Prevalence of anosmia and ageusia symptoms among long-term effects of COVID-19

COVID-19 Oral Sequelae: Persistent Gustatory and Saliva Secretory Dysfunctions after Recovery from COVID-19

Diverse manifestations have been recognized to last for a long time in patients infected with SARS-CoV-2. However, understanding of oral sequelae after recovery from COVID-19 is relatively poor compared to that of oral symptoms in the acute phase of COVID-19 and other COVID-19 sequelae. The aim of the present study was to characterize persistent gustatory and saliva secretory dysfunctions and to speculate on their pathogenic mechanisms. Articles were retrieved by searching scientific databases with a cutoff date of September 30, 2022. The literature search indicated that ageusia/dysgeusia and xerostomia/dry mouth are reported by 1-45% of COVID-19 survivors at follow-ups of 21-365 days and by 2-40% of COVID-19 survivors at follow-ups of 28-230 days, respectively. The prevalence of gustatory sequelae partly depends on difference in ethnicity, gender, age, and disease severity of subjects. Co-occurring gustatory and saliva secretory sequelae are pathogenically related to either or both of the following: expression of SARS-CoV-2 cellular entry-relevant receptors in taste buds and salivary glands, and SARS-CoV-2 infection-induced deficiency in zinc that is essential for normality of taste perception and saliva secretion. Given the long-term oral sequelae, hospital discharge is not the end of the disease; therefore, careful attention should be continuously paid to oral conditions of post-COVID-19 patients.

Efficacy of Stellate Ganglion Block in Treating Long-Term COVID-19-Related Olfactory and Gustatory Dysfunction: A Case Series

Olfactory and gustatory dysfunction, including anosmia, parosmia, ageusia, and dysgeusia, are common long-term symptoms of coronavirus disease 2019 (COVID-19) infection. These symptoms can have a severe impact on quality of life of a patient, including psychological well-being. Stellate ganglion block (SGB) has recently been explored as a potential therapeutic intervention for these symptoms. In this case series, we present six patients with long-term COVID-19 symptoms and we detail how their symptoms evolved after an SGB. All SGB were performed under ultrasound guidance by the same physician. Patients had a right SGB during the initial visit, followed by a left SGB at a subsequent visit. All but one patient reported improvements in olfaction and gustation after the SGB. Our findings suggest that SGB may be a promising therapeutic intervention for patients with olfactory and gustatory dysfunction related to long-term COVID-19 symptoms. Further research is needed to confirm these findings and to explore the optimal treatment protocol.

Prevalence of Chemosensitive Neurological Disorders of Smell and Taste and Association with Blood Groups in SARS-CoV-2 Patients: Cross-Sectional Study

The Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) has caused a highly challenging and threatening situation worldwide. SARS-CoV-2 patients develop various clinical symptoms. The olfactory and taste dysfunctions are potential neurological manifestations among SARS-CoV-2 patients; however, their relationship with blood groups has rarely been investigated. This study aimed to investigate the prevalence of chemosensitive neurological disorders of smell and taste and their association with blood groups in SARS-CoV-2 patients. The present cross-sectional study was performed in the Department of Pathology, and Physiology, College of Medicine, King Saud University, Riyadh, Saudi Arabia. A well-structured, self-administered questionnaire was designed and distributed through social media platforms. A total of 922 Saudi and non-Saudi adults aged 18 years or older participated in the study. Out of 922 participants, the number of people who had anosmia was 309 (33.5%), 211 (22.9%) had hyposmia, and 45 (4.8%) had dysosmia. Moreover, 180 (19.52%) had ageusia, 47 (5.1%) and 293 (31.8%) had hypogeusia and dysgeusia, respectively. Among all the participants, 565 (61.27%) had smell-related disorders and 520 (56.39%) participants had taste-related clinical symptoms. The occurrence of anosmia and ageusia was relatively high among females compared to males (p = 0.024). The prevalence of smell-related disorders was 25.0% (230) and taste-related disorders was 23.21% (214) among the study participants with blood group O compared to all other blood group (A, B, and AB) participants who have smell allied disorders 30.69% (283), and taste allied disorders 27.98% (258). The prevalence of chemosensitive neurological disorders involving impaired smell and taste was higher in SARS-CoV-2 patients. These clinical symptoms were common among the participants with blood group type O compared to all other ABO blood group types. The role of certain demographic characteristics was consistent throughout multiple studies, notably with female gender and young adults.

