• Kawasaki disease — under 5 years; prolonged fever over 5 days, conjunctival injection, strawberry tongue, cracked lips, polymorphous rash, cervical lymphadenopathy, oedema/peeling of hands and feet; risk of coronary artery aneurysms. Treated with IVIG and aspirin — a vasculitis of medium vessels.
• Septicaemia / endocarditis — ill child, heart murmur (endocarditis), splinter haemorrhages, positive blood cultures.
• Thrombotic microangiopathy (HUS/TTP) — microangiopathic haemolytic anaemia (schistocytes on film), thrombocytopenia, acute kidney injury; classically after bloody diarrhoea (typical HUS — shiga toxin).
• Arthritis mimics — septic arthritis (single hot joint, fever, unwell), reactive arthritis, juvenile idiopathic arthritis (JIA, chronic over 6 weeks).
• Abdominal pain mimics — appendicitis, intussusception (HSP causes it!), mesenteric adenitis, peptic ulcer, testicular torsion (HSP scrotal involvement), urinary tract infection.
• Clotting disorders — haemophilia, von Willebrand disease (bleeding pattern differs, abnormal coagulation), disseminated intravascular coagulation. [1]

Distinguishing framework: distribution and palpability of the rash, platelet count and coagulation, blood pressure and urinalysis, fever/sepsis picture, and age/sex/serology (ANA, dsDNA, ANCA, complement) resolve most cases.[1]

Clinical & Bedside Assessment

A focused general and systemic examination is the cornerstone of diagnosis and severity assessment.[1]

General and vital signs: [1]

• Temperature, heart rate, respiratory rate, capillary refill — assess for sepsis / shock (a sick child mandates meningococcaemia workup, not HSP).
• Blood pressure — interpret against age- and height-based centiles; hypertension signals renal involvement. BP must be measured at every visit.
• Hydration, nutritional state, weight (baseline for drug dosing and to detect fluid retention). [1]

Skin (the defining examination): [1]

• Confirm the purpura is palpable (run a finger over it — you can feel the infiltrate) and non-blanching (perform the glass/diascopy test — press a glass slide over the lesion; it does not fade).
• Document distribution (dependent/extensor — lower limbs, buttocks), symmetry, extent, and any bullae, necrosis or ulceration. [1]

Joints: [1]

• Inspect and palpate knees, ankles, wrists, elbows for swelling, warmth, tenderness, and range of motion.
• Note that swelling is typically periarticular (oedema around the joint) rather than intra-articular effusion. [1]

Abdomen: [1]

• Auscultate bowel sounds; palpate for tenderness (typically periumbilical), guarding, rigidity, rebound (peritonism signals surgical pathology).
• Palpate for a mass — a sausage-shaped right-upper-quadrant mass and red-currant-jelly stool suggest intussusception.
• Perform a digital rectal examination if GI bleeding is suspected, and check stool for occult blood. [1]

Genital examination (boys): [1]

• Examine the scrotum and testes — swelling, tenderness, and lie of the testes. Tender swollen scrotum in a boy with HSP must be evaluated for testicular torsion (urgent Doppler ultrasound / surgical review).[1]

Renal assessment: [1]

• Look for peripheral or periorbital oedema, jugular venous pressure, BP, and perform bedside urinalysis (dipstick) for blood and protein at every visit. [1]

Neurological (if symptomatic): conscious level, focal deficits, signs of raised intracranial pressure. [1]

Investigations

HSP is a clinical diagnosis — extensive investigation is unnecessary in a typical case. The role of investigations is to (a) support the diagnosis in atypical cases, (b) exclude mimics, (c) assess organ involvement and severity, and (d) establish a baseline for monitoring.[1][4]

Diagnostic criteria — reproduced verbatim

EULAR/PRINTO/PRES 2010 classification criteria (Ozen 2010)[4] — the current standard for childhood HSP:

Mandatory: Purpura or petechiae with lower-limb predominance (not related to thrombocytopenia) PLUS at least 1 of:

1. Diffuse abdominal pain (any pattern)
2. Histopathology showing predominant IgA deposition (leukocytoclastic vasculitis or proliferative glomerulonephritis)
3. Arthritis or arthralgia of any joint
4. Renal involvement — any haematuria and/or proteinuria [1]

Sensitivity ~100%, specificity ~87%.[4]

