Smell loss affects around 15-20% of the population, with a major effect on the quality of life. The most common complaint is the impairment of the eating experience, with around 90% of patients reporting this issue. A study conducted at a specialized taste and smell clinic investigated if food and cooking can have a positive effect on the enjoyment of food, subjective cooking skills, and quality of life in patients with smell loss. The 49 participants in the study received a 5-week cooking school course that focused on emphasizing the other senses to regain the enjoyment of food. Participants gained more confidence in cooking, and their quality of life improved significantly. Positively evaluated recipes were adjusted based on feedback and published as free e-books in Danish, German, and English. Eating and cooking are multisensory experiences, and the perception of food depends on the complex interaction of senses and surroundings. If the olfactory input is reduced or absent, both the enjoyment and cooking experience can be negatively affected. Therefore, focusing on food and cooking can have a positive impact on patients with smell loss.

Olfactory system is a vital sensory system in mammals, giving them the ability to connect with their environment. Anosmia, or the complete loss of olfaction ability, which could be caused by injuries, is an interesting topic for inspectors with the aim of diagnosing patients. Sniffing test is currently utilized to examine if an individual is suffering from anosmia; however, functional Magnetic Resonance Imaging (fMRI) provides unique information about the structure and function of the different areas of the human brain, and therefore this noninvasive method could be used as a tool to locate the olfactory-related regions of the brain. In this study, by recruiting 31 healthy and anosmic individuals, we investigated the neural BOLD responses in the olfactory cortices following two odor stimuli, rose and eucalyptus, by using a 3T MR scanner. Comparing the two groups, we observed a network of brain areas being more active in the normal individuals when smelling the odors. In addition, a number of brain areas also showed an activation decline during the odor stimuli, which is hypothesized as a resource allocation deactivation. This study illustrated alterations in the brain activity between the normal individuals and anosmic patients when smelling odors, and could potentially help for a better anosmia diagnosis in the future.

Acute respiratory viruses (ARVs) are leading cause of diseases in human worldwide. High risk individuals including children and elderly could potentially develop severe illness that could result in hospitalization or death in the worst case. Most common ARVs are Human respiratory syncytial virus, Human Metapneumovirus, Human Parainfluenza Virus, rhinovirus, coronaviruses (including SARS and MERS CoV), adenoviruses, Human Bocavirus, enterovirus (-D68 and 71), and influenza viruses. The olfactory deficits due to ARVs infection is a common symptom among patients. This mini review provides an overview of the role of SARS-CoV-2 and other common ARVs in the development of human olfactory pathophysiology. We highlight the critical need for understanding the signaling underlying the olfactory dysfunction and the development of therapeutics for this wide-ranging category of AVRs to restore the altered or loss of smell in affected patients.

Over the course of the pandemic due to the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), multiple new clinical manifestations, as the consequence of the tropism of the virus, have been recognized. That includes now the neurological manifestations and conditions, such as headache, encephalitis, as well as olfactory and taste disorders. We present a series of ten cases of RT-PCR confirmed SARS-CoV-2 infected patients diagnosed with viral-associated olfactory and taste loss from four different countries.

Background Olfactory perception is an important physiological function for the human well-being and health. Loss of olfaction, or anosmia, caused by viral infections such as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) received a considerable attention especially in the persistent cases that take long time to recover. Objectives This review discusses the integration of different components of the olfactory epithelium to serve as a structural and functional unit, and explores how they are affected during viral infections, leading to the development of olfactory dysfunction. Methods The review mainly focused on the role of receptors mediating the disruption of olfactory signal transduction pathways such as ACE2, TMPRSS2 protease, neuropilin 1 (NRP1), basigin (CD147), olfactory, TRPV1, purinergic, and interferon gamma receptors. Furthermore, the compromised function of the epithelial sodium channel (ENaC) induced by SARS-CoV-2 infection and its contribution in olfactory dysfunction is also discussed. Results Collectively, this review provides fundamental information about the many types of receptors that may modulate olfaction and participate in olfactory dysfunction. It will help to understand the underlying pathophysiology of virus-induced anosmia which may help in finding and designing effective therapies targeting molecules involved in viral invasion and in olfaction. Conclusion This wide and complex spectrum of receptors that mediates the pathophysiology of olfactory dysfunction reflects the many ways by which anosmia can be therapeutically managed.

SARS-CoV-2 (CoV-2) is a coronavirus which is causing the actual COVID-19 pandemic. The disease caused by 2019 new coronavirus (2019-nCoV) was named coronavirus disease-19 (COVID-19) by the World Health Organization in February 2020. Primary non-specific reported symptoms of 2019-nCoV infection at the prodromal phase are malaise, fever, and dry cough. The most commonly reported signs and symptoms are fever (98%), cough (76%), dyspnea (55%), and myalgia or fatigue (44%). Nonetheless, recent reports suggest an association between COVID-19 and altered olfactory and taste functions, although smell seems to be more affected than taste. These associations of smell and taste dysfunctions and CoV-2 are consistent with case reports describing a patient with SARS with long term anosmia after recovery from respiratory distress, with the observation that olfactory function is commonly altered after infection with endemic coronaviruses, and with data demonstrating that intentional experimental infection of humans with CoV-299 raises the thresholds at which odors can be detected. Post-viral anosmia and is one of the leading causes of loss of sense of smell in adults, accounting for up to 40% cases of anosmia. Viruses that give rise to the common cold are well known to cause post-infectious loss, and over 200 different viruses are known to cause upper respiratory tract infections. I reviewed the possible mechanisms of smell and taste loss in COVID-19. I concluded that since the existence of such a relationship is likely, it is highly recommended that those patients who experience complications such as smell and/or taste loss, even as unique symptoms, should be considered as potential SARS-CoV-2 virus carriers.

