Acute Generalized Exanthematous Pustulosis in a Neonate Following Hepatitis B Vaccination: A Case Report.

Acute generalized exanthematous pustulosis (AGEP) is a rare severe cutaneous adverse reaction in neonates and is most commonly drug-induced. Vaccine-associated cases are uncommon in this age group. We report a term male neonate who developed clusters of non-follicular pustules on erythematous plaques approximately 6 hours after receiving a birth dose of hepatitis B vaccine. The infant remained clinically stable, without fever or systemic involvement, and had no exposure to concomitant medications. The rapid onset following a single exposure, characteristic morphology, and prompt resolution were highly suggestive of AGEP. Laboratory investigations and skin biopsy were not performed due to rapid clinical improvement. Infectious etiologies and transient neonatal pustular dermatoses were considered less likely based on the clinical course. Patch testing with the same vaccine lot was positive, supporting a type IV hypersensitivity mechanism. The eruption resolved almost completely within 48 hours with topical hydrocortisone, without complications or recurrence.