Treatments of COVID-19-Associated Taste and Saliva Secretory Disorders

Since the worldwide spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, treating taste and saliva secretory disorders associated with coronavirus disease 2019 (COVID-19) has become a critical issue. The aim of the present study was to update information on treatments applicable to such oral symptoms and discuss their pathogenic mechanisms. The literature search indicated that different treatments using tetracycline, corticosteroids, zinc, stellate ganglion block, phytochemical curcumin, traditional herbal medicine, nutraceutical vitamin D, photobiomodulation, antiviral drugs, malic acid sialagogue, chewing gum, acupuncture, and/or moxibustion have potential effects on COVID-19-associated ageusia/dysgeusia/hypogeusia and xerostomia/dry mouth/hyposalivation. These treatments have multiple modes of action on viral cellular entry and replication, cell proliferation and differentiation, immunity, and/or SARS-CoV-2 infection-induced pathological conditions such as inflammation, cytokine storm, pyroptosis, neuropathy, zinc dyshomeostasis, and dysautonomia. An understanding of currently available treatment options is required for dental professionals because they may treat patients who were infected with SARS-CoV-2 or who recovered from COVID-19, and become aware of their abnormal taste and salivary secretion. By doing so, dentists and dental hygienists could play a crucial role in managing COVID-19 oral symptoms and contribute to improving the oral health-related quality of life of the relevant patients.

Diode laser in management of loss of taste sensation in patients with post-COVID syndrome: a randomized clinical trial

OBJECTIVE

Loss of taste (ageusia) is a symptom observed following recovery from COVID-19 infection. The loss of taste and smell sensation may negatively affect patients' quality of life (QoL). The present study aimed to evaluate the effectiveness of the Diode Laser in managing loss of taste sensation in patients with post-COVID syndrome versus the placebo.

MATERIAL AND METHOD

The study sample was 36 patients who complained of persistent loss of taste sensation following COVID-19. The patients were randomly assigned to one of the two groups according to the received treatment: Group I (laser treatment) and Group II (light treatment), with each patient receiving a diode laser treatment or placebo from the same operator. Taste sensation was subjectively measured after treatment for four weeks.

RESULTS

The results demonstrated a significant difference between both groups regarding taste restoration after one month (p = 0.041), with Group II having a significantly higher percentage of cases 7 (38.9%) with partial taste restoration. In contrast, a significantly higher proportion of Group I 17 cases (94.4%) had complete taste restoration (p < 0.001).

CONCLUSION

The present study concluded that using a Diode laser 810 nm aided in a more rapid recovery from loss of taste dysfunction.

Olfactory and Gustatory Dysfunctions Following COVID-19 Infection: Factors That Affect Their Duration in Saudi Arabia

INTRODUCTION

 Many people infected with coronavirus disease 2019 (COVID-19) have developed post-COVID-19 symptoms, which are defined as symptoms and signs (e.g., anosmia and ageusia) that persist for more than 12 weeks after getting infected with COVID-19. These symptoms may appear after or during the infection and cannot be explained by any alternative disease. In this study, we aim to investigate the factors that affect the duration of anosmia and ageusia in Saudi Arabia.

METHODS

 We conducted a nationwide, cross-sectional study using an online survey in Saudi Arabia from 14 February 2022 to 23 July 2022. The electronic survey was distributed using social media platforms, such as Twitter, WhatsApp, and Telegram.

RESULT

 The study enrolled 2497 individuals who were infected with COVID-19. A total of 60.1% of the participants showed symptoms of anosmia, ageusia, or both after getting infected with COVID-19. According to our data, we found that being a female and not having a repeated COVID-19 infection were risk factors (independent predictors) of the long duration of anosmia after COVID-19 recovery (p = <0.05). While being a male patient, a smoker, and being admitted to the ICU were risk factors (independent predictors) of long duration of ageusia after COVID-19 recovery (p = <0.05).

CONCLUSION

 In conclusion, the prevalence of chemosensory dysfunction symptoms, both olfactory and gustatory, after COVID-19 infection among the Saudi population was high. However, several factors can influence their duration, including gender, smoking, and severity of the infection.

