Levofloxacin-associated leukocytoclastic vasculitis with bullous lesions in a man treated for a diabetic foot infection

Levofloxacin and other fluoroquinolones are widely used antibiotics, though they can cause rare immune-mediated adverse events. We report a man in his late 50 s with long-standing type 2 diabetes mellitus and a new plantar foot wound who was prescribed oral levofloxacin for presumed soft-tissue infection. Within 48–72 hours of starting levofloxacin, he developed rapidly progressive palpable purpura that began on the upper extremities and spread to the lower extremities up to the thighs, with intense pruritus, migratory arthralgias, and bullous lesions on the distal lower extremities and right upper extremity. He had no mucosal involvement and no pulmonary or gastrointestinal symptoms. Dermatologic evaluation favored small-vessel vasculitis; systemic corticosteroids were initiated and the patient was transferred for further management. Skin biopsy demonstrated leukocytoclastic vasculitis with leukocytoclasis and fibrinoid necrosis of superficial dermal vessels. Direct immunofluorescence showed perivascular IgG and C3 without IgA deposition. Workup revealed elevated inflammatory markers, elevated serum IgA, positive p-ANCA with negative MPO and PR3, probable mixed cryoglobulins, and mild hematuria and proteinuria without casts; nephrology assessed low likelihood of clinically significant renal vasculitis. Levofloxacin was discontinued and a short corticosteroid taper was completed, with steady improvement of rash and stable renal function. This case highlights the recognition and evaluation of suspected fluoroquinolone-associated cutaneous small-vessel vasculitis and the importance of early biopsy of fresh lesions when IgA vasculitis is considered.