A COVID-19 viral infection can result in one of the most unpleasant COVID symptoms there is: losing your sense of smell and taste. Experiencing loss of taste and smell can be a unpleasant ordeal for many COVID patients.
If you have suffered from a loss of smell and taste after COVID-19, there’s good news and bad news. The good news is, you can regain your lost senses. The bad news is, you may need to put a lot of time and effort into training your brain before you can regain normal sensory function.
Thankfully, most COVID-19 patients who reported losing their senses of taste or smell have been able to regain them
over time.
If you have experienced taste or smell loss, this guide can help you figure out how to restore your senses to their pre-COVID levels.
How does COVID-19 affect your ability to smell and taste?
COVID-19 can negatively affect your ability to smell and taste in a number of ways. You can experience a reduced sense of smell (hyposmia), an abnormal or altered sense of smell (parosmia), or even a complete loss of smell (anosmia).
Like other viral illnesses like the common cold or flu, COVID-19 can cause malfunctions in your olfactory system, affecting how you sense smells and tastes. While this can happen with any viral infection, loss of smell is very common amongst COVID-19 patients. Studies suggest that up to 60% of COVID-19 sufferers experience some kind of olfactory dysfunction.
Taste and smell are closely linked senses. When you experience loss of smell , it’s highly likely that loss of taste comes with it. Your taste buds depend on your olfactory receptor neurons to tell your brain how something tastes. If your olfactory cells are not functioning properly, your gustatory taste buds will not be able to function well, either. This is the reason why you can’t taste anything when you have nasal congestion due to a viral illness like the common cold.
Why does COVID-19 make you lose your sense of smell and taste?
Scientists have not yet figured out the exact reason why COVID-19 makes you lose your sense of smell and taste. One theory is that, like other viral infections, COVID-19 causes olfactory dysfunction because of the inflammation in your nose and sinuses. This prevents smells from getting to your olfactory bulb. However, nasal obstruction only accounts for short-term smell loss, much like local inflammation caused by the common cold or other viral infections.
Longer -term loss of smell can be caused by a variety of other effects of COVID-19 that affect a person’s olfactory epithelium. The olfactory epithelium is a group of cells that process smells and send olfactory signals to your brain. It is suspected that COVID-19 damages the supporting cells (sustentacular cells and microvillar cells) in your olfactory epithelium, which are responsible for metabolically and physically supporting the other olfactory epithelial cells – most importantly, the olfactory receptor neurons.
Your sustentacular cells have ACE-2 (Angiotensin converting enzyme-2) receptors that are the primary point of entry for COVID-19. When COVID-19 reaches your nasal mucosa, it hooks into your support cells’ ACE-2 receptors, affecting your olfactory neurons and leading to smell loss. Studies that took nasal samples, brain samples from hamsters, and MRI scans have confirmed that COVID-19-related neuronal damage is associated with anosmia in COVID-19 patients.
COVID-19 has been shown to cause neuronal damage due to its ability to cross the blood-brain barrier by anterograde axonal transport via the olfactory sensory neurons, which can also damage the central nervous system. While it’s alarming that the coronavirus disease can invade your brain through the olfactory sensory neurons and support cells in your olfactory epithelium, it is still possible to regain your sense of smell through olfactory training.
Can Loss of Taste and Smell Be Restored After COVID-19?
Loss of taste and smell can be restored after COVID-19, though it may take for some patients longer than others. In most COVID-19 patients, the sense of smell returns within two months, but for a minority of COVID-19 sufferers, anosmia can last as long as a year. Very few patients report a permanent loss of smell sensation and olfactory function.
Many COVID-19 sufferers undergo smell training as a part of patient care to restore their sense of taste and smell. The earlier you start treating smell loss, the quicker you will be able to restore regular olfactory function.
How long does loss of taste and smell last with COVID?
The loss of taste and smell associated with COVID-19 can last from a couple of months to over a year, depending on the ways that the coronavirus disease affects the individual. You can also speed the process up by undergoing olfactory training.
If you want to find out whether or not your sense of smell has returned after COVID-19, you can perform a smell test by attempting to smell two objects with powerful but contrasting smells, such as coffee beans and an orange. You can also check for taste loss with the same process, tasting two foods with strong flavours to see if your taste buds can detect a difference.
When do smell and taste return after COVID-19?
