COVID-19 Symptoms: Study Indicates That Nasal Dryness Is Possibly An Early Warning Sign Of SARS-CoV-2 Infection
: Researchers from the University of Barcelona-Spain, Instituto de Salud Carlos III-Spain, University of Múrcia-Spain, University of Hawai-U.S. and University of Oxford-UK have in a new study concluded that nasal dryness could be an early warning sign of COVID-19 disease.
One of the entry routes of SARS-CoV-2 is the nasal epithelium. Although mounting evidence suggests the presence of olfactory dysfunction, and even anosmia, in individuals with COVID-19, it is not clear whether these patients also suffer from other “nasal” symptoms that may influence their olfaction.
A group of 35 patients with COVID-19 (and a control group matched in gender and age) were surveyed about the presence of a variety of nasal symptoms that may be associated to drastic perturbations experienced in the nasal cavity (e.g., “excessive dryness” and/or a continual sensation of having had a “nasal douche”).
The study team used a cross-sectional, retrospective survey, targeted at the general population by means of non-quoted, non-random, snowball sampling.
Symptoms were assessed with absence/presence responses. The possible association between two continuously distributed latent variables from categorical variables was estimated by means of polychoric correlations.
Interestingly more than 68% of the patients reported at least one “nasal” symptom. The clinical group also experienced “a strange sensation in the nose” and having excessive nasal dryness significantly more often than the control group.
Fifty-two percent of the patients (but only 3% of the control group) reported a constant sensation of having had a strong nasal douche. Nasal symptoms predominantly co-occurred with anosmia/hyposmia, and ageusia/hypogeusia, appeared principally before or during the other symptoms of COVID-19, and lasted for twelve days, in average. The presence of these nasal symptoms, and their early occurrence, could potentially facilitate early diagnosis of COVID-19 and initial social distancing efforts.
The study findings were published on a preprint server and are currently being peer reviewed. https://www.medrxiv.org/content/10.1101/2020.11.18.20233874v1
The study findings could potentially help control COVID-19’s spread by facilitating early diagnosis and making it possible to practice effective social isolation measures earlier.
To date the asymptomatic carriage of SARS-CoV-2, the virus that causes COVID-19, has been one of the limiting factors for the efficient containment of viral spread in the current pandemic. Individuals infected with the virus need to be identified and isolated rapidly (and in a cost-efficient manner) to restrict SARS-CoV-2’s transmission. To do this, it is necessary to both identify and understand the clinical manifestations of this disease. This is especially valuable given the current shortfall in testing kits in many parts of the world.
It has been found that alterations in taste or smell are thought to be present in about 80% of COVID-19 cases in Europe.
This development is possibly linked to viral entry into angiotensin-converting enzyme 2 (ACE2)-bearing epithelial cells, including the olfactory epithelium in the upper part of the nasal cavity. The ACE2 receptor is the site at which the spike protein of the virus gains entry into the host cell to commence viral replication. This development could be associated with damage to nasal and brain cells.
Importantly goblet cells, which are found scattered among epithelia in the respiratory and intestinal tract, are viral targets, since they express ACE2. These mucin-producing cells are also in the respiratory epithelium of the nose. The breakdown of the mucin barrier by the action of the virus on the goblet cells could also contribute to the anosmia/hyposmia, since the odorant molecules may probably stick to their receptors with the help of the mucus.
Significantly mucus reduction could also cause strange sensations in the nasal cavity, in which case virus-induced this could also herald COVID-19 earlier than other symptoms. https://link.springer.com/article/10.1007/s00405-010-1391-z
This study sought to determine if these changes were possibly linked to other symptoms that could explain them. The researchers explored nasal symptoms in a group of 35 patients, including only those which could possibly cause marked disruptions in olfactory function. They validated their observations with a control group of similar age and sex composition.
The study team found that almost 70% of the patient group said they had one or more nasal symptoms, including “a strange sensation in the nose,” almost 37 times more often than the control group.
Also over 60% said they felt an abnormal dryness of the nose versus around 15% of controls. Additionally, over half of the patient group said they felt as if a strong nasal wash had been administered, while only one member of the control group reported this sensation, making the patient group risk 32-fold higher for this symptom.
It was also found that in the patient group, the nasal symptoms mostly occurred in the same period as the alteration in smell and taste, or before the latter began. The mean period of such symptoms was 12 days, on average, versus 5 days in controls. Overall, about 85% and 80% of the patients had issues with loss of smell and taste, respectively, which is congruent with other reports on the subject.
The main significance of these study findings is not that they are life-threatening, or contribute to the morbidity, but that they are 1) distinct from anosmia or ageusia, and 2) present early in the course of the illness. This may signal that they should be included in early diagnosis protocols for COVID-19, such as early monitoring and adjusted social isolation measures to prevent transmission.
The study findings may be related mechanistically, as described in the above hypotheses. The entry of the virus into the respiratory nasal epithelium, especially the goblet cells, may cause a sudden disruption of the mucus barrier, which in turn causes the epithelium to dry out. This also reduces olfactory sensitivity by decreasing the number of odorant molecules that can adhere to their receptors, in the absence of the sticky mucus layer. This could account for both the aberrant nasal sensations and the loss of smell.
Also the viral infection could cause direct damage to the respiratory epithelium. This could be a topic for further research, which could pinpoint the exact point in time at which the abnormal nasal sensations, such as excessive nasal dryness, give way to other symptoms of COVID-19 that are more widely recognized.
The study team concludes “The presence of these nasal sensations could be taken into account for both diagnostic and social distancing purposes, especially in those situations in which RT-PCR tests cannot be administered to non-severe cases.”
The team also said, “Considering that nasal dryness could easily be related to some initial damage caused by SARS-CoV-2, future studies might determine the point in time where patients experiencing abnormal nasal dryness begin to develop other COVID-19 symptoms.”
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