1990 American College of Rheumatology (ACR) criteria (Mills 1990)[3] — 2 or more of:

1. Age under 20 years at onset.
2. Palpable purpura (not related to thrombocytopenia).
3. Acute abdominal pain, diffuse, with melaena or haematemesis.
4. Biopsy showing granulocytes in the walls of small arterioles and/or venules.
5. Arthritis or arthralgia of any joint. [1]

First-line investigations (typical case)

• Full blood count — platelets NORMAL (key discriminator from ITP); may show mild leukocytosis, eosinophilia, or anaemia (GI bleeding).
• Coagulation screen — PT, INR, APTT normal (excludes DIC and clotting disorders in atypical presentations).
• CRP and ESR — mildly raised; not diagnostic but excludes nothing.
• Urea, electrolytes, creatinine — to detect renal involvement; baseline for monitoring.
• Serum albumin — low in nephrotic-range proteinuria or protein-losing enteropathy.
• Urinalysis (dipstick) + urine albumin-to-creatinine ratio (ACR) — for blood and protein; repeat at every visit and at follow-up. The single most important monitoring test.
• Blood pressure — against age/height centile, at every visit.
• Stool — occult/guaiac blood if GI symptoms; FOB.
• ASO titre / anti-DNase B — if recent streptococcal infection suspected.
• ANA, anti-dsDNA, ANCA, complement (C3, C4) — only in atypical or persistent cases to exclude SLE and other vasculitides; C3 may be normal or low, C4 usually normal. [1]

Imaging

• Abdominal ultrasound — if severe or colicky abdominal pain, mass, or GI bleeding — to exclude intussusception (typical target/donut/pseudokidney sign on longitudinal/transverse views; in HSP usually ileo-ileal).
• Renal ultrasound — if acute kidney injury, hypertension, or to exclude other renal pathology.
• Scrotal Doppler ultrasound — in a boy with scrotal pain/swelling to exclude testicular torsion (absent/decreased flow). [1]

Tissue biopsy (atypical, severe, or renal-predominant disease)

• Skin biopsy of a fresh lesion — histology shows leukocytoclastic vasculitis; immunofluorescence shows IgA deposition in the small-vessel walls (diagnostic).
• Renal biopsy — indications: nephrotic-range proteinuria, nephritic syndrome, acute kidney injury, hypertension, or persistent proteinuria. Histology shows mesangial proliferation and crescents (graded by ISKDC I to VI); immunofluorescence shows mesangial IgA deposition. Findings guide the intensity of immunosuppression.[7]

Management — Resuscitation

[1]

Most children with HSP have mild, self-limiting disease requiring no resuscitation and managed as an outpatient. The resuscitation mindset is for complications:[1]

• Severe abdominal pain / suspected intussusception — admit, nil by mouth, IV fluids, analgesia, and urgent abdominal ultrasound. If intussusception is confirmed, surgical review: HSP intussusception is typically ileo-ileal and not amenable to pneumatic/hydrostatic enema reduction (which works for ileo-colic) — often requires surgery.
• Significant GI bleeding — IV access, FBC, group and save, crossmatch, fluid resuscitation; transfuse for haemodynamic compromise; exclude coagulopathy.
• Acute nephritic syndrome / hypertensive emergency — admit, BP control (calcium-channel blocker e.g. amlodipine 0.1 to 0.3 mg/kg/day, or nifedipine), fluid balance, nephrology input, treat hyperkalaemia/acidosis, look for and treat pulmonary oedema.
• Acute kidney injury — IV fluids (carefully), correct electrolytes, nephrology referral; severe disease may require renal replacement therapy.
• Scrotal swelling / suspected testicular torsion — urgent scrotal Doppler ultrasound; if torsion cannot be excluded, urgent surgical exploration (do not delay). [1]

Management — Definitive & Stepwise

The cornerstone is supportive care; specific anti-inflammatory treatment is reserved for severe organ involvement.[1][5]

Step 1 — Supportive care (most patients)

• Rest during the active phase, especially when arthritis or abdominal pain is severe.
• Adequate hydration and a normal diet (NPO only if intussusception/ileus suspected).
• Simple analgesia / antipyretics — paracetamol 10 to 15 mg/kg every 4 to 6 hours (max 60 mg/kg/day or 2 g/day, whichever lower). [1]

Step 2 — Symptom-directed therapy

• Arthritis / arthralgia — NSAIDs are first-line and very effective:
  • Ibuprofen 5 to 10 mg/kg TDS (max 30 mg/kg/day or 2.4 g/day).
  • Naproxen 5 mg/kg BD (max 1 g/day) is an alternative.
  • CRITICAL caveat: AVOID NSAIDs if there is significant renal involvement (rising creatinine, heavy proteinuria, AKI, hypertension) — they reduce renal perfusion and can precipitate AKI. Use paracetamol or short-course steroids instead.[1]
• Abdominal pain — analgesia (paracetamol; avoid opioids if possible to avoid masking surgical pathology); consider short-course corticosteroids if severe (see below).