Smell and taste can return as soon as within 60 days after COVID-19, with about 75% of people regaining it in that time frame. Eighty-six percent of COVID-19 patients who suffered from losing their sense of smell report regaining it within four months, while 96% report regaining their sense of smell within one year.
While it’s rare to permanently lose your sense of smell and taste due to COVID-19, it is still possible. A very small percentage of people report still suffering from persistent anosmia even a year after the initial COVID-19 infection.
How do I regain my taste and smell after COVID?
You can regain your taste and smell after COVID-19 by actively undergoing smell training.
Smell recovery can be accelerated with frequent olfactory training, as well as other potential treatments that can improve olfactory dysfunction and treat anosmia. But while there are many ways to treat loss of smell and taste after COVID-19, some are more effective than others. Ask your doctor to administer a verified smell test before undergoing any of these potential treatments.
Smell training
Olfactory training has proven to be an effective way to treat anosmia and olfactory dysfunction in COVID-19 patients. If you have noticed a loss of smell or distorted smell sensation after COVID-19 or other viral infections, undergoing smell training can help you retrain your brain to recognize the signals from your olfactory sensory neurons.
Retraining your sense of smell is fairly simple, but it must be done consistently over weeks or months to improve odour detection. To do smell training at home, you need to choose four different smells with distinct scent profiles.
You can choose objects with any smell, but you should ideally stick to the four main categories of smell: spicy, fruity, floral, and resinous. You can use real fruits, flowers, spices, or other household objects to train your smell, as well as various essential oils.
Smell each scent for 15 to 30 seconds, rest your nose for five seconds, then switch to another scent. While sniffing your chosen scent, focus on identifying the differences between each smell while recalling your memories and experiences associated with that particular smell. This helps reinforce the connection between your olfactory nerves and your brain’s olfactory cortex.
Perform smell training once twice a day for at least a month. Much like other forms of physical therapy, olfactory training takes some time before you notice results. This process usually takes at least three months but can take longer depending on the severity of your smell loss.
Fluticasone nasal spray
A study conducted in 2021 tested the efficacy of using fluticasone nasal spray as a treatment for olfactory dysfunction, as well as triamcinolone paste for taste dysfunction.
The nasal spray and oral paste were administered to 60 participants for five days. It was found that there was a significant improvement in their ability to distinguish between smells and tastes compared to the control group.
Fluticasone nasal spray is a prescribed medication, so you will need to ask your doctor if it is right for you before you can use it.
Oral corticosteroids
The use of systemic corticosteroids to treat COVID-19-related anosmia has been widely studied, though this treatment can delay your body’s recovery from the virus.
A study conducted in 2020 tested the efficacy of oral corticosteroids in restoring patients’ sense of smell. One group was given oral corticosteroids while undergoing olfactory training, while the other group only did olfactory training. Researchers found that the corticosteroids group significantly improved their olfactory score compared to the group that only underwent olfactory training.
Insulin
In 2021, a study was conducted on COVID-19 patients to test the viability of intranasal insulin films in treating anosmia. The formulated insulin films were administered to 20 patients, and it was found that they performed better on odour discrimination tests than the control group.
This treatment is not widely available yet, though it won’t hurt to ask your doctor about it if your sense of smell hasn’t returned after a year.
Coffee
Believe it or not, coffee can help restore your sense of smell after COVID-19. In a study conducted in 2020, researchers observed that the caffeine in coffee helped speed up the smell recovery of COVID-19 patients. The study was performed using 14 grams of coffee in one cup, totaling 15-20 mg of caffeine.
In patients with no underlying conditions, coffee helped improve the sense of smell and taste after five to seven hours, while patients with underlying conditions like diabetes and hypertension reported an improvement within two to four days.
Conclusion
Most COVID-19 patients who experience a loss of taste and smell usually regain those senses naturally over time. Seventy-five percent of COVID-19-related anosmia sufferers regain their sense of smell and taste within 60 days, and 96% of them regain it within one year of infection.
However, if you are still having difficulty smelling after a COVID-19 infection, there are ways that you can speed up the recovery of your olfactory and gustatory senses. Olfactory training can help your brain repair the connections between your olfactory cortex and sensory neurons, though it can take anywhere from two to six months to retrain your olfactory nerves.
You can also ask your doctor about the alternative treatment options for COVID-related anosmia. Intranasal insulin films, oral corticosteroids, and fluticasone nasal spray all have been shown to be somewhat effective in recovering your sense of smell and taste.
