A day you wake up and feel a stench of feces and urine hovering around the house. It is actually the breakfast coffee. Eat a licorice candy and it tastes like mint, you prepare a fennel salad but in your mouth the taste is that of anise, you make the sauce with the onion but it smells of garlic. For some nose the normal scents of cooking, flowers, aromas, spices can even “smell” of vomit, tar, burnt, rotten or sulfur. In short, life risks becoming hell for patients affected by the “long Covid”, that is, who have come out of the infection but still burdened by the consequences, such as the partial or total loss of smell and consequently of taste.
Feel the smells
And then you have to relearn and smell, following a specific rehabilitation, “Training” and keeping a diary.
«The good news is that it is cured – reveals Professor Gesualdo Zucco, Professor of General Psychology at the University of Padua and one of the leading experts in “testing” for the stimulation of smell – the majority of patients solve the problem in two to three weeks, others in six months at the most. It is more difficult for people to recover from the disorder it lasts a year or more, but don’t despair because the olfactory sensory neurons, unlike the cerebral ones, every month they die and regenerate, so much so that the elderly lose less sense of smell than sight and hearing ». Covid-19 attacks the cells of the epithelium of the nose and infects them, but it is not the receptive cells that send information to the brain, but the support ones, responsible for nourishing them. “When the virus hits them, the information passes damaged to the olfactory bulbs at the base of the skull, because the supporting cells no longer send nourishment – explains Zucco -. Covid-19 binds to Ace2 receptors present in the support cells, lungs, kidneys and testicles, which is why men are more exposed. To recover the sense of smell, the continuous stimulation of the receptors is necessary, which favors the regeneration process ».
The olfactory substances
Attempts at recovery take place through training used successfully even in Parkinson’s patients and in those affected by head trauma. To the patient, blindfolded and seated, are made to feel, twice a day and for one or two months, four selected olfactory substances, namely rose, eucalyptus, lemon and cloves. Each for ten seconds. After the indicated time the sense of smell should return to normal. However, it is also possible to use the standard examination of olfactory functionality with the “Sniffin’s sticks” tests. «We start with the detection of olfactory sensitivity, or detention test, which serves to understand if a person is normosmic, hyposmic or anosmic, that is, if he smells, smells them little or does not feel them at all – explains Professor Zucco -. Pink or n-butyl alcohol are used, present in different concentrations in 16 tubes submitted to the patient in descending order and together with other empty ones, to stimulate him to detect the smell. We proceed to establish the olfactory threshold. If the person is hyposmic, one passes to the tests of discrimination, memory, created by me, and identification, useful to respectively highlight the ability to grasp the differences, for example between coffee and cinnamon or between banana and cherry, to remember the smell first and to give them a name “.
Taste and smell
Between 16% and 33% of patients correctly name the smell, 50% recognizes coffee, rose, vanilla, garlic, basil and parsley. Sandalwood, leather, bergamot and tar are instead among the most difficult to identify, pineapple and fish get them wrong almost all, as is fennel confused with anise, while cloves are often perceived as cinnamon. What not many know is that the taste, classified into salty, bitter, sweet and sour, it is closely related to the sense of smell. «If you plug a person’s nose and put droplets of garlic on his tongue, he only feels bitterness – confirms Zucco – when you free his smell, he recognizes the taste. If you use cinnamon powder, it feels like you have a handful of sand in your mouth. In short, when you start to smell the smell again, the taste also returns“. In the case of parosmia, good smells become repulsive. “But other anomalies may emerge. For example, a girl suffering from head trauma did not even smell rotten eggs, but she could smell bergamot – smiles the teacher -. At the end of the therapy he gave me a bottle ».