Smell is only possible because the olfactory epithelium in the nose does all the work of recognizing odor molecules and taking them to the brain. There are neurons and support cells to help you with this work. Were it not for them, we would not be able to distinguish the smell of bread coming from the oven or the gas leak.
And the smell of these scents is essential to our existence, also for safety reasons. But the coronavirus has a special property: it affects the olfactory epithelium in particular, which suddenly causes a lack of smell and taste. So much so that this symptom is the one that turns on the warning. “Loss of smell is very common. We estimate that two-thirds of patients have this symptom, which is one of the most common symptoms in Covid, and helps make the diagnosis, ”says Fabrizio Romano, ENT specialist at Moriah Hospital.
What about the flu so that we also stop smelling and tasting? The example is different. “With the flu, the smell is reduced because the nose is clogged and the smell molecules do not reach the olfactory epithelium. This is not the case with Covid. The patient breathes normally, his nose is not blocked and he loses the smell, ”he says.
To understand the tendency caused by the coronavirus in smell and taste, it is important to understand how we smell. The neuron in the nose is exposed: it receives odor molecules and converts them into an electrical signal that goes to the brain, which it interprets as odor. Support cells help you with this work. “The coronavirus attacks the carrier cells and causes inflammation, which eventually interrupts the transmission to the brain and suddenly loses the sense of smell,” he explains.
Loss of taste occurs due to traction because it is the smell that gives the food its special flavor. The tongue recognizes sweet, salty, sour, bitter and umami (typical of Oriental foods), but is not affected by the coronavirus. Thus, patients continue to experience these tastes, but not the taste of the food. “A person starts eating more salty or sweet things because they are aware of it,” he says.
In cases of mild inflammation, the patient will smell again in a few days or weeks. On the other hand, when the inflammation is more intense, the neuron dies and the sensation takes months to return. “People have this longest odor loss. Fortunately, the olfactory neuron is the only one in the body that regenerates, so neurons regenerate, but it takes months, ”he says.
Therefore, it is imperative to pay attention to the loss of odor and seek out an otolaryngologist to begin treatment and recovery of this sensation. “In the initial phase, we used anti-inflammatory drugs. There are drugs that help the neuron to recover, which we use later. ” In the worst cases, there is olfactory therapy, which is almost similar to physiotherapy: the patient inhales familiar odors and, even without feeling them, thinks about the smell he has. For example: when you smell eucalyptus, think of the smell of eucalyptus. “It thus reconnects the neuron that senses this molecule with the part of the brain that interprets it as eucalyptus.” Thus, the inclination can be corrected in terms of smell and taste and smelled and tasted again as before.
How we breathe
It all starts with odor molecules reaching the olfactory epithelium. There, they stimulate neurons and support cells that transmit an electrical signal to the brain that recognizes odor. The coronavirus inflames the support cells and interrupts the whole process.
Noise that doesn’t exist
Although ringing in the ear is less common, it occurs as a symptom of Covid-19, along with loss of smell and taste. “It’s not as common as odor loss and it’s not as well studied because it can be caused by many things, including stress, bruxism, anxiety and excess caffeine, as well as hearing loss. We don’t know exactly if coronavirus causes this tinnitus directly or if it’s not indirect. stress, anxiety, “explains otorhinolaryngologist Fabrizio Romano.