Prevalence, Patterns, Prognosis, and Psychosocial Impact of Olfactory and Gustative Dysfunctions Among Saudi COVID-19 Patients

Objective The objective of this study is to estimate the prevalence of olfactory and gustative dysfunctions (OGD) and analyze their pattern and psychosocial impact among COVID-19 patients. Method A cross-sectional study was conducted among 194 confirmed COVID-19 cases at Al-Noor Specialist Hospital between 1 September 2020 and 30 September 2021. A questionnaire was translated and modified from another study to collect the baseline demographic data and medical history; characterization of smell and taste loss separately, including timing, level, practices or treatment used to restore, recovery, and symptom duration; and the psychological impact of OGD using six items to explore the multidimensional impact, such as daily activity, job performance, and social life. A four-point Likert-type agreement scale was used, and an impact score was calculated. Result As high as 97.4% and 94.8% of the participants declared having experienced a certain level of olfactory and gustative dysfunction, respectively. In the majority of these cases, the dysfunction occurred after the acute phase of the disease and persisted less than one month after onset. Social life (78.4%), job performance (64.4%), and daily life activities (42.8%) were the most frequently impacted dimensions, and 32% of the participants were deemed to have experienced a high psychosocial impact. Younger participants, females, and certain job categories were significantly more impacted than their counterparts. Conclusion OGDs are highly frequent in COVID-19 patients. They are described to be relatively severe and have frequent psychosocial impacts, notably in females and the younger age category. Further research is warranted to determine efficacious preventive and management strategies in order to prevent their long-term impact on wellbeing.

Impact of COVID-19 versus chronic rhinosinusitis/rhinitis associated olfactory dysfunction on health utility and quality of life

Background

Olfactory dysfunction (OD) is associated with both post-viral and inflammatory etiologies such as COVID-19 and chronic rhinosinusitis/rhinitis (CRS/R) respectively, to result in reduced quality of life (QoL). However, the former typically induces a sudden-onset OD while the latter has a gradual presentation. This study aims to establish and compare health utility values (HUVs) and olfactory-specific QoL measurements between patients with COVID-19 and CRS/R related OD.

Methods

This prospective study surveyed COVID-19 and CRS/R patients with self-reported OD using HUV assessments (EuroQol-visual analog scale [EQ-VAS], EuroQol-5 dimension [EQ-5D], time trade-off [TTO]) and olfactory and sinonasal QoL measures (questionnaire of olfactory disorders -negative and positive statements [QOD-NS + PS] and sino-nasal outcome test [SNOT-22]). A subgroup of subjects completed objective olfactory testing. Intergroup mean scores were compared using Mann-Whitney U tests.

Results

One hundred eleven subjects were enrolled: mean age ± SD (43.0 ± 15.4 years), 55.9% female. CRS/R was associated with lower HUVs as measured by EQ-VAS (CRS/R: 0.67 ± 0.18 vs. COVID-19: 0.74 ± 0.19, p = .03) and worse SNOT-22 scores in both overall (CRS/R: 49.03 ± 21.04 vs. COVID-19: 27.58 ± 18.45, p < .001) and subgroup analysis of objectively confirmed OD subjects (CRS/R: 52.40 ± 22.78 vs. COVID-19: 29.84 ± 21.10, p = .01). On the other hand, COVID-19 has greater burden on olfactory-specific QoL (QOD-NS + PS, COVID-19: 23.19 ± 13.73 vs. CRS/R: 17.25 ± 11.38, p = .04). Both groups demonstrated a similar decrease in health using the EQ-5D assessment.

Conclusion

CRS/R associated OD has a more severe impact on general health and sinonasal specific QoL outcomes, while COVID-19 associated OD has a greater burden on olfactory-specific QoL.

Level of evidence

Level 2c.

Sociodemographic Characteristics and Comorbidities of Patients With Long COVID and Persistent Olfactory Dysfunction

IMPORTANCE

Determining the characteristics, type, and severity of olfactory dysfunction in patients with long COVID is important for the prognosis and potential treatment of the affected population.

OBJECTIVE

To describe the sociodemographic and clinical features of patients with long COVID who develop persistent olfactory dysfunction.

DESIGN, SETTING, AND PARTICIPANTS

This cross-sectional study, conducted at a rehabilitation center at a public university in the Amazon region of Brazil between September 9, 2020, and October 20, 2021, comprised 219 patients with long COVID and self-reported neurologic symptoms. Of these 219 patients, 139 received a diagnosis of chronic olfactory dysfunction, as confirmed by the Connecticut Chemosensory Clinical Research Center (CCCRC) test.

EXPOSURE

Clinical diagnosis of long COVID.

MAIN OUTCOMES AND MEASURES

Electronic case report forms were prepared for the collection of sociodemographic and clinical data. Patients' sense of smell was evaluated via a CCCRC test, and the association of olfactory dysfunction with aspects of daily life was recorded using a questionnaire.

