Question: what are the causes of loss of smell?
Answer: Anosmia Causes Nasal congestion from a cold, allergy, sinus infection, or poor air quality is the most common cause of anosmia. Other anosmia causes include: Nasal polyps -- small noncancerous growths in the nose and sinuses that block the nasal passage. Injury to the nose and smell nerves from surgery or head trauma.