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Neurolymphomatosis (NL) is a rare complication of non-Hodgkin's lymphoma, characterized by the infiltration of lymphoma cells into the peripheral nerves. A 54-year-old woman initially presented with right facial palsy without any other significant symptoms and was diagnosed with Bell's palsy. Despite initial improvement, her condition recurred, prompting further evaluation. Magnetic resonance imaging (MRI) revealed contrast enhancement from the tympanic segment to the surface of the masseter muscle along the right facial nerve and an adjacent mass lesion. Biopsy of the mass revealed a diagnosis of T-cell/histiocyte-rich large B-cell lymphoma. Chemotherapy resulted in complete resolution of facial palsy. Follow-up MRI confirmed the absence of contrast enhancement along the facial nerve. Facial palsy was considered to be caused by NL. This case was classified as that of primary NL because the facial palsy was the first manifestation of a hematologic malignancy. Recurrent facial palsy, which is atypical in Bell's palsy, led to further evaluation with MRI, which finally resulted in the diagnosis of malignant lymphoma. In cases of recurrent facial palsy, clinicians should consider various diagnoses, including that of NL, and advocate early imaging tests and biopsy, if possible, for accurate diagnosis and improved outcomes., Competing Interests: Declaration of competing interest None., (Copyright © 2024. Published by Elsevier B.V.)

Background: Prior studies have reported a potential relationship between depressive disorder (DD), immune function, and inflammatory response. Some studies have also confirmed the correlation between immune and inflammatory responses and Bell's palsy. Considering that the pathophysiology of these two diseases has several similarities, this study investigates if DD raises the risk of developing Bell's palsy., Methods: This nationwide propensity score-weighting cohort study utilized Taiwan National Health Insurance data. 44,198 patients with DD were identified as the DD cohort and 1,433,650 adult subjects without DD were identified as the comparison cohort. The inverse probability of treatment weighting (IPTW) strategy was used to balance the differences of covariates between two groups. The 5-year incidence of Bell's palsy was evaluated using the Cox proportional-hazard model, presenting results in terms of hazard ratios (HRs) and 95% confidence intervals (CIs)., Results: The average age of DD patients was 48.3 ± 17.3 years, and 61.86% were female. After propensity score-weighting strategy, no significant demographic differences emerged between the DD and comparison cohort. The Cox proportional hazards model revealed a statistically significant adjusted IPTW-HR of 1.315 (95% CI: 1.168-1.481) for Bell's palsy in DD patients compared to comparison subjects. Further independent factors for Bell's palsy in this model were age (IPTW-HR: 1.012, 95% CI: 1.010-1.013, p < 0.0001), sex (IPTW-HR: 0.909, 95% CI: 0.869-0.952, p < 0.0001), hypertension (IPTW-HR: 1.268, 95% CI: 1.186-1.355, p < 0.0001), hyperlipidemia (IPTW-HR: 1.084, 95% CI: 1.001-1.173, p = 0.047), and diabetes (IPTW-HR: 1.513, 95% CI: 1.398-1.637, p < 0.0001) CONCLUSION: This Study confirmed that individuals with DD face an elevated risk of developing Bell's palsy. These findings hold significant implications for both clinicians and researchers, shedding light on the potential interplay between mental health and the risk of certain physical health outcomes., (© 2024. The Author(s).)

Lyme neuroborreliosis is a rare zoonosis which can be difficult to diagnose, in particular in low endemic areas. We here report the case of a 35-year-old man presenting with disabling back pain preceded by facial monoplegia, which was wrongly treated as Bell's palsy (paralysis a frigore) and then as post-traumatic lumbosciatica. The onset of facial diplegia allowed for a definitive diagnosis. The patient was treated with ceftriaxone and symptoms gradually improved., Competing Interests: Les auteurs ne déclarent aucun conflit d´intérêts., (Copyright: Sophie Collignon et al.)

Introduction: Cholesteatoma is a rare disease characterized by the accumulation of keratinized squamous epithelial cells in the middle ear or mastoid cavity. Vertigo and facial palsy, which are rare complications, may indicate erosion into the semicircular canals or the fallopian canal., Patient Concerns: A 40-year-old woman presented to our clinic with progressive right-sided hearing loss over 5 years (primary concern). Approximately 10 years ago, the patient had developed acute right-sided facial weakness with no additional symptoms. A neurologist at another hospital had diagnosed her condition as Bell's palsy and treated it accordingly., Diagnosis: Adult-onset congenital cholesteatoma in the hypotympanum., Intervention: Combined endoscopic and microscopic removal of the cholesteatoma., Outcomes: Physical examination revealed slight improvement in right-sided peripheral facial palsy., Lesson: Routine eardrum examination is recommended for patients presenting with isolated peripheral facial palsy. If necessary, a patient should be referred to an otologist for further evaluation and treatment., Competing Interests: The authors have no funding and conflicts of interest to disclose., (Copyright © 2024 the Author(s). Published by Wolters Kluwer Health, Inc.)

