Hello, I went through your query, most common cause of anosmia include Nasal blockage from a cold, allergy, sinus infection, or poor air quality. Other anosmia causes include: Nasal polyps -- small noncancerous growths in the nose and sinuses that block the nasal passage. Other cause include some head injury... Supportive measures are enough for minor cold issues,, other causes needs to treated promptly. Please consult ENT specialist.