What Causes Smell Loss?

Anosmia is the clinical term for smell loss. The Mayo Clinic reports that the condition can be either temporary or permanent, depending on the underlying cause. A number of factors can lead to smell loss.

Congestion

• The National Institutes of Health indicates that nasal congestion is the most common cause of anosmia. Congestion can be caused by allergies (such as hay fever), sinus infections, flu, colds and non-allergic rhinitis.

Obstructions

• Obstructions in the nasal passages can also cause smell loss by obstructing airflow. The Mayo Clinic cites the following as common nasal obstructions: tumors, nasal polyps and bony protrusions.

Age

• Aging can lead to the breakdown of the nerves in the olfactory (smell) receptors that transmit information from the nose to the brain.

Brain Damage

• Damage to the brain from trauma, surgery, tumors and aneurysms can all impact or destroy the ability to smell.

Diseases

• Diseases, particularly degenerative diseases such as Parkinson's, Alzheimer's and Huntington's that affect the brain or nervous system, can cause the loss of smell.

Medical Treatments

• The Mayo Clinic reports that some medical treatments such as radiation therapy or medications such as nifedipine can result in the smell loss.