Background: Coronavirus disease 2019 (COVID-19) has been linked to Bell's palsy and facial paralysis. Studies have also shown increased risk of Bell's palsy in unvaccinated COVID-19 patients. Objective: To compare the relationship between Bell's palsy and COVID-19 infection and vaccination. Design: This is a retrospective longitudinal study. Methods: The COVID-19 research network was used to identify patients with facial palsy presenting to 70 health care organizations in the United States. The incidence of Bell's palsy was measured within an 8-week window after COVID-19 test or vaccination event in identified patients. Results: Incidence of facial palsy diagnosis (0.99%) was higher than the background rate within 2 months of COVID-19 infection. When compared with their negative counterparts, patients with COVID-19 infection had significantly higher risk of Bell's palsy (risk ratio [RR] = 1.77, p  < 0.01) and facial weakness (RR = 2.28, p  < 0.01). Risk ratio was also amplified when evaluating Bell's palsy (RR = 12.57, p  < 0.01) and facial palsy (RR = 44.43; p  < 0.01) in COVID-19-infected patients against patients who received COVID-19 vaccination. Conclusion: In our patient population, there is a higher risk of developing facial palsy within 2 months of COVID-19 infection versus vaccination. Vaccinated patients are not at higher risk of developing facial palsy.

Objectives: Despite some evidence of an increased risk of neurologic symptoms following viral vector COVID-19 vaccine administration, it is unclear whether SARS-CoV-2 infection is associated with Bell's palsy (BP), especially over a long enough follow-up period., Methods: The study population of this nationwide population-based study was derived from the South Korean population, including 11 593 365 and 36 565 099 participants with and without COVID-19, respectively. The Fine and Gray's regression model was utilized to calculate the adjusted subdistribution hazard ratio (aSHR), considering death as a competing risk, to assess the association between SARS-CoV-2 infection and the risk of BP. All participants were followed up from 1 December 2021, until the incident BP, SARS-CoV-2 infection, death, or 31 March 2022. Subgroup analyses were conducted based on participants' vaccination status (completion of the primary series vs. unvaccinated)., Results: COVID-19 was associated with an increased risk of BP in all participants (aSHR, 1.24; CI, 1.19-1.29). However, the size of the COVID-19-related BP risk was significantly lower among those who completed the primary series of the COVID-19 vaccine (aSHR, 1.20; 95% CI, 1.15-1.25) compared to those who were unvaccinated (aSHR, 1.84; 95% CI, 1.59-2.12; p for interaction: <0.001). The severity of COVID-19 exhibited a gradual escalation in BP risk for both vaccinated and unvaccinated individuals., Discussion: While both unvaccinated individuals and those who completed the primary series of the COVID-19 vaccine may be at an increased risk of developing BP due to COVID-19, the risk appears to be lower among those who completed the vaccination., (Copyright © 2023 European Society of Clinical Microbiology and Infectious Diseases. Published by Elsevier Ltd. All rights reserved.)

Objective: Epidemiological and clinical studies have shown that sharp changes in the ambient temperature are associated with the occurrence and development of Bell's palsy. However, the specific pathogenesis of peripheral facial paralysis remains nebulous. This study investigated the effect of cold stress on transient receptor potential cation channel subfamily V member 2 (TRPV2) secretion by Schwann cells and its role in Bell's palsy., Materials and Methods: Schwann cell morphology was observed using transmission electron microscopy (TEM). Cell proliferation, apoptosis and cell cycle were analysed using CCK8 and flow cytometry. ELISA, Reverse transcription-quantitative PCR, western blotting and immunocytochemical fluorescence staining were used to detect the effects of cold stress on TRPV2, neural cell adhesion molecule (NCAM) and nerve growth factor (NGF) expression in Schwann cells., Results: Cold stress resulted in a widening of the intercellular space, and the particles on the membrane showed different degrees of loss. Cold stress may cause Schwann cells to enter a cold dormant state. ELISA, RT-qPCR, western blotting and immunocytochemical fluorescences staining indicated that cold stress inhibited the expression of TRPV2, NCAM, and NGF., Conclusions: Drastic temperature difference between cold and heat can downregulate TRPV2 and the secretome of Schwann cells. The imbalance of Schwann cell homeostasis under such stress may contribute to nerve signalling dysfunction leading to the development of facial paralysis., Competing Interests: Declaration of Competing Interest The authors declare that there is no conflict of interest regarding this manuscript., (Copyright © 2023 The Authors. Published by Elsevier Masson SAS.. All rights reserved.)

Background: Although an association between COVID-19 vaccination and Bell's palsy (BP) has been reported, a clear causal relationship has not been elucidated. We investigated the risk and clinical characteristics of BP after COVID-19 vaccination., Methods: This retrospective chart review evaluated the association between COVID-19 vaccination and BP by comparing the number of patients diagnosed with BP during the pre-COVID-19 vaccination period (March 2018-February 2021) and the COVID-19 mass vaccination period (March 2021-February 2022). We then compared vaccine-related (time between vaccination and BP onset < 42 days) and -unrelated (time interval ≥ 42 days or non-vaccination) clinical characteristics in newly diagnosed patients with BP., Results: BP occurred more during the COVID-19 vaccination period than in the previous three pre-vaccination years. Thirteen patients developed BP within 42 days of vaccination. All patients, except one, developed BP after mRNA-based vaccination, with most cases (9/13, 69.2%) occurring after the second or third dose. Thirteen patients with vaccine-related BP were younger (age 43.92 ± 13.14 vs. 54.32 ± 16.01 years; p = 0.033) and more frequently experienced taste changes (58.8% vs. 10.9%; p = 0.002) than 52 patients with vaccine-unrelated BP. Patients with vaccine-related BP had a greater likelihood of good and faster (p = 0.042) facial nerve function recovery than those with vaccine-unrelated BP (100% vs. 78%)., Conclusion: COVID-19 vaccines, especially mRNA-based vaccines, may be associated with BP cases with distinctive clinical characteristics, which occur more frequently in young individuals, are frequently accompanied by taste changes, and have fast and good recovery., (© 2023. The Author(s) under exclusive licence to Belgian Neurological Society.)

