Acute generalized exanthematous pustulosis (AGEP) is a rare, potentially severe cutaneous adverse reaction characterized by the rapid onset of numerous small, sterile pustules on edematous erythema, commonly accompanied by systemic symptoms such as high-grade fever and neutrophilic leukocytosis. AGEP is most frequently triggered by medications, especially antibiotics, though infections and other exposures can also be causative. We report the case of a previously healthy 27-year-old male patient who developed a febrile pustular eruption with systemic involvement. Initial symptoms included sore throat, malaise, and a progressing maculopapular rash evolving into pustular plaques. The patient had previously taken oral ibuprofen without any adverse reactions; therefore, a drug-related trigger was considered unlikely, and an infectious etiology was suspected. Diagnosis of definite AGEP was established through clinical evaluation, laboratory findings showing leukocytosis with neutrophilia, and histopathology revealing subcorneal neutrophilic pustules with dermal edema and eosinophilic infiltrate. This case underscores the importance of early recognition of AGEP in febrile pustular eruptions, even without clear drug exposure.