Acute generalized exanthematous pustulosis (AGEP) is a febrile, pustular eruption that has been reported in all ages. Three weeks following oral terbinafine use, a 64-year-old male patient was admitted to the hospital for diffuse, nearly confluent erythematous plaques and desquamation, fevers, chills, and ulcer formation on his lower mucosal lip and tongue. Ten days prior to presentation, he was evaluated and discharged with a prednisone 60 mg taper for suspected erythema multiforme. Terbinafine was discontinued and the patient was monitored for systemic involvement. Recognition of subtle pustules on a background of EM-like lesions may facilitate the timely diagnosis and appropriate treatment of AGEP.