The etiology of Bell's palsy (BP) is currently unknown, and the findings from previous studies examining the association between seasonal or meteorological factors and BP have been inconsistent. This research aims to clarify this relationship by analyzing a larger dataset and employing appropriate statistical methods. Data from 5387 patients with BP treated at Zhejiang Provincial Hospital of Traditional Chinese Medicine in Hangzhou, Zhejiang Province, from May 1, 2018, to June 30, 2023, was gathered. We assessed the temporal distribution of meteorological factors and the incidence of BP across seasons and months. A distributed lag non-linear model was used to further investigate the lagged and overall effects of temperature and air pressure on the onset of BP. The temporal distribution of BP incidence revealed the highest average number of cases occurring in December and the lowest in June. A correlation existed between BP episodes and temperature or air pressure. The model revealed a higher relative risk during periods of low temperature and high air pressure, characterized by a time lag effect. This correlation was notably more pronounced in female patients and individuals in the young and middle-aged groups. Our findings suggest that exposure to low temperatures and high air pressure constitute risk factors for BP development., (© 2023. The Author(s).)

Background: While the etiology of Bell's palsy (BP) is largely unknown, current evidence shows it may occur secondary to the immune response following a viral infection. Recently, BP has been reported as a clinical manifestation of coronavirus disease (COVID-19)., Objectives: To investigate an association between COVID-19 infection and BP. Additionally, to evaluate the need for COVID-19 testing in patients who present with BP., Methods: Hospital records of patients who presented to a single tertiary care center with BP in 2020 and 2021 were reviewed for presenting symptoms, demographics, COVID-19 infection and vaccination status., Results: There was no statistically significant difference between patients with BP who had a positive or negative COVID test in terms of sex, BMI, age, race, smoking history or alcohol use. All 7 patients with BP and a positive COVID test were unvaccinated. Of the total cohort of 94 patients, 82 % were unvaccinated at the time of the study. None of the 17 patients who were vaccinated had a positive COVID test. A history of BP showed no statistical significance (10.3 % vs 14.3 %, p-value 0.73)., Conclusion: We discovered a limited cohort of patients who underwent COVID-19 testing at the time of presentation for BP. Though there have been recent studies suggesting a COVID-19 and BP, we were unable to clearly identify a relationship between COVID-19 and BP. Interestingly, all patients with facial paralysis and COVID-19 were unvaccinated. To further study this relationship, we recommend consideration of a COVID-19 test for any patient that presents with facial paralysis., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Objective: This systematic review and meta-analysis aimed to identify studies reporting the incidence of Bell's Palsy after vaccination against coronavirus disease 2019 (Covid-19) and assess whether this incidence is greater than among the general population., Data Sources: PubMed, Embase, CINAHL, and Web of Science., Review Methods: A systematic review was performed in accordance with Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines. Databases were searched from inception to May 9, 2022, for studies reporting the incidence of Bell's Palsy among individuals vaccinated against Covid-19 and control populations. Meta-analyses of odds ratios (ORs) were performed to compare the incidence of Bell's Palsy in these groups., Results: We identified 7 studies reporting the incidence of Bell's Palsy after vaccination and among the general population, including 20,234,931 total vaccinated patients. The length of postvaccination follow-up ranged from 7 to 43 days in these studies. The incidence of Bell's Palsy was not significantly greater among vaccinated individuals (OR: 1.06; 95% confidence interval [CI]: 0.65-1.71; p = .82). Stratifying by dose, the incidence of Bell's Palsy was not significantly greater after receiving either the first dose (OR: 0.84; 95% CI: 0.47-1.49; p = .54) or second dose (OR: 1.02; 95% CI: 0.58-1.79; p = .96)., Conclusion: Among the available evidence, the incidence of Bell's Palsy after vaccination against Covid-19 is comparable to that of the general unvaccinated population. Patient counseling should provide reassurance that there is no known association between Bell's Palsy and Covid-19 vaccination., (© 2023 American Academy of Otolaryngology-Head and Neck Surgery Foundation.)

Competing Interests: Declaration of Conflicting InterestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

&lt;br&gt;&lt;b&gt;Introduction:&lt;/b&gt; Bell's palsy is still the diagnosis of exclusion. In most patients it does not progress, it is unilateral, and selflimiting. Additionally, the majority of patients recover spontaneously within 3 weeks. It is well known that all patients with irreversible facial nerve paresis (FNP) need further examinations to exclude the organic, infectious, metabolic, and autoimmunological causes of the palsy. The goal of the study was to assess the frequency of malignancies hidden under the diagnosis of "Bell's palsy".&lt;/br&gt; &lt;br&gt;&lt;b&gt;Aim:&lt;/b&gt; We aimed to create a diagnostic algorithm to avoid failures concerning patients whose only symptom of parotid gland cancer was irreversible FNP.&lt;/br&gt; &lt;br&gt;&lt;b&gt;Material and methods:&lt;/b&gt; We analyzed 253 consecutive patients with FNP treated in our department in the last 5 years. The subject of the study was "Bell's palsy" cases. All patients with irreversible FNP were reassessed in 6-12 months. We underlined all shortcomings in the diagnostics of those in whom malignancies were found in MRI of the neck and presented the proposal for a diagnostic algorithm to avoid missing such an entity.&lt;/br&gt; &lt;br&gt;&lt;b&gt;Results:&lt;/b&gt; Bell's palsy was observed in 157/253 patients (62.06%), in 36/157 (22.92%) it remained permanent. In 4/36 patients (11.11%) with irreversible FNP, which constituted 2.54% of all "Bell's palsy" cases, parotid gland deep lobe mass was found in MRI. In one patient, infiltration of the skull base was diagnosed. Adenoid cystic carcinoma was confirmed in final histopathology in all cases.&lt;/br&gt; &lt;br&gt;&lt;b&gt;Conclusions:&lt;/b&gt; Our experience has shown that irreversible FNP can be a revelator of the malignant tumor located in the deep lobe of the parotid gland. Contrast-enhanced MRI covering intra- and extracranial segments of the facial nerve should be ordered in all cases of FNP without recovery after 4 months. Repeated imaging should be considered in undiagnosed cases. The main point of our study is to underline that the assessment of the deep lobe of the parotid gland with MRI should be included in the standard diagnostic protocol in all irreversible "Bell's palsy" cases.&lt;/br&gt.

