Did you or someone you know ever contract COVID-19 and lose your sense of taste or smell? This is called Parosmia. There are people on social media who have tried to theorize ways to regain the ability to smell normally. For example, burning an orange peel. However, if your nasal cavity is damaged, regardless of the strong orange aroma, it may be believed that you will not be able to regain your sense of smell.
So, how was your nose damaged in the first place? The olfactory system contains a zone that detects scents towards the top of the nasal cavity. When molecules diffuse up into the nose, they dock in receptor proteins which ultimately initiates a cascade to create a cellular response. Hence, we are able to smell aromatic molecules.
When someone is infected with the SARS-CoV2 virus, the olfactory epithelial cells are damaged. Doctors have analyzed singular cells following a biopsy in order to examine the effect of the virus on healthy cells. They were able to conclude that the body ignited a innate immunity response, in which swelling occurred where the nerve endings are located. While in some cases the swelling decreased following the innate response, other times, the swelling remained and damaged the tissue.
This can be explained by what we have learned in AP Biology. During an innate immune response, cells release histamines. These dilate blood vessels, while macrophages secrete cytokines. Cytokines attract phagocytes that allow the infected cells and pathogens to be destroyed. The proteins that attempt to interfere with the viruses cause more histamine to be released and overall more swelling. Therefore, the nasal cavity can remain damaged.
However, new research has found that an injection just might help patients with long COVID symptoms to regain their sense of smell. According to Dr. Adam Zoga, one way that patients have begun to smell again is by injecting stellate ganglion blocks into the neck on either side of the voice box. This reaches the stellate ganglia which contains nerve bundles that control your body’s fight-or-flight responses, known as the sympathetic nervous system. Patients also received a steroid injection to decrease swelling.
The patients that participated in the study did not all benefit from it. However, 22 of the 37 that followed up with administrators following the trial injection noticed improvements in one week. Dr. Leigh Sowerby analyzed this data and theorizes that this may work to treat Parosmia because the sense of smell is affected when the sympathetic nervous system is overactive. He believes that this injection “resets” the nervous system, allowing the nerve bundles to return to normal and patients to regain their sense of smell. However, because only 37 of the original 54 patients followed up after the injections, and there was no control group, researchers cannot further extended this claim.
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