Cutaneous lichenoid drug eruption (LDE) is a rare but increasingly common adverse drug reaction (ADR), often challenging to diagnose due to its clinical and histological resemblance to lichen planus (LP). We report the case of a 57-year-old man with a lichenoid eruption likely secondary to systemic antibiotics. He presented a widespread pruritic dermatosis, characterized by dark brown, lichenified plaques, particularly in the axillary folds. A punch biopsy revealed lamellar hyperkeratosis, mild acanthosis, vacuolization, and a moderate infiltrate of lymphocytes, histiocytes, and eosinophils in the superficial dermis, compatible with LDE. LDE is typically triggered by various medications, and its pathogenesis involves T-cell-mediated autoimmune damage to altered basal keratinocytes. Treatment involves discontinuing the offending drug, though recovery may take weeks to months. Corticosteroids, both topical and systemic, may be required in severe cases or when drug cessation is not feasible. This case emphasizes the importance of recognizing LDE, particularly in patients on multiple medications, to ensure prompt diagnosis and management.