Peripheral facial palsy is a common clinical symptom and is most often caused by Bell's palsy. The pathogenesis is largely unknown, but inflammation of the facial nerve, possibly after a viral infection, may play a role. Bell's palsy has a monophasic course with usually - but not always - a good recovery. Even though Bell's palsy exhibits clear clinical features, in clinical practice diagnosis and choice of treatment remain difficult and other causes of an isolated facial palsy may easily be overlooked.

Importance: Annual administration of the influenza vaccine (fluVc) is currently the most effective method of preventing the influenza virus in older adults. However, half of adults older than 65 years remain unvaccinated in Taiwan, possibly because of concern about adverse events, such as Bell palsy (BP). Currently, studies on the association between fluVc and risk of BP are inconsistent., Objective: To determine whether the incidence of BP increases following fluVc in older adults., Design, Setting, and Participants: A self-controlled case series study design was used. Days 1 through 7, days 8 through 14, days 15 through 30, and days 31 through 60 following fluVc were identified as risk intervals, and days 61 through 180 were considered the control interval. A total of 4367 vaccinated individuals aged 65 years or older who developed BP within 6 months following fluVc were enrolled. Population-based retrospective claims data were obtained between 2010 and 2017; data were analyzed from April 2022 through September 2022., Exposure: Government-funded seasonal fluVc., Main Outcomes and Measures: The outcome of interest was BP onset in risk intervals compared with control intervals. Three or more consecutive diagnoses of BP within 60 days following fluVc were used as the definition of a patient with BP. Poisson regression was used to analyze the incidence rate ratio (IRR) of risk intervals compared with control intervals., Results: In total, 13 261 521 patients who received the fluVc were extracted from the National Health Insurance Research Database in Taiwan from January 1, 2010, to December 31, 2017. Of those, 7 581 205 patients older than 65 years old met the inclusion criteria. The number of patients with BP diagnosed within 6 months following fluVc enrolled for risk analysis was 4367 (mean [SD] age, 74.19 [5.97] years; 2349 [53.79%] female patients). The incidence rate of BP among all observed fluVc older adults was 57.87 per 100 000 person-years. The IRRs for BP on days 1 through 7, days 8 through 14, and days 15 through 30 were 4.18 (95% CI, 3.82-4.59), 2.73 (95% CI, 2.45-3.05), and 1.67 (95% CI, 1.52-1.84), respectively. However, there was no increase during days 31 through 60 (IRR, 1.06; 95% CI, 0.97-1.16). The postvaccination risk of BP was consistent across all subgroups stratified by sex, age group, and baseline conditions., Conclusions and Relevance: The present self-controlled case series indicated that the risk of BP in individuals older than 65 years increased within the first month, especially within the first week, following fluVc. But overall, the adverse event rate of BP was low, and considering the morbidity and mortality of influenza infection, the benefits of fluVc still outweigh the risks.

Peripheral facial palsy is a common, often idiopathic and self-limiting mononeuropathy. However, secondary facial palsies require specific management: they are most often of infectious, vascular or dysimmune causes. The presence of red flags in the history, clinical examination or medical follow-up should alert clinicians. Because of the high incidence of Lyme disease in our region, this etiology deserves special attention. The management is based on general measures (eye protection, rehabilitation) and corticosteroid therapy; antivirals may provide additional benefit., Competing Interests: Les auteurs n’ont déclaré aucun conflit d’intérêt en relation avec cet article.