RESULTS

Of the 219 patients included in the study, 164 (74.9%) were women, 194 (88.6%) were between 18 and 59 years of age (mean [SD] age, 43.2 [12.9] years), 206 (94.1%) had more than 9 years of education, and 115 (52.5%) had a monthly income of up to US $192.00. In the study group, 139 patients (63.5%) had some degree of olfactory dysfunction, whereas 80 patients (36.5%) had normosmia. Patients with olfactory dysfunction had a significantly longer duration of long COVID symptoms than those in the normosmia group (mean [SD], 242.7 [101.9] vs 221.0 [97.5] days; P = .01). Among patients with anosmia, there was a significant association between olfactory dysfunction and daily activities, especially in terms of impairment in hazard detection (21 of 31 patients [67.7%]), personal hygiene (21 of 31 patients [67.7%]), and food intake (21 of 31 patients [67.7%]). Univariable logistic regression analyses found that ageusia symptoms were associated with the occurrence of olfactory dysfunction (odds ratio [OR], 11.14 [95% CI, 4.76-26.07]; P < .001), whereas headache (OR, 0.41 [95% CI, 0.22-0.76]; P < .001) and sleep disorders (OR, 0.48 [95% CI, 0.26-0.92]; P = .02) showed an inverse association with the occurrence of olfactory dysfunction.

CONCLUSIONS AND RELEVANCE

Olfactory dysfunction is one of the most important long-term neurologic symptoms of COVID-19, with the highest prevalence seen among women, adults, and outpatients. Patients with olfactory dysfunction may experience persistent severe hyposmia or anosmia more than 1 year from the onset of symptoms, suggesting the possibility of the condition becoming a permanent sequela.

Long‐term prevalence of taste and olfactory dysfunction in COVID‐19 patients: A cross‐sectional study

Objectives

The objectives of the study were to investigate the long‐term prevalence of taste disorder (TD) and olfactory disorder (OD) and associated risk factors in the non‐hospitalized southeastern Brazil population of COVID‐19 patients.

Methods

This cross‐sectional open survey evaluated possible long‐term OD and TD in non‐hospitalized patients who had been diagnosed with COVID‐19 for more than 30 days, through an online self‐report questionnaire. Demographic data, comorbidities, symptoms, and the intensity of OD and TD at the time of diagnosis and at the time of completing the questionnaire were evaluated.

Results

Three hundred five responses were included. The reported prevalence of OD and TD was 72.9% and 67.4%, respectively, in the moment of diagnosis; after a mean follow‐up period of 179 days, 45% and 50% still had some degree of the symptoms. There was a positive correlation between age and the high prevalence of OD (p = 0.02). However, there was no correlation between age and TD (p = 0.961) and weight in relation to OD/TD (p = 0.500 and p = 0.636, respectively).

Conclusion

This study observed a high long‐term prevalence of OD and TD associated with COVID‐19, with a low recovery rate during the study period. There was a positive association between older participants and the prevalence of OD.

Gustatory and Saliva Secretory Dysfunctions in COVID-19 Patients with Zinc Deficiency

Given the ever-progressing studies on coronavirus disease 2019 (COVID-19), it is critical to update our knowledge about COVID-19 symptomatology and pathophysiology. In the present narrative review, oral symptoms were overviewed using the latest data and their pathogenesis was hypothetically speculated. PubMed, LitCovid, ProQuest, and Google Scholar were searched for relevant studies from 1 April 2021 with a cutoff date of 31 January 2022. The literature search indicated that gustatory dysfunction and saliva secretory dysfunction are prevalent in COVID-19 patients and both dysfunctions persist after recovery from the disease, suggesting the pathogenic mechanism common to these cooccurring symptoms. COVID-19 patients are characterized by hypozincemia, in which zinc is possibly redistributed from blood to the liver at the expense of zinc in other tissues. If COVID-19 induces intracellular zinc deficiency, the activity of zinc-metalloenzyme carbonic anhydrase localized in taste buds and salivary glands may be influenced to adversely affect gustatory and saliva secretory functions. Zinc-binding metallothioneins and zinc transporters, which cooperatively control cellular zinc homeostasis, are expressed in oral tissues participating in taste and saliva secretion. Their expression dysregulation associated with COVID-19-induced zinc deficiency may have some effect on oral functions. Zinc supplementation is expected to improve oral symptoms in COVID-19 patients.