Topical antibiotic ointments are widely prescribed for infection prophylaxis after surgery and trauma, yet they are an important cause of allergic contact dermatitis. Autoeczematization, or id reaction, refers to secondary eczematous eruptions that arise at sites distant from a primary localized inflammatory focus. We report a 42-year-old man who developed generalized exudative erythematous papules after application of Baramycin® (bacitracin and fradiomycin sulfate) ointment to an erosion on his right lower leg treated for cellulitis. Despite improvement of systemic inflammatory markers, well-demarcated erythema confined to the area of ointment and dressing use, accompanied by widespread papules on the trunk, face, and extremities, persisted. Delayed patch testing could have been performed after clinical improvement, but the patient was lost to follow-up, and the clinical course strongly suggested allergic contact dermatitis with secondary autoeczematization. Discontinuation of Baramycin® and initiation of topical clobetasol propionate led to the gradual resolution of the primary lesion and rapid improvement of distant eruptions. This case underscores the need to consider autoeczematization in patients presenting with diffuse eczematous eruptions following the use of topical antibiotics.