Although previous studies have suggested that meteorological factors are associated with Bell's palsy, articles on this topic are rare and the results are inconsistent. We aim to reveal the relationship between exposure to different meteorological factors and the onset of severe Bell's palsy (SBP) with daily data. A case-crossover study based on time-series data was applied, and the minimum risk value of each climatic factor was set as the reference value. We fitted a distributed lag non-linear model (DLNM) which applied quasi-Poisson regression to evaluate the exposure-response association and the lag-response association of meteorological factors on the occurrence of SBP. The mode value and per-decile interval value of each meteorological factor were all included in the analysis. Sensitivity analyses were conducted to test the robustness of results. A total of 863 SBP patients (474 males and 389 females) from 7 hospitals in the Shenzhen Futian District were selected from January 2009 to February 2020. The highest relations effect was tested in the cumulative exposure-response result shown as follows; mean temperature at the minimum value 15.3°C with RR of 10.370 (1.557-69.077) over lag 0 to 13; relative humidity at the 30th value 71% with RR of 8.041 (1.016-63.616) over lag 0 to 14; wind speed at the 90th value 31 (0.1 m/s) with RR of 1.286 (1.038-1.593) over lag 0; mean air pressure at the 30th value 1001.4 (pa) with RR of 9.052 (1.039-78.858) over lag 0 to 5; visibility at the 80th value 26.5 (km) with RR of 1.961 (1.005-1.423) over lag 0 to 2; average total cloud cover at the max value 100 (%) with RR 1.787 (1.014-3.148) over lag 0 to 2; sunshine duration at the 10th value 0.1 (h) with RR of 4.772 (1.018-22.361); daily evaporation shows no relationship in the cumulative result; daily average solar radiation at the minimum value 0 (W/m2) with RR of 5.588 (1.184-26.382). There is a relationship between wind speed and the onset of SBP, while mean air pressure, visibility, and average total cloud cover, especially sunshine duration and solar radiation which showed a strong effect, may be associated with severe clinical symptoms of SBP. Mean temperature and relative humidity may affect the course of SBP., Competing Interests: The authors have no conflicts of interest to disclose., (Copyright © 2023 the Author(s). Published by Wolters Kluwer Health, Inc.)

The facial nerve emerges out of skull through the stylomastoid foramen located between styloid process and mastoid process. Unilateral paralysis of facial nerve is known as Bell's palsy and is reported to be caused most frequently by herpes simplex virus. The herpes infection is comparatively common but Bell's palsy is not very common. So, other causes of Bell's palsy like variation in morphological forms of stylomastoid cannot be ruled. There is paucity of literature elucidating morphological shapes of this foramen and correlating these forms of foramen with Bell's palsy. Hence the study was carried out. The aim of this study is to expound varied forms of stylomastoid foramen and to bring out clinical implications. The study was conducted in the department of anatomy using undamaged 70 adult dry human skulls of unknown age and sex. The morphological shapes were observed, interpretated and compared with available literature and their clinical implications were brought out. Most common shapes observed were round and oval followed by square shapes. Round shaped foramina were observed in 40 skulls on right sides constituting 57.1% and in 36 skulls on left side constituting 51.4%. While oval shapes were found in 16 skulls on right side (22.6%) and in 12 skulls on left side (17.1%). Rare variants of the foramen include triangular, serrated and closely applied to styloid process. The rare morphological forms were mostly observed to be unilateral in occurrence. Unilateral Bell's palsy is common, so, the rare morphological forms might be responsible for Bell's palsy., Competing Interests: The author reports no conflicts of interest., (Copyright © 2023 by Mutaz B. Habal, MD.)

Purpose: During COVID-19 pandemic, the authorization of emergent usage of new vaccine has raised suspicions and doubts about potential adverse events related to vaccination. Among the reported adverse events related to ChAdOx1/nCoV-19 vaccine, facial paralysis did not have an incident rate higher than natural occurrence like mRNA vaccines. However, temporal association between vaccination and facial palsy have been documented in several studies. Here, we report a case of an otherwise healthy 23-year-old Taiwanese female who experienced prolonged headache since the second day postvaccination and developed facial palsy on the tenth day., Case Report: A 23-year-old Taiwanese female who was previously healthy experienced intermittent right side throbbing headache, general malaise, myalgia and fever. Headache, transient ear pain and right scalp numbness developed in the next few days but quickly resolved. On day ten after vaccination, signs of facial palsy on the right side of her face was noticed. The results of brain Magnetic Resonance Imaging (MRI) with contrast displayed no abnormality. Facial stimulation and blink reflex tests were compatible with right facial neuropathy., Conclusion: Reactivation of latent herpes virus has been suggested as one of the possible mechanisms underlying the phenomenon, but the causal pathophysiology related to the symptom needs further validation. Moreover, in the event of facial palsy post-vaccination, alternative diagnoses such as Guillain-Barre syndrome (GBS), Ramsey-Hunt syndrome, Lyme disease, trauma, central nervous system infection (CNS) infection, or stroke should also be considered.

Purpose: We hypothesize that delayed facial paralysis following dental procedures is also associated with viral reactivation. In this study, the brain magnetic resonance imaging (MRI) findings of patients were analyzed to identify the pathogenesis of facial nerve palsy after dental treatment., Materials and Methods: We retrospectively reviewed the medical records of patients with unilateral facial nerve palsy and identified those diagnosed with delayed facial nerve palsy within 30 days of dental treatment. We assessed the clinical characteristics, electrodiagnostic findings, and imaging findings of these patients and looked for MRI findings that support a viral hypothesis for facial palsy., Results: Among 924 patients with facial palsy, 11 (1.2%) had delayed facial paralysis following dental procedures. Patients developed facial palsy at an average of 3.2 days (1-11 days) after undergoing a dental procedure. The internal auditory canal MRI revealed abnormal enhancement of affected facial nerve in nine patients. The intensity and pattern of the enhancement were similar to those of Bell's palsy., Conclusions: Facial palsy can develop within the days following dental procedures, and the MRI results suggest that delayed facial palsy after dental treatment is related to viral reactivation-like Bell's palsy., (© 2022. The Author(s) under exclusive licence to Belgian Neurological Society.)

