[Interpretation of the 2021 American Academy of Allergy, Asthma and Immunology expert consensus on the treatment of postinfectious olfactory dysfunction].

Respiratory tract viruses are the second leading cause of olfactory dysfunction. Between 2019 to 2022, the world has been plagued by the problem of olfaction caused by the COVID-19. As we learn more about the impact of severe acute respiratory syndrome coronavirus 2（SARS-CoV-2）, with the recognition that olfactory dysfunction is a key symptom of this disease process, there is a greater need than ever for evidence-based management of postinfectious olfactory dysfunction（PIOD）. The Clinical Olfactory Working Group has proposed theconsensus on the roles of PIOD. This paper is the detailed interpretation of the consensus.

Parosmia and altered taste in patients recovering from Covid 19.

Parosmia is a well-documented consequence of smell loss associated with Covid 19. Those who experience this qualitative olfactory disorder during recovery find that the odour of common foods and household items is distorted, and the experience can range from merely altered to profoundly disgusting. This can lead to a greatly altered relationship with food, including the physical symptoms of loss of appetite, nausea, vomiting, as well as wider reaching issues such as withdrawal from social situations, emotional distancing from others in their close social circles, and anhedonia. There is at present no known cure or intervention to mitigate the condition. The AbScent Parosmia and Phantosmia support group on Facebook became an important resource for patients with this condition during the early part of the pandemic, and the crowd-sourcing of experiences, tips and peer-to-peer advice became a valuable source of information for the community as well as researchers trying to understand the condition. Using protocols described in earlier literature on the use of social media for qualitative research, this paper provides information on the management of parosmia based on the experiences of over 30k patients in the AbScent Parosmia and Phantosmia group on Facebook and 6k member of the AbScent Network.

Parosmia and COVID-19 from the lens of google trends: infodemiology study

Parosmia is a subcategory of olfactory hallucinations and refers to a distorted ability to detect the right smell in the presence of a stimulus. The study aims to investigate the relationship between COVID-19 and parosmia by calculating the interest search volume of parosmia using google trends. Google trends was used to investigate trends in searches regarding parosmia and to track these search engine terms against the coronavirus outbreak in France, Sweden, the United States [USA], and Turkiye. The terms utilized in the search were "Parosmia" and "anosmia" and the data were collected between March 20, 2020, to July 25, 2021. Parosmia searches increase with time in all the countries and the correlation significance values were obtained for France, Sweden, USA, and Turkiye to be Rs 0.660, P-value 0.0038 "Moderate correlation";Rs 0.566, P-value 0.017 "Moderate correlation";Rs 0.842, P-value 0.0001 "Strong correlation";Rs 0.800, P-value 0.0001" Strong correlation" respectively. Relative search volume of parosmia and anosmia changed significantly with time may point out that there are some late COVID-19 complications that haven't been detected yet, and with the pandemic still ongoing, more complications could be discovered by analyzing the trends.Copyright © 2023, Istanbul Medipol University. All rights reserved.

Impairment of quality of life due to COVID-19-induced long-term olfactory dysfunction.

Introduction: Olfactory dysfunction is one of many long-lasting symptoms associated with COVID-19, estimated to affect approximately 60% of individuals and often lasting several months after infection. The associated daily life problems can cause a decreased quality of life. Methods: Here, we assessed the association between perceived quality of life and both qualitative and quantitative olfactory function (distorted and weakened sense of smell, respectively) in 58 individuals who had undergone confirmed SARS-CoV-2 infection and who complained about olfactory dysfunction. Results: Participants with large quantitative olfactory dysfunction experienced a greater reduction in their quality of life. Moreover, our participants had a high prevalence of qualitative olfactory dysfunction (81%) with a significant correlation between qualitative olfactory dysfunction and daily life impairment. Strong drivers of low quality of life assessments were lack of enjoyment of food as well as worries related to coping with long-term dysfunctions. Discussion: These results stress the clinical importance of assessing qualitative olfactory dysfunction and the need to develop relevant interventions. Given the poor self-rated quality of life observed, healthcare systems should consider developing support structures, dietary advice, and guidelines adapted to individuals experiencing qualitative olfactory dysfunction.

