Difficulty with smell is one of the most troublesome symptoms for patients. Every year, approximately 2 million people in the United States are evaluated for smell and taste disorders. Mild cases involve partial loss while more severe cases can involve complete loss or distortions. Our sense of taste is intimately associated with smell, with up to 80% of taste sensation being enhanced by smell input. Therefore, loss of taste is often associated with loss of smell.
Olfactory nerve receptors are found in an area high up in the nose and connect directly to the brain. Taste cells are located in taste buds and receptors on the tongue and hard palate and relay information to nearby nerve fibers which subsequently send information to the brain.
Olfactory disorders can be classified as conductive or sensorineural. In some cases, a combination of the two types is present. Conductive disorders occur from loss of airflow, due to severely deviated nasal septum, turbinate hypertrophy, sinusitis, nasal polyps, and tumors. Conductive disorders are typically treatable with medications, surgery, or both. Sensorineural disorders occur from damage to the olfactory nerves themselves, typically following viral upper respiratory tract infections or head injuries, or from neurological disorders. Sensorineural losses are typically not treatable, and time will tell whether improvement is to occur. Losses of smell and taste caused by specific medications will typically resolve once the medication is stopped.
If you are experiencing difficulty with smell or taste, a thorough evaluation can help determine how to best treat your symptoms.