Peripheral facial nerve palsy (PFP) is a rare occurrence after dental extraction. Early onset PFP after the procedure can be caused by trauma and/or local anesthesia, whereas delayed onset PFP has more speculative etiologies. The latter has a certain affiliation to Bell's palsy and is therefore primarily treated with corticosteroids, and long-term follow-up is often warranted. This article reports a unique case of a 30-year-old woman developing a delayed onset right-sided PFP after local intraoral anesthetic injection for molar extraction. Facial nerve injury was identified with signs of denervation and neuritis and the patient was treated with nonsteroidal anti-inflammatory drug, corticosteroids, vitamin B supplements, and mime therapy. After 9 months, the patient showed an improvement of the facial muscle activity and went from a grade IV to a grade III on the House-Brackmann grading scale.

The association between vaccines and peripheral facial palsy (PFP), an issue that has been the subject of debate for many years, has been raised again following results of clinical trials assessing mRNA based COVID-19 vaccines. To review the available literature on this topic, PubMed was searched from inception until February 25, 2022. Inclusion criteria were case reports with documented rechallenge and comparative epidemiological studies. Cases of COVID-19 vaccine-induced PFP with available data on vaccine rechallenge were also identified from Vigibase until December 31, 2021. Of the 347 articles retrieved, 32 comparative epidemiological studies, 1 meta-analysis and 4 case reports met our criteria, of which 13 involved COVID-19 vaccines. Eight studies found an association between at least one vaccine and the occurrence of PFP, whereas 24 did not. Positive studies involved seasonal or pandemic H1N1 influenza vaccines administered parenterally (4 studies) or intranasally (1 study with a toxin-adjuvanted vaccine), BNT162b2, a mRNA COVID-19 vaccine (1 disproportionality analysis and 1 observed-to-expected analysis) and an inactivated virus COVID-19 vaccine (CoronaVac®) (1 study combining a case-control and an observed-to-expected approach). Strong evidence was found only for the intranasal influenza vaccine while other positive studies detected only a marginal association between PFP and vaccination. Of the four case reports with documented rechallenge, only two were positive and involved an influenza vaccine and tozinameran in one case each. In Vigibase, rechallenge was documented in 49 reports with 29 (59.2%) cases being negative and 20 (40.8%) positive. The available data did not confirm an excess risk of PFP after vaccination in most studies. Moreover, of the eight epidemiological studies suggesting a possible excess risk of PFP after any vaccine, three were disproportionality analyses and two observed-to excepted analyses, suggesting great caution should be taken when interpreting these results., (Copyright © 2022 Société française de pharmacologie et de thérapeutique. Published by Elsevier Masson SAS. All rights reserved.)

BACKGROUND The present study aimed to investigate the relationship between Bell's palsy (BP) and cerebral white matter lesions (CWMLs) on brain gadolinium-enhanced magnetic resonance imaging (MRI). MATERIAL AND METHODS The study included 51 patients who were diagnosed with BP and a control group of 40 individuals who underwent brain MRI for investigation of headache etiology. The brain MRIs of the patients were reviewed with respect to CWMLs. CWMLs were compared between the 2 groups, and within the BP group, the correlation between CWML and House-Brackmann (HB) facial nerve palsy grade was investigated as well. RESULTS There were significantly more CWMLs in the BP group than in the control group (P=0.003). There was a statistically significant difference between the HB subgroups in terms of absence/presence of CWMLs (P=0.040). Within the BP patient group, there were significantly more CWMLs in the HB grade 5 and 6 groups compared with the HB grade 2 group (P=0.025 and P=0.042, respectively). Overall, the CWML scores correlated positively with HB grade. When absence/presence of CWMLs was compared between the BP and control groups in only patients aged <50 years, there was a statistically significant difference between the groups (P=0.008). No statistically significant difference in absence/presence of CWMLs, however, was found between the BP and control groups when only patients age ≥50 years were considered (P=0.809). CONCLUSIONS We showed that as the severity of Bell's palsy increased, CWMLs increased and there was an association between CWMLs and BP. Microvascular ischemic pathologies may be among the most important factors in the etiopathogenesis of BP.

Background: Peripheral facial paralysis (PFP) results in functional disorder and social dysfunction, when it is under a severe condition at onset, long-term poor outcomes do occur. Different acupuncture methods have been reported to be potentially effective for shortening the disease course and reducing the occurrence of sequelae when they are applied at an early stage. Neuro edema is a common pathological feature in the acute phase, and many clinical studies have suggested its effect of reducing facial nerve edema. It is of value to estimate the effectiveness and safety of acupuncture treatment at the onset, and to assess the most suitable acupuncture method for the acute period., Methods and Analysis: All the RCTs and quasi-RCTs on acupuncture therapy for patients who is during acute stage of PFP will be included. The recovery rate of facial function, the time it takes to restore facial function and the odds of sequelae occurring will be the key parts we focus on. Psychological well-being and quality of life will also be evaluated. Literature searching will be conducted until December 31th, 2022 from eight databases systematically. Two reviewers will screen the literature and extract the data independently. RevMan software will be used for data analysis, and the version 2 of the Cochrane risk-of-bias tool (RoB 2) will be used to assess the certainty of evidence. Forest plots and summary findings will be generated. If data permits, a meta-analysis will be conducted., Ethics and Dissemination: Since this study will not involve clinical treatment of patients, ethics approval is not required. The result of this study will be submitted to a peer-reviewed journal for publication and as a proposal for clinical practice and further study on acupuncture treatment at the early stage of PFP., Discussion: This review will summarize the evidence on the different type of acupuncture therapy for acute Bell's palsy and Ramsay-Hunt syndrome. We anticipate that it would be safe and effective when applied to the acute phase of PFP, and some specific suitable acupuncture methods would be found resulting from this review., Systematic Review Registration: International Prospective Register for Systematic Reviews (PROSPERO) number CRD42020205127., (© 2023. The Author(s).)

