By: Dr. Madeleine Samuelson Herman, MD, MPH
Whether it’s from a cold, COVID, or chronic sinus disease, smell loss is a stinks. I frequently talk to patients about the causes and treatment for anosmia, or the loss of sense of smell.
Why is your sniffer suffering? Well there are a couple of potential problems.
#1 COVID: COVID causes smell loss in roughly 80% of those with the disease, with 7% still suffering from smell loss 1 year later. Studies show that the virus attacks the cells that provide nutrients to the odor-sensing nerves.
#2 Post-viral: SARS-CoV-2 isn’t the only virus that can cause smell loss. The same viruses that can cause a cold or upper respiratory infection, can also cause anosmia.
#3 Trauma: Head trauma can also cause altered sense of smell by shearing the tiny nerve fibers as they enter the brain.
#4 Obstruction: Whether it’s from a septal deviation or sinus disease, a stuffy nose can certainly affect one’s sense of smell. If smells can’t enter the top of your nose, you don’t register them.
#5 Medications, Chemicals: There are multiple medications and chemicals that can alter your sense of smell. They include tobacco smoke, industrial solvents and many frequently used medications.
#6 Vitamin Deficiency: Zinc deficiency has been linked to smell loss.
#7 Neurologic Problems: Parkinson’s disease, Alzheimer’s and Schizophrenia are but a few of the many neurologic problems also associated with smell loss.
If you are suffering from smell loss or altered sense of smell, discuss this with your physician. They may examine you to determine the cause of your smell disturbance. Because anosmia can result from many different conditions, your doctor will address any potential causes. For example, if you have allergic sinus disease, treating that may help restore olfactory sense. If they discover a nasal tumors, nasal polyps or nasal deformities, you may require surgery. In other cases, anosmia can be an early symptom of another disease, such as Alzheimer’s or Parkinson’s.
Smell Retraining Therapy
For patients after COVID, they may benefit from a treatment called smell retraining therapy (SRT). The process of SRT involves the repeated presentation of different smells to the nose, stimulating the olfactory system and establish a memory of that smell.
It is best to start with at least four different scents, especially smells you remember. The most commonly recommended fragrances are rose (floral), lemon (fruity), cloves (spicy), and eucalyptus (resinous). You can either purchase a kit (here’s a link), or you can use your own spice rack.
Take sniffs of each scent for 10 to 20 seconds at least once or twice a day. While sniffing, it is important to be focused on the task. Try to concentrate on your memory of that smell. After each scent, take a few breaths and then move on to the next fragrance. It is recommended that you do this for at least 12 weeks (three months), but you can do it longer, alternating the scents if you like.
SRT is believed to work as a combination of the unique ability for smell nerves to regrow while encouraging improved brain connectivity. Either way, try not to get discouraged; it is common for this process to take some time before you start to smell anything, and that is okay. To learn more, check out the American Academy of Otolaryngology website, here