Smell loss is among the very first signs of COVID-19, and nearly everyone who has COVID-19 has some degree of smell loss. Dr. Richard Doty, Director of the Smell and Taste Center at Penn Medicine Ear, Nose and Throat, outlines all you need to know about the effects of COVID-19 on your ability to smell.

How do viruses affect sense of smell?

The most common cause of smell loss in the general population is viruses, like the novel coronavirus that causes COVID-19. Upper respiratory infections, for example, are a common way in which smell is damaged. This is because the viruses enter those cells associated with smell and damage them.

In some cases, viruses can be neurotropic. This means they enter into nerve cells, and the virus can then spread into the brain through the olfactory receptor cells, causing a number of different diseases.

What research is being done on COVID-19-related smell loss and what do we know so far?

At the University of Pennsylvania, we’ve been doing collaborative research with a number of institutions, including researchers in Tehran, where we’ve done the first study to show that smell loss is in fact present. There have been many self-reports of smell loss occurring, but no one has actually given olfactory tests. In relation to COVID, we know that many people get their sense of smell back.

Studies happening at Penn, along with other institutions, show that within two to four weeks, most people have their sense of smell return, although not quite to the level they had it before. On the other hand, around 25 percent or more of people with smell loss will experience it long-term. We don’t know for sure whether it’s permanent, but it’s quite possible in many cases.

What if I think I’m losing my sense of smell?

If you’re concerned about losing your sense of smell, you can use common household items, like vanilla extract, to test it. If you discover that coffee has no taste or chocolate seems to no longer have any taste other than bitterness or sweetness, then it’s likely that you may be experiencing smell loss.

When you chew food, molecules go up through the rim of the nasal cavity to reach the olfactory receptors at the top of the nose. For that reason, things like coffee and chocolate do not have any “taste”– it’s really a smell. Many people think they are experiencing a loss of taste, but actually, the loss is due to decreased flavor sensation from the sense of smell.

If this loss has happened over a very rapid period of time, there’s a possibility that you have COVID-19. You should contact your primary care doctor, who will conduct further testing.

How is Penn ENT currently operating and what are your plans moving forward?

Penn Medicine is currently seeing patients with a focus on individuals who have the most serious complications. Penn Medicine has been largely practicing telemedicine for the safety of patients, providers and others involved. However, for patients that require in-person care, we are taking full precautions to welcome them into all of our facilities in a safe and proper manner.

Why is our sense of smell so important?

Your sense of smell may be more important than you realize. In addition to determining the flavor of foods and beverages, if you can’t smell, you’re less likely to detect leaking natural gas, spoiled food, and other environmental dangers.

Just like the other senses, it’s important to pay attention to your sense of smell and seek medical help if it declines. During these unprecedented times, if you’re experiencing smell loss or other problems that may require treatment, contact Penn ENT to discuss your symptoms and a possible treatment plan.