An Unusual Timing of Amoxicillin-Induced IgA Vasculitis in an Elderly Patient.

Immunoglobulin A vasculitis is a small vessel vasculitis which is usually common in the pediatric group. It is rare in adult population but more severe than in children. Proposed triggers include infections, malignancy and medications. For most part, the association is made when immunoglobulin A vasculitis develops within two weeks after starting the implicated medication. A 66-year-old male who was treated with amoxicillin/clavulanate for presumed right fourth toe infection but returned to the emergency department 48 hours later with palpable purpura of lower limbs, arthralgia with swollen hands and colicky abdominal pain with nausea. Abdominal computed tomography (CT) scan showed mildly dilated small bowel. Skin biopsies showed leukocytoclastic vasculitis with IgA deposit on immunofluorescence. The patient was treated with a short course of steroid and the rash was significantly reduced during subsequent follow-up. Although amoxicillin/clavulanate is widely prescribed, clinicians need to be aware of this risk and immediately stop it if signs of drug-induced vasculitis develop.