Cough and fever—followed by potentially life threatening pneumonia—have been the most talked about symptoms of COVID-19. However, as we learn more about the illness, it appears that the initial symptoms can often be associated with the upper respiratory tract or the nose, mouth, throat. In particular, otolaryngologists in South Korea, China, and Italy have noted that a decrease in the sense of smell and taste—medically known as anosmia and dysgeusia respectively—often precedes the other symptoms of COVID-19. Patrick Colley, MD, rhinologist and skull base surgeon within the Division of Rhinology and Skull Base Surgery at New York Eye and Ear Infirmary of Mount Sinai, answers frequently asked questions about this discovery.
Are these symptoms common among COVID-19 patients?
Observations from physicians in Germany noted that two out of three patients in that country who were COVID-19 positive experienced a loss of smell and taste. In other countries where a larger number of patients were tested for COVID-19, they noted that 30 percent of patients that tested positive for the virus had loss of smell and taste as the major presenting symptom. This means that somewhere between 30 to 60 percent of patients infected with the illness will experience these symptoms. For this reason, The American Academy of Otolaryngology has recommended—in the absence of other respiratory diseases such as allergic rhinitis, acute sinusitis or chronic rhinosinusitis—that a loss of smell and taste should alert physicians to the possibility of COVID-19 infection and warrant serious consideration for self-isolation and testing.
Is this an early or late symptom of COVID-19 infection?
Based on the data that is currently available from other countries with COVID-19 outbreaks, it appears that the loss of smell and taste associated with this virus is an early sign of infection. This means that many individuals will experience these symptoms prior to showing the signs of fever, cough, or shortness of breath more commonly associated with COVID-19.
How can I tell the difference between a loss of smell due to seasonal allergies and a loss of smell due to COVID-19? What should I do if I have these symptoms?
Patients suffering from allergies can experience decreased senses of smell and taste, but will usually have nasal congestion, a runny nose with predominantly clear liquid, and sneezing. They also frequently note itchy eyes, nose or throat. This is very different from the cough, fever, and shortness of breath that is typically seen in COVID-19 patients.
If you experience sudden loss of smell and taste in the absence of recent head trauma, allergic rhinitis, or sinusitis; observe strict self-isolation protocols and contact your primary care doctor, otolaryngologist, or a COVID-19 hotline to discuss the appropriate next steps of care.
How long will the loss of smell and taste last? Will patients fully regain their senses after recovering from COVID-19?
When associated with a viral upper respiratory tract infection, the senses of smell and taste can be expected to return to normal in three weeks to three months. The time course is dependent on whether the virus damaged any nerves in the nasal cavity.
It is unknown at this time how many patients will recover their sense of smell and taste completely after COVID-19. In other upper respiratory tract infections, the recovery rate is 90 to 95 percent by three months after the infection has resolved. Older patients and patients with underlying medical problems tend to have a lower recovery rate. We are assuming a similar recovery rate for COVID-19, but it is too early to provide any accurate data at this time.
How is the loss of smell and taste associated with COVID-19 treated? How can I be evaluated for a decreased sense of smell or taste?
The primary treatment of loss of smell and taste associated with COVID-19 is to treat the viral infection itself. Proper rest, self-care, and monitoring of symptoms are important for ensuring the best outcomes in patients infected with this virus. The loss of senses is only a symptom of this infection and will often resolve after the infection has resolved.
Individuals experiencing a decreased sense of smell or taste in addition to a cough, fever, or shortness of breath should contact their primary care doctor or a COVID-19 hotline (NY/NJ/CT). If this is the only symptom you are experiencing, schedule an appointment with an ear, nose, and throat specialist. Physicians at Mount Sinai’s Department of Otolaryngology are available for telemedicine consults.
Patrick M. Colley, MD
Assistant Professor, Department of Otolaryngology and Division of Rhinology and Skull Base Surgery, New York Eye and Infirmary of Mount Sinai
What Causes the Loss of Smell and Taste?
The sense of smell stems from small olfactory nerve fibers that are found in the superior portion of the nose. These nerve fibers connect through small holes in the skull directly to the first cranial nerve inside the brain. Air that flows through the nose deposits smell particles in the superior portion of the nose where these nerves can detect smell.
This is the same mechanism that is used to taste the majority of the foods that you eat. The taste receptors, or taste buds, that are found in the mouth only detect salty, sweet, bitter, sour, and umami flavors. The remaining flavors are detected by air flow from your mouth back into your nose where they come in contact with the same olfactory nerve fibers. These nerve fibers in the nose are actually where you taste garlic, onions, herbs, and many other flavors commonly used while cooking.
The decreased sense of smell and taste that is often seen in upper respiratory tract infections such as COVID-19 can either be due to nasal congestion causing decreased air flow through the nose and obstruction of the nerve fibers. It may also be caused by a viral infection of the nerve fibers themselves, causing them to stop functioning or die.