The most common causes of olfactory disorders are nasal and sinus diseases. Allergic rhinitis, Nasal polyps, sinusitis, severe nasal bone and cartilage curvatures, nasal traumas, nasal concha enlargement, adenoids in children are common causes of nasal-related olfactory disorders. Apart from this, upper respiratory tract viral infections and head traumas are among the most common causes of olfactory disorders.

 

Source: http://www.kbb.org.tr