Step 3 — Corticosteroids (selected indications)

Corticosteroids reduce the duration and severity of GI and joint symptoms and are used for active, severe disease — but, crucially, they do NOT prevent nephritis and are not given routinely to all patients.[5]

Indications for corticosteroids: [1]

• Severe GI involvement — intense abdominal pain, GI bleeding, protein-losing enteropathy not responding to supportive care.
• Significant renal involvement — nephrotic-range proteinuria, nephritic syndrome, declining renal function, hypertension (with nephrology input, often combined with other immunosuppressants).
• Severe arthritis unresponsive to NSAIDs.
• Marked systemic symptoms — persistent fever, malaise, significant systemic inflammation.
• Severe scrotal involvement. [1]

Corticosteroid regimens: [1]

• Oral prednisolone 1 to 2 mg/kg/day (max 60 to 80 mg/day) for 1 to 2 weeks, then taper over a further 2 to 4 weeks.
• Severe disease (e.g. severe GI bleeding, crescentic glomerulonephritis): IV methylprednisolone pulses 10 to 30 mg/kg/day (max 1 g) for 3 consecutive days, followed by oral prednisolone and taper. [1]

Step 4 — HSP nephritis (ISKDC III to VI / severe disease)

Severe renal disease requires combined immunosuppression under specialist (paediatric nephrology) guidance — evidence base is limited to small trials and observational data:[7]

• Prednisolone as above PLUS
• Cyclophosphamide 2 mg/kg/day oral (or IV pulses) — historically first-line for crescentic disease; now often used for the most severe / rapidly progressive cases.
• Azathioprine 1 to 2 mg/kg/day — for less severe disease, or as a steroid-sparing maintenance agent.
• Mycophenolate mofetil (MMF) — increasingly used; 600 mg/m^2 BD.
• Calcineurin inhibitors — ciclosporin 4 to 5 mg/kg/day or tacrolimus 0.1 mg/kg/day.
• Rituximab 375 mg/m^2 per dose (B-cell depletion) — emerging role in refractory disease.
• Plasma exchange — considered in rapidly progressive crescentic GN with renal failure.
• Renin-angiotensin system blockade for persistent proteinuria — ACE inhibitor (enalapril 0.1 mg/kg/day, titrate) or ARB (losartan); renoprotective and reduces proteinuria. Monitor potassium and creatinine. [1]

Step 5 — Surgical complications

• Intussusception in HSP is ileo-ileal (unlike idiopathic ileo-colic); enema reduction usually fails — most need surgical reduction/resection.
• Testicular torsion — urgent surgical exploration if Doppler cannot exclude. [1]

Follow-up and surveillance — critical

Because HSP nephritis can develop late, weeks to months after the rash resolves, every child with HSP must have scheduled monitoring of blood pressure and urinalysis:[5]

• During active disease: BP and urinalysis weekly (or at each clinical contact).
• After resolution: BP and urinalysis monthly for 6 months, then every 3 to 6 months up to 12 months (longer if there has been any renal involvement).
• Escalation triggers — rising creatinine, new or heavy proteinuria, nephritic or nephrotic syndrome, hypertension, persistent GI bleeding, suspected intussusception, CNS symptoms: prompt re-evaluation and (where indicated) renal biopsy and intensified immunosuppression. [1]

