COVID-19 Symptoms: How to Distinguish the Loss of Taste and Odor caused by COVID-19 from the Odors Commonly Seen Due to a Bad Cold or Flu?

Loss of taste and smell senses is a common symptom of COVID-19-patients report being unable to distinguish whether they are wearing perfume or finding nuances in balanced dishes. 

Anyone who has a cold or suffers from the flu may think they can be linked because these diseases also tend to make the rich scents and exfoliating flavors that are difficult to obtain and attractive.

A new study has revealed how the odor loss associated with COVID-19 infection is different from the odors you might normally experience due to a bad cold or flu.

A study published on Wednesday found that although COVID-19 patients may lose their sense of odor, they can breathe freely without a runny or blocked nose, and no bitter or sweet taste can be detected.

The research from the European Expert Panel (including Professor Philpott) on anosmia, was conducted at the University of East Anglia.

Researchers including those from the University of East Anglia (UEA) in the United Kingdom said that the study is the first to compare the differences between people with COVID-19 smell and taste disorders and people with other causes of upper respiratory tract diseases. The researchers hope that their work will help develop odor and taste tests for rapid coronavirus infection screening in central care and emergency departments.

The study, published in the journal Rhinology, has compared the differences between COVID-19 odor and taste disorders and other causes of upper respiratory tract infections for the first time.

The finding, proclaimed in the journal Rhinology, confirmed the theory that COVID-19 infects the central nervous system and brain.

A study found that short-term loss of odor may be due to cleft syndrome. In such a case, the swelling prevents the aroma from reaching the olfactory neurons. Another finding is that some coronavirus patients develop brain swelling and delirium, while others developed neurological diseases that can lead to paralysis, such as Guillain-Barré syndrome. Due to COVID-19 consequences, a stroke was also detected. 

Carl Philpott, a lead researcher, and professor at the UEA Norwich School of Medicine said: “The loss of odor and taste is a prominent symptom of COVID-19, but it is also a common symptom of a severe bad cold.

Philpott further said: “We wanted to discover what is the main difference between the odor loss caused by COVID-19 and the odor loss caused by a blocked nose due to a bad cold.”

The research team conducted odor and taste tests on a control group of 10 COVID-19 patients, 10 severe cold patients, and 10 healthy people, all of whom were matched by age and gender.

Philpott stated that we want to see if their odor and taste test scores can help distinguish COVID-19 patients from those with severe colds.

The researchers pointed out that the behavior of COVID-19 illness is quite different from other respiratory viruses, for example, by causing an overreaction of the body’s immune system (called a cytokine storm) and influencing the nervous system.

They found that in the COVID-19 patent, the loss of odor is more serious, their ability to recognize odors is also lower, and they cannot recognize bitterness or sweetness. The researchers said that compared to those patients with cold, COVID-19 patients seem to have this loss of true taste.

Philpott said that this is very exciting because it means that smell and taste tests can be used to distinguish COVID-19 patients from those who often catch flu or cold.

Although such tests may not be a substitute for formal diagnostic tools such as throat swabs, they may be needed if routine tests or rapid screening are not possible – especially in primary care, emergencies, or at airports, he added.

The researchers also asserted that there are altogether several things going on, so when compared with patients with severe colds, the loss of smell and taste in COVID-19 patients is completely different.

More research is needed to understand whether genetic variation in people’s sweet and bitter receptors may make them susceptible to COVID-19, or conversely, whether COVID-19 disease directly or through cytokine storms alter the function of these receptors -overreacting the body’s immune system.

At the same time, another study published in the ERJ (European Respiratory Journal) showed that there is a high level of a protein called angiotensin-converting enzyme II (Ace-2) in the nose area responsible for smell, which may be related to loss of scent in Covid-19 patients. Ace-2 is considered to be the entry point that allows the COVID-19 to enter into the human body cells and cause infection.

A team of scientists including experts from Johns Hopkins University in the United States analyzed the posterior tissue samples of 24 patients with sinus problems but not diagnosed with Covid-19.

They also studied the biopsies of the trachea of 8 patients

The researchers found that the Ace-2 level content in the lining cells of the olfactory epithelium is 210 to 700 times higher. Compared with other tissues in the nose and trachea, the area on the back of the nose is the area where the human body detects odor.

The researchers said that this was regardless or nothing to do with whether the patient has been treated for chronic rhinosinusitis or other diseases.

In a study, Director of the Johns Hopkins Sinus Center, Professor Andrew P. Lane declared: We are now conducting more experiments in the laboratory to see whether the coronavirus actually used these cells to enter and infect the human body or not. If this is the case, we may be able to tackle and resolve the infection through antiviral therapy directly through the nose.