Adult-Onset Henoch–Schönlein Purpura Triggered by Isotretinoin with Persistent Polyarthritis and Isolated Cutaneous-Gastrointestinal Involvement: A Case Report

Introduction

IgA vasculitis (Henoch–Schönlein purpura, HSP) is a small-vessel vasculitis predominantly affecting children, while adult-onset disease is less common and often more severe, particularly with renal involvement. Drug-induced cases are rare, with only isolated reports linking isotretinoin to IgAV. Case Presentation: A 30-year-old woman developed palpable purpura, abdominal pain, and symmetric polyarthritis three weeks after starting isotretinoin. Laboratory evaluation showed mild inflammation with negative autoimmune workup and normal renal function; repeated urinalysis remained normal. Isotretinoin was discontinued, and corticosteroid therapy led to resolution of cutaneous and gastrointestinal symptoms. However, persistent inflammatory polyarthritis beyond six weeks required initiation of methotrexate, with subsequent improvement. No renal involvement developed during follow-up.