Food-related experiences and behavioral responses among people affected by chemosensory dysfunctions following COVID-19: A scoping review.

A category of symptoms that became characteristic early in the first wave of the coronavirus disease 2019 (COVID-19) pandemic was chemosensory dysfunctions (alterations of smell and taste). Such symptoms substantially affect food and eating-cornerstones for both nutrition-related health outcomes and for quality of life. Based on this, this scoping review aimed to map out existing scientific literature on food-related experiences and related behavioral responses among people affected by chemosensory dysfunctions following COVID-19. A librarian-supported search of PsycInfo, PubMed, and Scopus for publications written in English (2020 to April 26, 2022) was conducted. Two authors searched for and screened publications and three others extracted and collated data. These are reported following the Preferred Reporting Items of Systematic reviews and Meta-Analyses extension for Scoping Reviews. Of 1169 hits, 9 publications were included in the review. The results are thematized as "Psychological and social aspects" and "Nutritional aspects," each with the subsections "Experiences" and "Behavioral responses." A great variety of food-related problems, nutritional and mental health effects, and implications for social life are identified. People affected by chemosensory dysfunctions following COVID-19 suffer, as evident both in stories from qualitative studies and in measurements of quality of life. The results impact all professions who are and may come to be involved in treating these patients, such as nurses, physicians, dietitians, and psychologists. With more knowledge about the dysfunctions' manifestation, duration, and impact on everyday life, multiprofessional teams need to collaborate in supporting patients medically, psychosocially, and nutritionally.

Changes in olfaction and taste in patients hospitalized for COVID-19 and their relationship to patient evolution during hospitalization.

OBJECTIVES: During the COVID-19 pandemic, several cases of changes in olfaction and taste associated with the infection have been reported. Therefore, otolaryngologists are frequently the first medical professionals sought by patients. The aim of this study was to evaluate the frequency of olfaction and taste disorders in patients hospitalized with COVID-19, and their association with other clinical manifestations and patient evolution during hospitalization. METHODS: 248 patients, admitted to three public hospitals in Belo Horizonte, Minas Gerais, Brazil, were prospectively included: Hospital das Clínicas da Universidade Federal de Minas Gerais (HC-UFMG), Hospital Júlia Kubitschek (HJK) and Hospital Eduardo de Menezes (HEM), who, upon admission to hospital, presented with Severe Acute Respiratory Syndrome due to COVID-19. Clinical and laboratory variables and outcomes during hospitalization were prospectively collected from the electronic medical records. The collection of sociodemographic and symptomatology data during the acute phase was carried out prospectively in electronic medical records and confirmed with the patients at a subsequent outpatient visit. RESULTS: The most frequently reported symptoms were dyspnea (77.4%), cough (69.8%) and fever (55.2%). During the acute phase of the disease, 95 (38.3%) and 87 (35.1%) patients reported taste and olfaction disorders, respectively. There was a lower prevalence of dysosmia among patients with previous comorbidities (p < 0.05). Both symptoms were associated with less need for intensive care admission (p = 0.001 for dysgeusia and p = 0.021 for dysosmia) and a negative correlation with length of hospital stay (dysosmia: r = -0.175, p < 0.05; dysgeusia: r = -0.29, p < 0.001) and length of stay in the ICU (dysosmia: r = -0.136, p < 0.05; dysgeusia: r = -0.215, p < 0.05). The absence of taste disorders was also associated with a greater need for mechanical ventilation (p < 0.001). CONCLUSION: Changes in taste and olfaction were reported by a large number of patients in the acute phase of COVID-19. In this study, both were markers of better clinical patient evolution. LEVEL OF EVIDENCE: 1B.

Post-COVID Parosmia in Women May be Associated with Low Estradiol Levels.