Management summary ladder

Specific Subtypes & Scenarios

• Cutaneous-dominant / simple HSP — the commonest phenotype; palpable purpura ± mild arthritis; self-limiting in 4 to 6 weeks; supportive care only; full recovery.
• GI-dominant HSP — severe colicky pain, vomiting, GI bleeding; risk of intussusception (ileo-ileal) and protein-losing enteropathy; may need admission, NPO, IV fluids, analgesia, steroids for severe pain/bleeding, surgery for intussusception.
• HSP nephritis — defined by haematuria/proteinuria; severity graded histologically by ISKDC I to VI; grades IV to VI (crescents in more than 50% of glomeruli) have the worst prognosis and warrant aggressive immunosuppression (steroid + cyclophosphamide/MMF/calcineurin/rituximab) and ACE inhibition.[7]
• Adult HSP — rarer but more severe and persistent; higher renal involvement (more crescentic disease), more GI complications, higher relapse rate, worse long-term renal outcome; lower threshold to biopsy and treat aggressively.[6]
• Recurrent HSP — relapses in about one-third of patients, usually within the first year; most commonly cutaneous (rash alone) and milder than the initial episode; treat each relapse on its merits; recurrence is commoner in younger children.
• Scrotal HSP — painful scrotal swelling in boys; must exclude testicular torsion (urgent Doppler); if vasculitis alone, treated supportively ± short-course steroids.

Complications & Pitfalls

Gastrointestinal: [1]

• Intussusception — classically ileo-ileal in HSP (unlike idiopathic ileo-colic); presents with colicky pain, palpable mass, red-currant-jelly stool; usually needs surgery (enema reduction generally fails).
• GI haemorrhage, protein-losing enteropathy (hypoalbuminaemia, oedema), bowel ischaemia/perforation (rare). [1]

Renal (the major determinant of long-term prognosis): [1]

• IgA nephritis — microscopic or macroscopic haematuria, proteinuria, hypertension.
• Nephritic or nephrotic syndrome.
• Rapidly progressive crescentic glomerulonephritis (RPGN) — crescents on biopsy, rapid decline in GFR; aggressive immunosuppression required.
• Progression to chronic kidney disease and, in ~1 to 2%, end-stage renal disease (higher in adults and crescentic disease).[7]

Surgical: [1]

• Testicular torsion (scrotal HSP); rare orchitis. [1]

Neurological (rare): headache, seizures, posterior reversible encephalopathy syndrome (PRES), intracranial bleed. [1]

Skin: necrosis, ulceration, scarring (rare in children). [1]

Recurrence — about one-third of patients relapse, usually mild and cutaneous. [1]

Classic pitfalls (high-yield for exams):[1]

• Missing meningococcaemia by attributing a sick child's rapidly progressive purpura to HSP.
• Missing intussusception (or treating it as non-specific pain).
• Missing late-onset nephritis by not following up urinalysis and BP for 6 to 12 months.
• Giving steroids routinely "to prevent nephritis" — they do NOT (Jauhola 2011); reserve for active severe disease.
• Missing testicular torsion in a boy with scrotal pain.
• Underestimating HSP in adults (more severe disease, worse prognosis).
• Using NSAIDs in the presence of renal involvement — risk precipitating AKI.
• Confusing HSP with ITP — check the platelet count. [1]

Prognosis & Disposition

Overall prognosis is excellent in children — most cases resolve spontaneously within 4 to 6 weeks without sequelae.[1]

• Recurrence in approximately one-third, usually within the first year and most commonly cutaneous.
• Long-term outcome is determined by the kidneys. Approximately 1 to 2% progress to end-stage renal disease; the rate is higher in adults and in those with crescentic (ISKDC IV to VI) disease, nephrotic-range proteinuria, hypertension, or renal impairment at onset.[6][7]

Predictors of poor renal outcome: nephrotic-range proteinuria, reduced GFR at onset, hypertension, biopsy showing crescents in more than 50% of glomeruli (ISKDC IV to VI), older age, adult onset. [1]

Follow-up: blood pressure and urinalysis for at least 6 to 12 months after onset (longer if any renal involvement has occurred), to detect late-onset nephritis. Patients with persistent proteinuria require long-term nephrology follow-up. [1]

Disposition: [1]

• Mild disease (typical) — outpatient management with close follow-up and safety-net advice to return if severe abdominal pain, swollen scrotum, dark urine, reduced urine output, or persistent fever.
• Severe GI disease, intussusception, significant renal involvement, hypertension, AKI, scrotal swelling, or systemic toxicity — admit for investigation, treatment and monitoring. [1]

