Background: Smell and taste dysfunctions are common and have been reported as an early indicator of COVID-19. The prevalence of smell and taste dysfunctions among children with COVID-19 varies greatly across studies, which remains to be summarized quantitatively. This review aimed at examining the pooled prevalence of smell or taste dysfunctions among children with COVID-19, summarizing possible causes of the inconsistencies in the current estimates. Methods: Systematic searches of databases were conducted for literature published until 12 January 2021. Statistical analyses were performed using R software, the pooled prevalence was combined using random effects model. The Loney criteria were used for quality assessment. Results: A total of 18 eligible studies were included. The results showed that the pooled prevalence of smell dysfunction among children with COVID-19 was 15.97% (95% CI: 8.18-23.77%), the pooled prevalence of taste dysfunction among children with COVID-19 was 9.20% (95% CI: 4.25-14.16%), the pooled prevalence of smell or taste dysfunction among children with COVID-19 was 15.50% (95% CI: 10.30-20.70%) and the pooled prevalence of smell and taste dysfunction among children with COVID-19 was 20.21% (95% CI: 14.14-26.28%). Higher smell or taste dysfunction rates were associated with being female, younger age, smaller sample size, patients in Asia, and with comorbidities. Conclusions: Evidence suggests that smell or taste dysfunctions were common among children with COVID-19. Further research is needed to identify effective strategies for preventing and treating smell and taste dysfunctions among children with COVID-19.

Taste dysfunction has been associated with aging and is therefore thought to be less common in children. However, children can face medical conditions influencing their taste function. Measuring and understanding taste dysfunction in children may foster the development of treatments/interventions mitigating the detrimental effects of taste dysfunction on children\'s appetite and quality of life. But measuring loss of taste function requires adequate tools. This review was conducted to 1) provide an overview of etiologies (i.e., disease and iatrogenic) associated with taste dysfunction in a pediatric population; 2) to investigate which tools (psychophysical tests and questionnaires) are available to assess taste function in children; and 3) to identify what tools can be and are actually used in clinical practice. It is concluded that only a minority of available tools to assess taste function in children are readily suitable for a pediatric clinical setting. Considering the profound impact of taste dysfunction in the pediatric setting, developing, and implementing a standard taste test that is sensitive, simple, and practical to use with children is pertinent.

Taste sensation is vital for a healthy body as it influences our food intake, acts as a defense mechanism and elicits pleasure. Majority of the head and neck cancer (HNC) patients undergoing radiotherapy suffer from altered taste function and often complain of inability to taste their food, reduced food intake, and weakness. However, there are not many studies conducted to assess this commonly reported side effect. Furthermore, clinical research on radiotherapy-induced taste alterations has proven to be difficult, considering a lack of reliable and validated study tools for assessing objective and subjective outcomes. Developing standardized tools for assessment of taste function and conducting prospective studies in larger population of HNC is the need of the hour. Taste sensation being critically important for sustenance, we need to focus on ways to preserve it. The physical properties of proton particle enable localization of the radiation dose precisely to the tumor and minimizing the exposure of the adjacent healthy tissues. By using Intensity-Modulated Proton Therapy in HNC patients, we anticipate preserving the taste sensation by reducing the dose of radiation to the taste buds.

Primary burning mouth syndrome (BMS) is a chronic oral condition characterized by burning pain often accompanied with taste dysfunction and xerostomia. The most compelling evidence concerning BMS pathophysiology comes from studies on the somatosensory system using neurophysiologic or psychophysical methods such as blink reflex, thermal quantitative sensory testing, as well as functional brain imaging. They have provided convincing evidence for neuropathic involvement at several levels of the somatosensory system in BMS pain pathophysiology. The number of taste function studies trying to substantiate the subjective taste disturbances or studies on salivary factors in BMS is much more limited, and most of them suffer from definitional and methodological problems. This review aims to critically evaluate the existing literature on the pathophysiology of BMS, paying special attention to the correctness of case selection and the methodology used in published studies, and to summarize the current state of knowledge. Based on the recognition of several gaps in the current understanding of the pathophysiology of BMS especially as regards taste and pain system interactions, the review ends with future scenarios for research in this area.