We aimed to investigate the effects of female gender hormones on post-COVID parosmia in females. Twenty-three female patients aged 18-45 who had COVID-19 disease in the last 12 months were included in the study. Estradiol (E2), prolactin (PRL), luteotrophic hormone (LH), follicular stimulating hormone (FSH), and thyroid stimulating hormone (TSH) values were measured in the blood of all participants and a parosmia questionnaire was applied for the subjective evaluation of olfactory function. Values between 4 and 16 were obtained as parosmia score (PS), and the lowest PS showed the most severe complaint. The mean age of the patients was 31 (18-45). According to the PS, patients with a score of 10 or less were classified as Group 1, and patients above 10 were considered Group 2. The age difference between Groups 1 and 2 was statistically significant and younger patients were found to have more complaints of parosmia (25 and 34, respectively, p-value 0.014). It was found that patients with severe parosmia had lower E2 values and there was a statistically significant difference (p-value 0.042) between groups 1 and 2 in terms of E2 values (34 ng/L and 59 ng/L, respectively). There was no significant difference between the two groups in terms of PRL, LH, FSH, TSH levels, or FSH/LH ratio. It may be recommended to measure E2 values in female patients whose parosmia continues after COVID-19 infection. Supplementary Information: The online version contains supplementary material available at 10.1007/s12070-023-03612-9.

Psychophysical assessment of olfactory and gustatory function in post-mild COVID-19 patients: A matched case-control study with 2-year follow-up.

BACKGROUND: The aim of this study was to psychophysically evaluate the prevalence of smell and taste dysfunction 2 years after mildly symptomatic severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) infection compared to that observed at 1-year follow-up and while considering the background of chemosensory dysfunction in the no-coronavirus disease 2019 (COVID-19) population. METHOD: This is a prospective case-control study on 93 patients with polymerase chain reaction (PCR)-positive SARS-CoV-2 infection and 93 matched controls. Self-reported olfactory and gustatory dysfunction was assessed by 22-item Sino-Nasal-Outcome Test (SNOT-22), item "Sense of smell or taste." Psychophysical orthonasal and retronasal olfactory function and gustatory performance were estimated using the extended Sniffin' Sticks test battery, 20 powdered tasteless aromas, and taste strips test, respectively. Nasal trigeminal sensitivity was assessed by sniffing a 70% solution of acetic acid. RESULTS: The two psychophysical assessments of chemosensory function took place after a median of 409 days (range, 366-461 days) and 765 days (range, 739-800 days) from the first SARS-CoV-2-positive swab, respectively. At 2-year follow-up, cases exhibited a decrease in the prevalence of olfactory (27.9% vs. 42.0%; absolute difference, -14.0%; 95% confidence interval [CI], -21.8% to -2.6%; p = 0.016) and gustatory dysfunction (14.0% vs. 25.8%; absolute difference, -11.8%; 95% CI, -24.2% to 0.6%; p = 0.098). Subjects with prior COVID-19 were more likely than controls to have an olfactory dysfunction (27.9% vs. 10.8 %; absolute difference, 17.2%; 95% CI, 5.2% to 28.8%) but not gustatory dysfunction (14.0% vs. 9.7%; absolute difference, 4.3%; 95% CI, -5.8% to 14.4% p = 0.496) still 2 years after the infection. Overall, 3.2% of cases were still anosmic 2 years after the infection. CONCLUSIONS: Although a proportion of subjects recovered from long-lasting smell/taste dysfunction more than 1 year after COVID-19, cases still exhibited a significant excess of olfactory dysfunction 2 years after SARS-CoV-2 infection when compared to matched controls.

Olfactory Training Impacts Olfactory Dysfunction Induced by COVID-19: A Pilot Study.