At present Coronavirus disease-2019 (COVID-19) is one of the leading contributing factor to mortality and the impact of the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection on the sinonasal tract has become more prominent, particularly with the rising awareness of olfactory dysfunction (OD). We extracted data from published papers available in electronic databases (Wiley online library, PubMed, and Nature). We used the following search terms alone or with combinations - Olfactory dysfunction, SARS-CoV-2, mechanism and treatments. We found worldwide up to 98% of patients confirmed OD due to COVID-19. Current studies have implied that regardless of the high self-reported recovery rate, 25–40% of patients after 1 or 2 months and approximately 15%–28% of patients at six months struggle to fully restore their sense of smell. Moreover, female sex, younger and older age, active smoking, and chronic lung disease are reported as the associated risk factors of OD. Although the pathophysiological mechanism of action(s) of the OD is yet to be explored in depth, central nervous system (CNS) entrance, olfactory bulb (OB) and sustentacular cell damage, neural routes inflammation, non-neuronal cells damage, decreased OB volume and deregulation of olfactory receptor genes are among the commonly reported mechanisms for the development of OD.

Objective: To describe technique of platelet rich plasma injection into the olfactory cleft in patients with long-term COVID-19 olfactory dysfunction. Methods: The technique starts with the blood extraction and the isolation of PRP through a 10-min centrifugation (4,200 rpm). The supernatant was injected in nasal regions with a 27-G needle after a local anesthesia with Xylocain 10% spray. The injection was performed through a 0° rigid optic. Precisely, several points of 0.2–0.5 mL were performed in the nasal septum in regard of the head of the middle turbine, and in the head of the middle turbine in both sides. Clinical, psychophysical and pain outcomes were evaluated pre- to post-injection. Results: A 22-year-old female with 24-month post-COVID-19 anosmia was recruited for the injection of PRP. The olfactory cleft endoscopic scale score was 0 and the threshold, discrimination and identification scores were 1, 8 and 0, respectively. The Olfactory Disorder Questionnaire score was 51. The patient benefited from the injection of 2.2 mL of PRP in nasal regions, which was done without complication. The procedure pain level was 2/10, while the local anesthesia with xylocaine 10% was judged as the most annoyance step with a score of 3/10. At 2-month post-injection, the TDI scores reached 16, 16, and 16 (48), while the Olfactory Disorder Questionnaire was 73. The patient described its recovery as very rapid, lasting 3-4 days, and occurring 3-week post-injection. Conclusion: The injection of PRP into the olfactory cleft is a safe and easiness new approach that may improve the recovery of smell sense.

Background: Cancer patients may fail to distinguish COVID-19 symptoms such as anosmia, dysgeusia/ageusia, anorexia, headache, and fatigue, which are frequent after cancer treatments. We aimed to identify symptoms associated with COVID-19 and to assess the strength of their association in cancer and cancer-free populations. Methods: The prospective multicenter cohort study PAPESCO-19 included 878 cancer patients and 940 healthcare workers (HCWs) systematically tested for SARS-CoV-2-specific antibodies. Participants reported the results of routine screening RT-PCR and thirteen COVID-19 symptoms. Backward logistic regression identified the symptom combinations significantly associated with COVID-19. Results: COVID+ proportions were similar in patients (8%) and HCWs (9.5%, p=0.26), whereas symptomatic proportions were lower in patients (32%) than HCWs (52%, p<0.001). Anosmia, anorexia, fever, headache, and rhinorrhea together accurately discriminated (c-statistic=0.7027) COVID-19 cases in patients. Anosmia, dysgeusia/ageusia, muscle pain, intense fatigue, headache, and chest pain better discriminated (c-statistic=0.8830) COVID-19 cases in HCWs. Anosmia had the strongest association in patients (OR=7.48, 95% CI: 2.96–18.89) and HCWs (OR=5.71, 95% CI: 2.21–14.75). Conclusions: COVID-19 symptoms and their diagnostic performance differ in cancer patients and HCWs. Anosmia is associated with COVID-19 for patients, while dysgeusia/ageusia are not. Cancer patients deserve tailored preventive measures due to their particular COVID-19 symptom pattern.

Early detection, isolation, and management of COVID-19 patients are crucial to contain the current pandemic. The CDC in USA recently included "sudden loss of taste (dysgeusia/ageusia) and smell (anosmia/hyposmia)” as symptoms of COVID-19. If these symptoms are reliable forerunner symptoms of COVID-19, then it may facilitate early detection and containment of the disease. Hence, we systematically evaluated the contemporary evidence on dysgeusia and anosmia as trigger symptoms in COVID-19. Ovid MEDLINE, EBSCO host, and Web of Science databases were searched between December 25, 2019-May 30, 2020.Of the 13 identified records, eight (totaling 11,054 COVID-19 patients), were included, as per the selection criteria. The studies emanated mostly from the European community, as well as China, the USA, and Iran. In total, anosmia and dysgeusia symptoms were present in 74.9 % and 81.3% ambulatory as well as hospitalized, mild-to-severe cases of COVID-19 patients, respectively. The European, US, and Iran data indicate that olfactory, and gustatory symptoms appear prior to general COVID-19 symptoms in a majority of the patients. To our knowledge, this is the first systematic review analyzing the prevalence of chemosensory dysfunction in COVID-19. Further, studies are essential to evaluate their utility as harbingers of COVID-19 onset, and to establish clinical practice guidelines.