Iatrogenic Cushing’s syndrome associated with treatment of allergic rhinitis

Iatrogenic Cushing’s syndrome (CS) secondary to intranasal steroid use, although rare, poses significant diagnostic challenges—especially in adults. We present the case of a 40-year-old male who developed CS with hypothalamic-pituitary-adrenal (HPA) axis suppression following prolonged misuse of a dexamethasone nasal spray for allergic rhinitis. His symptoms resolved after discontinuation of the steroid and gradual hydrocortisone tapering. This case underscores the risk of systemic absorption from high-potency steroids such as dexamethasone, even when administered via non-oral routes. While intranasal steroids are considered safe at standard doses, prolonged misuse—particularly of high-potency formulations—may lead to systemic absorption.