Loss of taste and smell is probably one of the most peculiar commonly-reported symptoms of a COVID-19 infection.
COVID-related parosmia and dysgeusia describe a change in taste or smell. Anosmia and ageusia, on the other hand, describe a loss of smell and taste entirely. Either might plague you after getting the coronavirus. What’s the connection?
Is COVID-related loss of smell and taste physical or neurological?
Loss of taste and smell isn’t anything unheard of—in fact, many upper respiratory viral infections (URIs) may temporarily leave you taste-blind or smell-blind.
On average, this change will only be long-term for around five percent of people. COVID-19 patients, however, experience this problem at a much higher rate, the majority of them reporting no rhinorrhea or nasal congestion alongside.
Instead, it’s speculated that the coronavirus disrupts one’s olfactory sensory neurons (OSNs), located in the olfactory epithelium, not in the brain. The virus reduces smell and taste acuity, blunting their ability to detect and differentiate ordinarily-familiar smells and tastes.
Because this COVID symptom is such an oddity, it can be used to rule out the possibility of another type of illness before testing. Yes, you read that right.
Smell, taste, and COVID prognosis
This retrospective report shows that loss of taste or smell might actually be able to indicate how severe a patient’s COVID case might end up becoming—the correlation is so strong that the authors suggest using it as a means of triaging incoming COVID patients en masse.
Why is this the case? The release of signal-disrupting double-stranded RNA, dsRNS, into the extracellular milieu may have something to do with it, although nothing has been determined definitively.
This phenom is triggered by the virus and is not as likely in the case of a significantly compromised individual. These signals may infiltrate and degrade the system’s ability to function by way of toll-like receptor signaling pathways, or TLR3.
Others believe that the link is actually genetic. The genes in question help orchestrate the metabolism of taste and smell sensations; as the virus accumulates in these olfactory support cells, the sustentacular cells in particular, it impairs them and one’s ability to use them.
These genes, UGT2A1 and UGT2A2, are put to blame primarily due to their localization, but not much else is known aside from the fact that they do play a role in receiving olfactory signals and interpreting them. The mystery lives on.
All of these minute events and factors may result in a diminished perception of smell and taste intensity in the healthiest COVID victims. Again, the jury is still out, but there is plenty of compelling evidence supporting these claims.
Should you get tested?
If your favorite tastes and scents start to turn for seemingly no reason, you might already have COVID-19. Some report things like juice and coffee beginning to taste like gasoline—if the colloquial claims are anything to go by, the change will likely be more than obvious.
Take some time today to stop by and sniff the roses with us. At the very least, we’ll be able to help you get to the bottom of the matter.