How is dx of HSP?

• Diagnosis often made on clinical presentation, especially in children, +/- skin biopsy • Skin biopsy shows leukocytoclastic vasculitis in postcapillary venules (small vessel disease) Immune complexes in vessel walls contain IgA deposition (the diagnostic feature of HSP) • Rule out streptococcal infection with an ASO or throat culture • It is also important to look for systemic disease: • Renal: Urinalysis with micro, BUN/Cr • Gastrointestinal: Stool guaiac • HSP in adults may be a manifestation of underlying malignancy – Natural History: most children completely recover from HSP Some develop progressive renal disease More common in adults Tx: supportive +/- prednisone.