Confirmation of Metformin-Induced Acute Generalized Exanthematous Pustulosis Through a Positive Dechallenge-Rechallenge Test: A Case Report and Review of Cutaneous Manifestations Associated With Metformin

This case report highlights a rare instance of acute generalized exanthematous pustulosis (AGEP) induced by metformin in a 45-year-old male with prediabetes. AGEP is a severe skin reaction characterized by the sudden appearance of pustules on inflamed skin, typically triggered by medications. The diagnosis was confirmed through a positive dechallenge-rechallenge test, where symptoms resolved upon discontinuation of metformin and recurred upon reintroduction. This case underscores the importance of recognizing dermatological reactions associated with metformin, despite their rarity, to prevent serious complications and ensure effective management.