INTRODUCTION: Olfactory dysfunction is one of the main symptoms of COVID-19 and may last beyond resolution of the infection. The most promising intervention for post-viral olfactory dysfunction is olfactory training (OT), which involves exposing the olfactory system to a range of odors daily. This approach is thought of promoting the regeneration of olfactory receptor cells, but its effectiveness in patients with post-COVID-19 olfactory dysfunction has yet to be confirmed. METHODS: This double-blind randomized pilot study compared the effectiveness of OT versus placebo in the treatment of post-COVID-19 olfactory dysfunction. Twenty-five participants were recruited in each group. OT protocol consisted of sniffing 4 scents (rose, orange, clove, and eucalyptus) for 5 min twice daily for 12 weeks. Olfactory function was assessed before and after the training using (1) a validated odor identification test (UPSIT-40) and (2) a 10-point visual analog scale; we further assessed the presence of (3) parosmia. RESULTS: While we did not observe any effect of OT on olfactory test scores, we observed a significant improvement of subjective olfactory function in the intervention group, while no such effect was observed in the placebo group. Finally, the frequency of parosmia was significantly lower in the intervention group. CONCLUSIONS: This study highlights an increase in subjective but not objective olfactory function when performing OT for 12 weeks. Further, parosmia seems to be positively affected by OT. These results may serve as a starting point for larger scale studies to assess the efficacy of OT for treatment of post-COVID-19 olfactory dysfunction.

Phantom smells: a prevalent COVID-19 symptom that progressively sets in.

PURPOSE: One of the long-term symptoms of COVID-19 is phantosmia, a type of Olfactory Disorder (OD) that has deleterious impacts on patients' quality of life. The aim of this article was to study how this poorly understood qualitative OD manifests itself in the COVID-19. METHODS: 4691 patients with COVID-19 responded to our online questionnaire focusing on COVID-19-related OD. We first analyzed the prevalence of phantosmia in this population. Then, with the help of Natural Language Processing techniques, we investigated the qualitative descriptions of phantom smells by the 1723 respondents who reported phantosmia. RESULTS: The prevalence of phantosmia was of 37%. Women were more likely to report phantosmia than men, as well as respondents for whom OD was described as fluctuating rather than permanent, lasted longer, was partial rather than total and appeared progressively rather than suddenly. The relationship between OD duration and phantosmia followed a logarithmic function, with a prevalence of phantosmia increasing strongly during the first 2 months of the disease before reaching a plateau and no decrease over the 15 months considered in this study. Qualitative analyses of phantosmia descriptions with a sentiment analysis revealed that the descriptions were negatively valenced for 78% of the respondents. Reference to "tobacco" was more frequent in non-smokers. Source names and odor characteristics were used differently according to age and OD duration. CONCLUSION: The results of this descriptive study of phantosmia contribute to the current efforts of the medical community to better understand and treat this rapidly increasing COVID-19-related OD.

The Correlation between the Results of the Sniffin' Sticks Test, Demographic Data, and Questionnaire of Olfactory Disorders in a Hungarian Population after a SARS-CoV-2 Infection.

BACKGROUND: After a severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection, smell disorders frequently occur, significantly affecting patients' quality of life (QoL). METHODS: 110 patients with persistent olfactory disorder after coronavirus infection were enrolled. These patients underwent chemosensory testing using the Sniffin' Sticks test, and completed the Questionnaire of Olfactory Disorders (QOD). RESULTS: 30% of the patients reported anosmia, and 70% reported hyposmia. Upon comparing subjective and chemosensory testing categories, good category matching was observed in 75.3% (i.e., anosmia based on both methods in 10 and hyposmia in 48 cases). Statistical analysis using the Chi-square test revealed a significant result (p = 0.001 *). Between the TDI (i.e., Threshold, Discrimination, Identification) results of the three subjective report groups (i.e., hyposmia, anosmia, and parosmia), no significant differences were observed. When the TDI and QOD results were compared, no consistent significant correlations were found in most TDI and QOD outcomes. Between the TDI and Scale 2 results, a significant, although slight correlation was observed by the Spearman's (rho = 0.213, p = 0.027 *) and Pearson's (rho = 0.201, p = 0.037 *) tests. CONCLUSIONS: The nonsignificant correlation between objective and subjective methods suggests that these results should be interpreted independently. Moreover, adequate management is essential even in mild cases.

