A patient on long-term decongestant nasal drops (oxymetazoline) for 3 months presents with rebound nasal congestion that has become dependent on the drops. The pathophysiological mechanism of rhinitis medicamentosa involves:
- A Downregulation/desensitization of alpha-2 adrenergic receptors and rebound vasodilation; also direct toxic effect on mucosal epithelium ✓
- B Upregulation of alpha-1 adrenergic receptors causing permanent vasoconstriction
- C IgE-mediated mast cell degranulation due to hapten formation
- D Sympathetic denervation of nasal blood vessels
Explanation
Rhinitis medicamentosa from prolonged alpha-adrenergic decongestant use (topical sympathomimetics like oxymetazoline/xylometazoline) involves: (1) tachyphylaxis — downregulation and desensitization of alpha-adrenergic receptors on nasal vascular smooth muscle, requiring increasing doses for the same effect; (2) rebound vasodilation between doses as drug wears off; (3) direct toxic effect on the nasal mucosa — mucosal edema, reduced mucociliary clearance, and goblet cell hyperplasia with continued use. Treatment involves gradual weaning, switching to intranasal saline, and often intranasal corticosteroids. The condition is not immune-mediated (no IgE mechanism).
Reference: Dhingra Diseases of Ear, Nose and Throat, 7th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.