A total of 73 patients diagnosed with SARS-Cov–2 by PCR or serology were contacted by this service throughout the months of March and April. Of these, a total of 51 patients wanted to participate in the study and met the inclusion criteria. Of the 51 patients who met the inclusion criteria, 10 patients could not be explored before analyzing the data collected here, since they were still symptomatic or in preventive isolation, so that the total number of patients who went to the face-to-face consultation was 41 patients. The mean age of the patients was 43.82 +/- 10.76 years (range 18–67). There were 44 women and 7 men. The most prevalent patient comorbidities were hypertension (9.8%), diabetes (3.9%), and autoimmune diseases (11.8%). 15.7% of the patients had been adeno-tonsillectomized in childhood. Only 3.9% required hospitalization at the acute moment of infection.
Subjective olfactory results:
Of the total number of patients in the sample, 52.9% reported nasal obstruction, 23.5% reported anterior rhinorrhea, and 19.6% reported posterior rhinorrhea. Only 17.6% reported ear pain and 41.2% reported sore throat. Only 2 of the 51 patients (3.9%) required hospitalization at the acute moment of infection. (Figure 1).
Of the total number of included patients, 86.3% reported subjective anosmia at the acute moment of infection. 94.1% reported having had other systemic symptoms such as tiredness, headache, diarrhea, myalgia, cough, and fever. Regarding the temporal relationship between olfactory dysfunction and the rest of the systemic symptoms, 11.8% reported experiencing it before the rest of the symptoms, 23.5% at the same time, and 49% after the rest of the symptoms. (Figure 2).
Subjective olfactory dysfunction at the acute moment of infection was rated on a subjective scale ranging from 0 to 4 (with 0 = I smell everything well; 1 = I have noticed some loss of smell; 2 = I smell less than usual; 3 = I smell practically nothing; 4 = I don’t smell anything). The results were 13.7% of patients reported no loss of smell, 9.8% noted some loss of smell, 9.8% smelled less than usual, 27.4% smelled practically nothing, and 39.2% did not smell anything. (Figure 3).
The duration of subjective olfactory dysfunction was classified as follows: non-dysfunction, duration from 1 to 4 days, from 5 to 8 days, from 9 to 14 days, and more than 15 days. The distribution of the sample was as follows: 19.5% of patients reported not having experienced olfactory dysfunction, 7.3% had dysfunction for 1 to 4 days, 7.3% for 5 to 8 days, 46.3% for 9 to 14 days, and 19.5% for more than 15 days. (Figure 4).
Objective olfactory results
Olfactometry was performed using the ‘Sniffin Stiks’ test, which was administered to the 41 patients who were able to attend the face-to-face consultation. The following results were obtained.
After a month had passed from the acute moment of the infection to the face-to-face consultation, 9 patients, or 22% of the sample, still presented with olfactory dysfunction that was observed in olfactometry. Of these 9 patients, 5 obtained a score of 7 to 9 in the test, so they were diagnosed with hyposmia, and 4 obtained a score from 0 to 6, so they were diagnosed with anosmia.
Regarding the characteristics of the patients to whom the olfactory dysfunction could be determined, there were 7 women and 2 men. Only 22.22% were smokers, 11.11% were hypertensive, and 33.33% had been adeno-tonsillectomized. There was no diabetics or dyslipidemics among them, and none suffered from autoimmune diseases, or from previous pathologies in the ENT area. None of the patients had required hospitalization.
Regarding symptoms in the ENT area, 77.77% reported not having suffered from either anterior or posterior rhinorrhea, 66.6% reported having had nasal obstruction, 66.6% reported not having sore throat, and 88.88% reported not having had ear pain. (Figure 1).
Regarding objective dysfunction and the relationship of this symptom with the rest of the systemic symptoms, 11.11% had suffered from olfactory dysfunction as the only symptom of SARS-Cov–2 infection, 11.11% had suffered loss of olfaction before the rest of the symptoms, 33.33% suffered the loss of olfaction at the same time as the rest of the symptoms, and 44.44% suffered the loss of olfaction after the rest of the symptoms. (Figure 2).
Regarding subjective olfactory loss grading on a scale of 0 to 4, the patients who were finally diagnosed with olfactory dysfunction defined their loss as follows: 11.11% rated their loss as “I have noticed some loss of smell,” 22.22% as “I don’t smell practically nothing,” and 66.66% as “I don’t smell anything.” (Figure 3).
Regarding objective olfactory dysfunction and subjective duration of dysfunction, 11% reported having experienced a duration of 5 to 8 days, 11% reported having had a duration of 9 to 14 days, and 77% reported having had a duration more than 15 days. (Figure 4).
Subjective vs. objective olfactory association
Statistical significance could be demonstrated between the group of patients with anosmia/hyposmia and the Sniffin Sticks test (p-value: 0.013). However, statistical significance could not be demonstrated between the group of patients with subjective anosmia and the actual anosmia evaluated using the Sniffin Sticks test (p-value: 0.235).