COVID-19 is over, but why can't I still smell? | Long COVID: Olfactory Disorder

The Nature of Olfactory Dysfunction and a Traditional Korean Medicine Approach to Recovery

1. Living Without a Sense of Smell: A Common Yet Easily Overlooked Symptom

COVID-19 is over, but many of you still can't smell, right? Especially among middle-aged women, many report symptoms such as "the smell of grilling meat feels like a fishy odor," "perfume makes me dizzy and nauseous," or "all food tastes the same no matter what I eat." Our sense of smell is actually a much more important sense in our lives than we might think. It's connected to everything from the taste of food, emotions, and memories, to safety warnings. However, when your sense of smell doesn't return, it's common to only hear "let's wait a bit longer" at the hospital, and then nothing more. So, why does this olfactory dysfunction occur, and what methods can help with recovery?

2. Olfaction is Not Merely a Nasal Issue

Our sense of smell isn't just about "detecting odors." It's an intricate neural circuit connecting olfactory cells in the nose → olfactory nerve → to the cerebral frontal lobe and limbic system. Odor molecules reach the olfactory epithelium at the top of the nasal cavity, where signals are transmitted to the brain and interpreted as, for example, "This is the scent of a rose." However, COVID-19 doesn't destroy the olfactory cells themselves in this pathway, but rather the surrounding supporting cells. Consequently, the olfactory nerves lose their function, unable to send sensory signals or sending incorrect ones. This leads to either the inability to smell (anosmia/hyposmia) or "parosmia," where existing smells are strangely perceived as different odors.

3. Why Do Some People Recover Quickly While Others Experience Lingering Symptoms?

Despite experiencing the same COVID-19 infection, some people regain their sense of smell within days, while others do not recover even after several months or a year. This difference stems from several factors. Individuals with high genetic expression of ACE2 receptors may experience more severe infections, and recovery speed varies depending on the speed and intensity of their immune response, nerve regeneration capacity, and the stability of their autonomic nervous system. Olfactory dysfunction particularly tends to persist longer in women aged 30-50. This is presumed to be because their innate immunity is strong, but the reorganization of their sensory circuits is slower, or their nervous system structure is sensitive to stress and sleep patterns.

4. Why Does Olfactory Dysfunction Feel Like a Taste Disorder?

This is a common misconception for many people. Although they say "I can't taste anything," in many cases, their sense of taste itself is perfectly fine. More than 80% of what we call 'flavor' is actually olfaction. While basic tastes like sweet, salty, and bitter are perceived by the tongue, complex flavors such as "meat flavor," "coffee aroma," "burnt smell," and "basil scent" are all managed by the nose. Therefore, when the sense of smell is lost, food feels bland and unappetizing, and during the recovery process, it can even be distorted into foul or unpleasant odors. This is what we call "dysgeusia" (taste distortion) or "parosmia" (smell distortion). It's not so much a problem with the sense itself, but rather the brain misinterpreting the signals.

5. Olfactory Training: It's More Than Just Smelling Scents

Here, an important treatment method emerges: olfactory training. This isn't just about "trying to smell things"; it's a rehabilitation exercise that teaches the brain to recognize sensations again. It involves smelling four specific scents – rose, lemon, eucalyptus, and clove – twice a day, intentionally recognizing and visualizing them by saying, "This is rose," "This is eucalyptus," etc. This induces neural regeneration and reconnects the brain's sensory interpretation circuits. This method was actually used even before COVID-19 to treat post-traumatic olfactory loss and post-viral infection sequelae. Surprisingly, it's not something you necessarily do at a hospital; it's a self-care method that can be consistently practiced at home.

6. Traditional Korean Medicine Has Long Called This 'Gae-gyu (開竅)'

Interestingly, in Traditional Korean Medicine, olfactory dysfunction has long been described as "the qi gates being closed" or "the orifices being blocked." To resolve such conditions, 'Gae-gyu-yak (開竅藥)' (orifice-opening drugs) have been used, with strongly aromatic herbal medicines like those containing peppermint, Schizonepeta, and borneol traditionally employed. These herbs were not merely used to clear nasal passages but were understood to "awaken the brain" and reopen sensory circuits. This is precisely what Traditional Korean Medicine refers to as 'Seong-noe (醒腦),' or 'awakening the brain.' From a modern perspective, this translates to neural stimulation through volatile aromatics + activation of cognitive circuits. In other words, it's a concept that directly overlaps with the structure of olfactory training.

7. How Can Acupuncture Treatment Help?

Acupuncture can also be used as an approach. In this case, it's not merely about needling around the nose, but also targeting the olfactory nerve → cerebral sensory centers → and stabilizing the autonomic nervous system. Acupoints like Shangxing (GV23), Yintang (EX-HN3), and Yingxiang (LI20) directly stimulate the olfactory nerve pathway; Baihui (GV20) and Hegu (LI4) promote sensory circuit plasticity; and Shenmen (HT7), Sanyinjiao (SP6), and Neiguan (PC6) stabilize the autonomic nervous system and calm emotional responses. This combination helps to "reawaken" the sense of smell and enables the brain to "interpret" it again.

8. Recovery May Be Slow, But It Is Definitely Possible

The sense of smell is not a simple sensation. It is also an emotional circuit responsible for the richness of our lives, a critical indicator of nerve recovery after infection, and a barometer for autonomic nervous system stability. Rather than simply waiting, it is important to consistently implement a recovery strategy that includes training to recognize scents, restoring vital energy (qi) through herbal medicine, stimulating sensory-cognitive circuits with acupuncture, and ensuring adequate sleep and emotional stability. Smell is a sense that needs to be relearned. Therefore, now might be the best time to start your recovery.

#LongCOVID #COVID19OlfactoryDysfunction