HENOCH SCHONLEIN (ANAPHYLACTOID) PURPURA • Most common systemic vasculitis in children • 90% cases occur in the age group 3 to 10 years • Immune complex deposition causing small vessel vasculitis • Many cases of HSP follow a documented upper respiratory infection Characterized by the tetrad of • Palpable purpura (due to vasculitis, not due to thrombocytopenia) - occur in gravitydependent areas (lower extremities) or on pressure points (buttocks) • Polyarthralgia in the absence of arthritis (non-deforming, oligoarticular, involves large joints, migratory) • Gl symptoms (colicky abdominal pain, passage of blood and mucus per rectum, intussusception) - in 80% children • Mild glomerulonephritis (IgA deposition in the mesangium, microscopic hematuria) - in 50% children • Chronic renal disease develops in 1-2% of children with HSP • Approximately 8% of those with HSP nephritis go on to have end-stage renal disease • Myocardial involvement can occur in adults but is rare in children Laboratory features • ANCA negative • Leukocytoclastic vasculitis with IgA deposition in the small vessels in the skin, joints, gastrointestinal tract & kidney • Deposition of C3, fibrin, and IgM are also seen to a lesser extent • Elevated ESR • Normal platelet count • Normal complement levels Diagnosis, prognosis and treatment • No laboratory finding is diagnostic of HSP; The diagnosis of HSP is a clinical one • Treatment for mild and self-limited HSP is supportive • Steroids are most often used to treat significant gastrointestinal involvement or other lifethreatening manifestations • Predisone: useful in decreasing tissue edema, arthralgias, and abdominal discomfort; but does not alter overall prognosis nor prevent renal disease. • The prognosis is excellent ❖ Deposits of IgA are also found in the glomerular mesangium in a variety of systemic diseases, including chronic liver disease, Crohn's disease, gastrointestinal adenocarcinoma, chronic bronchiectasis, idiopathic interstitial pneumonia, dermatitis herpetiformis, mycosis fungoides, leprosy, ankylosing spondylitis, relapsing polychondritis, and Sjogren's syndrome.