Have you ever gone through the unpleasant symptoms of losing sense of smell (anosmia) and taste (ageusia) during a cold or flu? Did you know that these symptoms can differentiate Covid-19 from the common cold and flu?
In common cold and flu, our immune systems fight these infections via mucus production and inflammation. This combination does an exceptional job of blocking our sinuses. When the specialized nerve endings in the nasal passages are unable to send the full range of information to the brain, one would lose the sense of smell and taste during the phase of an illness. Thus, one will be left with bold flavours. That is the reason why when we're down with the cold or flu, hot tea with honey tastes sweeter and chicken porridge will taste richer.
According to a recent study published in the journal Rhinology on 19th August 2020, the main differences found are Covid-19 patients can breathe freely, don't tend to have runny or blocked nose, and could not detect bitter or sweet tastes. Anosmia is sudden and more profound in Covid-19 patients.
Although the exact mechanism of how the virus affects the sense of smell and taste is still unclear, one study suggests that the SARS-CoV-2, the virus that causes Covid-19, changes the sense of smell or taste in patients by attacking the support cells of the olfactory sensory neurons. These specialized nerve cells detect the chemical compounds that produce a scent called odorants to transmit the information to the brain. The brain then decodes the electrical impulses, which make us able to experience scent. Damage to the support cells prevents the olfactory sensory neurons from responding to molecules that make up different types of scents, thus result in symptomatic changes.
Loss of smell can also be caused by other factors such as neurological conditions, nasal polyps, sinusitis or allergies. Thus, these factors should be ruled out before declaring anosmia as a symptom of Covid-19.
Nevertheless, if you believe you may have Covid-19, stay at home and isolate yourself from other household. Call the nearest centre or hospital to arrange for a swab test.
Image credit:
- https://www.advancedsciencenews.com/wp-content/uploads/2020/05/mask-5008660_1280.jpg
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- https://www.andamanmed.com/wp-content/uploads/2020/03/covid-19.jpg
References:
- COVID-19 affects sense of smell differently than colds, flu | UCLA Health
- Can a Loss of Taste and Smell Be a Symptom of COVID-19? | Healthline
- Loss of smell and taste: Distinguishing between COVID-19 and the common cold/flu | Perio-Implant Advisory
- Brann DH, Tsukahara T, Weinreb C, et al. Non-neuronal expression of SARS-CoV-2 entry genes in the olfactory system suggests mechanisms underlying COVID-19–associated anosmia. Sci Adv. 2020;6(31)