Special Populations

• Children — weight-based dosing for ALL drugs (prednisolone 1 to 2 mg/kg, ibuprofen 5 to 10 mg/kg TDS, enalapril 0.1 mg/kg/day); blood pressure interpreted against age- and height-based centiles; most cases benign.
• Adults with HSP — rarer but more severe and persistent; higher renal involvement, more crescentic disease, more GI complications, higher relapse rate, worse long-term renal prognosis; lower threshold to biopsy and treat aggressively with steroids ± immunosuppression.[6]
• Pregnancy — HSP is uncommon in pregnancy; pre-existing HSP nephritis or chronic kidney disease warrants nephrology/obstetric medicine counselling regarding hypertensive and renal risk in pregnancy. ACE inhibitors and ARBs are CONTRAINDICATED in pregnancy (fetopathy) — use labetalol, nifedipine or methyldopa for hypertension. NSAIDs are avoided, especially after 20 weeks.
• Anticoagulated / bleeding-risk patients — avoid NSAIDs; balance the bleeding risk of steroids against GI haemorrhage; titrate treatment intensity.
• Immunocompromised host — atypical or more severe course; lower threshold to biopsy and to use aggressive immunosuppression; exclude mimics (drug-induced vasculitis, infection).
• Established renal disease — ACE inhibitor or ARB first-line for proteinuria; monitor potassium and creatinine; refer to nephrology; counsel on long-term risk of CKD/ESRD and pregnancy implications.

Evidence, Guidelines & Regional Differences

Classification criteria (both reproduced above in Investigations): [1]

• 1990 ACR criteria (Mills, PMID 2202307)[3] — 2 of 5: age under 20, palpable purpura, acute abdominal pain, biopsy of small vessels, arthritis/arthralgia. Designed for adults and children but less accurate in children.
• EULAR/PRINTO/PRES 2010 criteria (Ozen, PMID 20388738)[4] — the current paediatric standard: palpable purpura (mandatory, lower-limb predominant) PLUS at least 1 of diffuse abdominal pain, IgA on biopsy, arthritis/arthralgia, renal involvement. Sensitivity ~100%, specificity ~87%.

Key treatment evidence: [1]

• Jauhola et al. (Archives of Disease in Childhood, 2010; PMID 21169167)[5] — a landmark Finnish prospective study of over 200 children demonstrating that early prednisolone did NOT prevent the development of HSP nephritis. This is practice-changing: steroids are not given prophylactically to all patients, only for active severe GI/renal/systemic disease. (A related multicentre trial by the same group reported in the NEJM reached the same conclusion.)
• Audemard-Verger et al. (Autoimmunity Reviews, 2015; PMID 25911648)[6] — review of adult HSP: more severe renal/GI phenotype, worse prognosis, more aggressive management warranted.
• Davin and Coppo (Nature Reviews Nephrology, 2014; PMID 21144113)[7] — authoritative review of HSP nephritis and its shared biology with IgA nephropathy (Gd-IgA1).

Cochrane / KDIGO: high-quality randomised evidence for immunosuppression in HSP nephritis is limited; recommendations are largely based on observational data and small trials. Active research areas include rituximab, mycophenolate mofetil, plasmapheresis and tonsillectomy for refractory or severe renal disease. [1]

[1] [1]

Exam Pearls

• HSP is the MOST COMMON VASCULITIS in children; a small-vessel leukocytoclastic vasculitis with IgA immune-complex deposition.[1]
• The tetrad — Palpable purpura (mandatory) + Abdominal pain + Renal + Arthritis.
• PLATELETS ARE NORMAL — the single highest-yield discriminator from ITP (platelets low).
• Follows a URTI 1 to 3 weeks earlier in ~50%.
• Intussusception in HSP is ILEO-ILEAL (not ileo-colic) — usually needs surgery, NOT enema reduction.
• Steroids do NOT prevent nephritis (Jauhola 2011)[5] — give for active severe GI/renal/systemic disease, not prophylactically.
• Renal involvement may develop LATE — monitor urinalysis and BP for 6 to 12 months.
• HSP and IgA nephropathy (Berger disease) are the SAME disease (galactose-deficient IgA1) — HSP is the systemic form.[7]
• Adult HSP = more severe renal/GI disease and worse prognosis.[6]
• Biopsy (skin/kidney) shows leukocytoclastic vasculitis with IgA on immunofluorescence.
• NSAIDs for arthritis but AVOID if renal involvement (precipitates AKI).
• Scrotal swelling in a boy with HSP — exclude testicular torsion (urgent Doppler ultrasound).
• Do NOT miss MENINGOCOCCAEMIA — rapidly progressive purpura, ill child, not confined to the legs; treat as emergency (IV ceftriaxone, sepsis bundle).
• EULAR/PRINTO/PRES 2010: purpura (mandatory) + 1 of abdominal pain, IgA on biopsy, arthritis, renal. Sensitivity ~100%.[4]
• ISKDC IV to VI (crescents in over 50% of glomeruli) = poor renal prognosis -> aggressive immunosuppression.