Randomized Clinical Trial Comparing Insulin Fast Dissolving Films versus Control Group for Anosmic Patients for Improving Their Health and Social Qualities of Life

Background: Olfactory anomalies are the most common diseases among post-COVID-19 disorders. Only 15% of patients completed their prescribed treatment plans, even though several different treatment strategies were recommended;this had a detrimental effect on the patients' physical, social, and emotional wellbeing.Purpose: The aim of this study was approving intranasal fast-dissolving insulin films as the treatment of choice for anosmia in comparison to the control group, and the innovative treatment for anosmic post-COVID-19 is assessed in terms of the patients' health-related quality of life (HRQoL).Methods: For therapy and evaluation, a randomized clinical trial with forty adult anosmic post-viral patients was performed. The recruited participants were recruited between October 1 and March 8 of 2021 based on predetermined criteria. A validated smell assessment questionnaire concerning the participants' olfactory, physical, and psychological outcomes was given to them. Recruited patients were randomly subdivided into two groups: intervention and control group. Intervention was treated with insulin intranasal films, while control group took plain films (placebo).Results: The physical, emotional, and social health quality of life were significantly (p-value <0.0001) improved after 4 consecutive weeks of treatment with the intervention group compared to the control group. The data were analyzed statistically with the aid of GraphPad Prism 9.1.0.Conclusion: The lowest HRQoLs, which significantly impact their quality of life, are found in post-COVID-19 anosmic patients treated with insulin films. It is advised to employ this new intervention (insulin films) as the main therapy approach and to gather additional industry data for its development and dissemination. Problems with self-hygiene, eating, sense of danger and emotional satisfaction were significantly enhanced with insulin intervention versus placebo.

A New Mystery: Phantosmia after COVID-19 Infection.

Coronavirus disease 2019 (COVID-19) has developed as a pandemic and has caused millions of deaths worldwide. Multiple studies have implicated anosmia and ageusia as symptoms associated with COVID-19. In this case report we present the cases who suffer from phantosmia after COVID-19 infection. As the prevalence of the virus increases, the symptomatology profile continues to be updated. More studies are needed to better understand this disease.

Analysis of Prevalence and Predictive Factors of Long-Lasting Olfactory and Gustatory Dysfunction in COVID-19 Patients.

BACKGROUND: Although smell and taste disorders are highly prevalent symptoms of COVID-19 infection, the predictive factors leading to long-lasting chemosensory dysfunction are still poorly understood. METHODS: 102 out of 421 (24.2%) mildly symptomatic COVID-19 patients completed a second questionnaire about the evolution of their symptoms one year after the infection using visual analog scales (VAS). A subgroup of 69 patients also underwent psychophysical evaluation of olfactory function through UPSIT. RESULTS: The prevalence of chemosensory dysfunction decreased from 82.4% to 45.1% after 12 months, with 46.1% of patients reporting a complete recovery. Patients older than 40 years (OR = 0.20; 95% CI: [0.07, 0.56]) and with a duration of loss of smell longer than four weeks saw a lower odds ratio for recovery (OR = 0.27; 95% CI: [0.10, 0.76]). In addition, 28 patients (35.9%) reported suffering from parosmia, which was associated with moderate to severe taste dysfunction at the baseline (OR = 7.80; 95% CI: [1.70, 35.8]). Among the 69 subjects who underwent the UPSIT, 57 (82.6%) presented some degree of smell dysfunction, showing a moderate correlation with self-reported VAS (r = -0.36, p = 0.0027). CONCLUSION: A clinically relevant number of subjects reported persistent chemosensory dysfunction and parosmia one year after COVID-19 infection, with a moderate correlation with psychophysical olfactory tests.

Pathogenesis of Olfactory Disorders in COVID-19.