Background: Observable symptoms of Bell's palsy following vaccinations arouse concern over the safety profiles of novel coronavirus disease 2019 (COVID-19) vaccines. However, there are only inconclusive findings on Bell's palsy following messenger (mRNA) COVID-19 vaccination. This study aims to update the previous analyses on the risk of Bell's palsy following mRNA (BNT162b2) COVID-19 vaccination., Methods: This study included cases aged ≥16 years with a new diagnosis of Bell's palsy within 28 days after BNT162b2 vaccinations from the population-based electronic health records in Hong Kong. Nested case-control and self-controlled case series (SCCS) analyses were used, where the association between Bell's palsy and BNT162b2 was evaluated using conditional logistic and Poisson regression, respectively., Results: Totally 54 individuals were newly diagnosed with Bell's palsy after BNT162b2 vaccinations. The incidence of Bell's palsy was 1.58 (95% confidence interval [CI], 1.19-2.07) per 100 000 doses administered. The nested case-control analysis showed significant association between BNT162b2 vaccinations and Bell's palsy (adjusted odds ratio [aOR], 1.543; 95% CI, 1.123-2.121), with up to 1.112 excess events per 100 000 people who received 2 doses of BNT162b2. An increased risk of Bell's palsy was observed during the first 14 days after the second dose of BNT162b2 in both nested case-control (aOR, 2.325; 95% CI, 1.414-3.821) and SCCS analysis (adjusted incidence rate ratio, 2.44; 95% CI, 1.32-4.50)., Conclusions: There was an overall increased risk of Bell's palsy following BNT162b2 vaccination, particularly within the first 14 days after the second dose, but the absolute risk was very low., Competing Interests: Potential conflicts of interest. E. Y. F. W. has received research grants from the Food and Health Bureau of the Government of the HKSAR and the Hong Kong Research Grants Council (RGC), outside the submitted work. C. S. L. C. has received grants from the Food and Health Bureau of the Hong Kong Government, Hong Kong RGC, Hong Kong Innovation and Technology Commission, Pfizer, IQVIA, and Amgen (all paid to institution) and a personal fee from Primevigilance Ltd, outside the submitted work. E. W. Y. C. reports honorarium from the Hospital Authority and grants from the Hong Kong RGC, Research Fund Secretariat of the Food and Health Bureau, National Natural Science Fund of China, Wellcome Trust, Bayer, Bristol-Myers Squibb, Pfizer, Janssen, Amgen, Takeda, and the Narcotics Division of the Security Bureau of HKSAR, outside the submitted work (no payments from Wellcome Trust, all other payments to institution). F. T. T. L. has been supported by the RGC Postdoctoral Fellowship under the Hong Kong RGC (paid to institution Chinese University of Hong Kong) and has received research grants from the Food and Health Bureau of the Government of the HKSAR, outside the submitted work. X. L. has received research grants from the Food and Health Bureau of the Government of the HKSAR, RGC Early Career Scheme, and RGC Research Matching Grant Scheme; research and educational grants from Janssen and Pfizer (all paid to institution); internal funding from the University of Hong Kong; a consultancy fee from Merck Sharp & Dohme, paid to author and unrelated to this work; and payment to author for lectures, presentations, speakers bureaus, manuscript writing, and educational events from Pfizer. K. K. L. received grants from the Research Fund Secretariat of the Food and Health Bureau, Innovation and Technology Bureau, RGC, Amgen, Boehringer Ingelheim, Eisai, and Pfizer and consultation fees from Amgen, Boehringer Ingelheim, Daiichi Sankyo, and Sanofi, all outside the submitted work. B. J. C. received consulting fees paid to author from AstraZeneca, Fosun Pharma, GSK, Moderna, Pfizer, Roche, and Sanofi Pasteur. I. F. N. H. received speaker fees from MSD for the COVID-19 Regional Expert Input Forum 2021 and Herpes Zoster Lecture 2021. I. C. K. W. reports research funding outside the submitted work from Amgen, Bristol-Myers Squibb, Pfizer, Janssen, Bayer, GSK, Novartis, the Hong Kong RGC, the Hong Kong Health and Medical Research Fund, the National Institute for Health Research in England, European Commission, National Health and Medical Research Council in Australia, Narcotics Division of the Security Bureau of HKSAR, and the Wellcome Trust; received speaker fees paid to author from Janssen, Medice, and Amgen; and is an independent nonexecutive director of Jacobson Medical in Hong Kong. C. K. H. W. has received grants or contracts paid to institution from Health and Medical Research Fund, Food and Health Bureau, HKSAR Government, General Research Fund, RGC, HKSAR Government, and Euroqol Research Foundation. All remaining authors: No reported conflicts of interest. All authors have submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Conflicts that the editors consider relevant to the content of the manuscript have been disclosed., (© The Author(s) 2022. Published by Oxford University Press on behalf of Infectious Diseases Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Sudden onset, bilateral facial paralysis is a rare clinical entity, representing less than 2% of all diagnoses of facial nerve paralysis. The differential for these patients is necessarily broad and includes numerous etiologies. Metastatic breast carcinoma to the bilateral parotid glands is also exceedingly rare with only 2 reported case reports noted in the literature, neither of which demonstrated facial nerve paralysis. Here, we report the only known occurrence of a patient presenting with synchronous bilateral facial nerve paralysis secondary to metastatic breast carcinoma to the bilateral parotid glands. This exceedingly rare clinical presentation was further confounded by the presence of autoimmune antibodies, highlighting the importance of the diagnostic process and maintaining broad clinical suspicion.