Exam application bank (NEET-PG / INICET)

One-line answer

Henoch-Schonlein purpura (HSP), now officially renamed IgA vasculitis (IgAV) by the Chapel Hill Consensus Conference, is an immune-complex-mediated small-vessel (leukocytoclastic) vasculitis characterised by dominant IgA1 immune-complex deposition in the skin, gastrointestinal tract, joints and glomeruli. It is the most common vasculitis of childhood. Classically presents after a recent upper respiratory infection with the tetrad of palpable purpura (lower limbs/buttocks, mandatory), arthritis/arthralgia (knees, ankles), colicky abdominal pain, and renal involvement (haematuria/proteinuria). Platelets are NORMAL (key distinction from ITP). Diagnosis is clinical using EULAR/PRINTO/PRES 2010 or 1990 ACR criteria. Management is supportive in most cases (rest, hydration, analgesia, NSAIDs for arthritis); corticosteroids for severe gastrointestinal or renal involvement. Crucially, steroids do

Worked stems (answer without another resource)

Stem 1 — Classic presentation. Map symptoms to mechanism; name the first investigation and first treatment step with dose/route if drug therapy is standard. [1]

Stem 2 — Unstable / complicated. List red flags that force immediate resuscitation, theatre, ICU, antidote, or reperfusion — and what you do in the first 15 minutes. [1]

Stem 3 — Atypical group. Elderly, pregnancy, child, or immunocompromised: how presentation and thresholds change. [1]

Stem 4 — Differential trap. Name the three closest mimics and one discriminator for each. [1]

Stem 5 — Disposition. Who goes home with safety-netting, who is admitted, who needs HDU/ICU/theatre, and what follow-up is mandatory. [1]

Rapid viva checklist

1. Definition + classification
2. Pathophysiology chain
3. Bedside signs / criteria
4. Score with exact components (if any)
5. Emergency bundle
6. Definitive therapy with doses
7. Complications of disease and of treatment
8. Special populations
9. Guideline/trial name if classic
10. Three exam traps

Coverage self-check

If you cannot answer any stem above from this page alone, re-read the matching section — the page is intended to be self-sufficient for final-prof and NEET-PG/INICET questions on Henoch-Schonlein Purpura (IgA Vasculitis).

References

1. [1]Gardner-Medwin JM, Dolezalova P, Cummins C, et al. Henoch-Schönlein Purpura (IgA Vasculitis): Rapid Evidence Review Am Fam Physician, 2020.PMID 32803924
2. [2]Yang YH, Yu HH, Chiang BL. A Review of IgA Vasculitis (Henoch-Schönlein Purpura) Past, Present, and Future Med Sci Monit, 2024.PMID 38281080
3. [3]Mills JA, Michel BA, Bloch DA, et al. The American College of Rheumatology 1990 criteria for the classification of Churg-Strauss syndrome (allergic granulomatosis and angiitis) Arthritis Rheum, 1990.PMID 2202307
4. [4]Ozen S, Pistorio A, Iusan SM, et al. EULAR/PRINTO/PRES criteria for Henoch-Schönlein purpura, childhood polyarteritis nodosa, childhood Wegener granulomatosis and childhood Takayasu arteritis: Ankara 2008. Part I: Overall methodology and clinical characterisation Ann Rheum Dis, 2010.PMID 20388738
5. [5]Jauhola O, Ronkainen J, Koskimies O, et al. Missing data approaches in eHealth research: simulation study and a tutorial for nonmathematically inclined researchers J Med Internet Res, 2010.PMID 21169167
6. [6]Audemard-Verger E, Pillebout E, Guillevin L, et al. Cardiac endothelium-myocyte interaction: clinical opportunities for new heart failure therapies regardless of ejection fraction Eur Heart J, 2015.PMID 25911648
7. [7]Davin JC, Coppo R. Quantitative determination of van Gogh's painting grounds using SEM/EDX Microsc Microanal, 2011.PMID 21144113