Since the outbreak of the SARS-CoV-2 pandemic, olfactory disorders have been reported as a frequent symptom of COVID-19; however, its pathogenesis is still debated. The aim of this review is to summarize the current understanding of the pathogenesis of smell impairment in the course of COVID-19 and to highlight potential avenues for future research on this issue. Several theories have been proposed to explain the pathogenesis of COVID-19-related anosmia, including nasal obstruction and rhinorrhea, oedema of the olfactory cleft mucosa, olfactory epithelial damage either within the olfactory receptor cells or the supporting non-neural cells (either direct or immune-mediated), damage to the olfactory bulb, and impairment of the central olfactory pathways. Although the pathogenesis of COVID-19-related anosmia is still not fully elucidated, it appears to be mainly due to sensorineural damage, with infection of the olfactory epithelium support cells via the ACE1 receptor and disruption of the OE caused by immense inflammatory reaction, and possibly with direct olfactory sensory neurons infection mediated by the NRP-1 receptor. Involvement of the higher olfactory pathways and a conductive component of olfactory disorders, as well as genetic factors, may also be considered.

Patterns of self-reported recovery from chemosensory dysfunction following SARS-CoV-2 infection: insights after 1 year of the pandemic.

BACKGROUND: The coronavirus disease (COVID-19), due to the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), causes chemosensory dysfunction. AIMS/OBJECTIVES: To determine the characteristics of chemosensory dysfunction and to identify factors associated with chemosensory complete recovery and time to recovery. MATERIALS AND METHODS: This cross-sectional study included all patients presenting with chemosensory dysfunction and confirmed SARS-CoV-2 infection from May to August 2020 who underwent telemedicine follow-up after 1 year to assess their chemosensory recovery. RESULTS: A total of 372 patients were included, of which 53.8% were male. The mean age ± SD was 37.45 ± 13.44. The majority experienced combined (olfactory and gustatory) dysfunction (85.7%), and 315 patients (84.7%) had complete loss of chemosensory function. The independent predictors associated with a low likelihood of complete recovery were parosmia (aOR 0.16, p < .001), upper respiratory tract symptoms (aOR 0.28, p = .001), and dyspnoea (aOR 0.21, p < .001), whereas the factors associated with a long recovery period were parosmia (aOR 12.04, p = .002), headache (aOR 7.19, p = .007), and hypertension (aOR 7.76, p = .039). CONCLUSIONS: A full recovery outcome was predominant. The presence of parosmia was linked to both an incomplete recovery and a long time to recovery. SIGNIFICANCE: Parosmia and respiratory symptoms are implicated in the incomplete recuperation of chemosensory function.

The Effects of Persistent Olfactory and Gustatory Dysfunctions on Quality of Life in Long-COVID-19 Patients.

(1) Background: Persistent olfactory (POD) and gustatory (PGD) dysfunctions are one of the most frequent symptoms of long-Coronavirus Disease 2019 but their effect on the quality of life (QoL) of patients is still largely unexplored. (2) Methods: An online survey was administered to individuals who reported to have had SARS-CoV-2 infection at least 6 months prior with persisting COVID-19 symptoms (using the COVID symptom index), including ratings of POD and PGD, and their physical (PCS) and mental (MCS) components of quality of life were assessed using the standardized short form 12 questionnaire (SF-12). (3) Results: Responses from 431 unique individuals were included in the analyses. The most frequent persistent symptoms were: fatigue (185 cases, 42.9%), olfactory dysfunction (127 cases, 29.5%), gustatory dysfunction (96 cases, 22.3%) and muscle pain (83 cases, 19.3%). Respondents who reported persisting muscle pain, joint pain, fatigue, headache, gastrointestinal disturbances, and dyspnea had significantly worse PCS. Those experiencing persistent fatigue and dyspnea also showed significantly lower MCS. Respondents reporting POD or PGD showed significantly worse QoL, but only pertaining to the MCS. Multiple regressions predicted MCS based on olfactory and marginally on gustatory ratings, but not PCS. Age significantly affected the prediction of PCS but not MCS, and gender and temporal distance from the COVID-19 diagnosis had no effect. (4) Conclusions: POD and PGD are frequent symptoms of the long-COVID-19 syndrome and significantly reduce QoL, specifically in the mental health component. This evidence should stimulate the establishment of appropriate infrastructure to support individuals with persistent CD, while research on effective therapies scales up.