Facial paralysis is one of the common problems leading to facial deformation. COVID-19 virus rarely has been shown to be associated with facial palsy. Here we present a case of a 60-year-old woman who presented with features of left lower motor facial palsy signs along with common features suggestive of COVID-19 infection. Brain imaging did not reveal any pertinent pathology but her polymerase chain reaction for COVID-19 was positive. This case highlights the fact that acute COVID-19 infection can be considered a cause of motor neuron facial palsy in the ongoing pandemic of COVID-19. Cases with neurological features suggestive of facial palsy therefore should be suspected of acute COVID-19 infection based on other pertinent findings of COVID-19 infection and thus polymerase chain reaction testing should be done., Keywords: case reports; COVID-19; facial palsy.

Background: Multiple sclerosis (MS) can present with facial symptoms and signs, such as facial palsy, myokymia, and hemifacial spasm. Considering the importance of early diagnosis, treatment, and exclusion of causes other than MS, we aimed to assess the prevalence of these disorders in patients with MS., Methods: MS patients who were referred to the Isfahan MS clinic from March 2021 to March 2022 were observed for facial presentations of the disease. A checklist of patients' baseline characteristics and disease features were then completed through patient interview and medical files., Results: Of the total of 2260 MS patients who were assessed, 3.27% had facial palsy, 1.28% had myokymia, and 0.84% presented with hemifacial spasm. The mean age of facial symptom onset was 30.74, 29.07, and 31.37 years, respectively. No relationship was found between the type of facial presentation and factors such as age, gender, subtype of MS, affected side of face, and time of presentation., Conclusion: On the grounds that facial disorders can be the first presentation of MS, patients with atypical features of other common facial diseases such as Bell's palsy should therefore be carefully assessed and followed for any clues pertaining to the diagnosis of MS., Competing Interests: Declaration of Competing Interests None., (Copyright © 2022. Published by Elsevier B.V.)

Objective: Acute facial palsy is a consequence of various diseases, with the number of patients increasing with advancing age. This study aimed to analyse the clinical characteristics of acute peripheral facial palsy in older adults., Methods: A total of 30 patients with a mean age of 68.4 ± 9.1 years were included in the study. All patients received a standardised investigation and follow up. The hospital charts of the patients with acute facial palsy were reviewed retrospectively., Results: The predominant causes of acute facial palsy in older adults were: Bell's palsy, Ramsay Hunt syndrome, trauma, otitis media and malignancy. At baseline, complete and incomplete facial palsies were seen in 26.7 per cent and 73.3 per cent of patients, respectively. The overall rates of good recovery, partial recovery and no recovery were 66.7 per cent, 10 per cent and 23.3 per cent, respectively. Increased age led to a significantly lower level of recovery in older adults., Conclusion: Bell's palsy and Ramsay Hunt syndrome were the most common aetiologies of acute facial palsy in older adults, and such patients are likely to have incomplete recovery. Active early treatment is necessary for achieving good outcomes in older adults.

Our patient presented with symptoms consistent with Bell's palsy. The involved cranial nerves were the facial and oculomotor nerves. She had preceding upper respiratory tract infection symptoms. She had no risk factors or significant illnesses, and no other causes were found. Although there are reported cases of multiple cranial nerves affected in Bell's palsy, our review of literature revealed no prior cases of involvement of the parasympathetic oculomotor fibres in Bell's palsy., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Limited 2022. No commercial re-use. See rights and permissions. Published by BMJ.)

Bell's palsy is the most common mononeuropathy that causes acute unilateral facial paralysis or paresis. The condition peaks within 72 h and may be associated with numerous signs and symptoms, including post-auricular pain, drooping of the eyelid, loss of taste sensation and decreased lacrimation. Although the etiology of the condition is unknown, inflammation, viral infection, ischemia and anatomy of the facial nerve have all been implicated in the pathophysiology of the disease. Diagnosis and determination of etiology are significant in the early management of this condition. Most incidents resolve spontaneously; however, treatment reduces cases of incomplete recovery and entails the use of corticosteroids, with a possible role for antivirals if a viral etiology is suspected. For patients with incomplete recovery, long-term complications have esthetic, physiological and psychological implications, which greatly affect their quality of life. The purpose of this article is to summarize the current literature on etiology, diagnosis and management of Bell's palsy.

Background and Purpose: With the progression of coronavirus infectious disease 2019 (COVID-19), various neurological manifestations have been noticed in infected patients, and Bell's Palsy (BP) is one of the peripheral neuropathies among those. BP has been associated with various other viral agents. Its evidence in patients with COVID-19 signifies the possibility of association between BP and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). This research was undertaken to evaluate the number of published cases of BP as the only major neurological manifestation in patients with COVID-19 from March 2020 to December 2021 and to investigate the association of SARS-CoV-2 and BP., Methods: A systematic review of the published English literature was performed using an electronic search in the PubMed/Medline, Scopus, Research Gate, Research Square, and Google Scholar databases, using keywords such as "COVID-19" OR/AND "SARS-CoV-2" OR/AND "Bell's palsy" OR/AND "facial nerve palsy" OR/AND "neurological" OR/AND "manifestation"., Results: The search strategy revealed 32 relevant publications with a total of 46 patients. BP was the initial manifestation in 37% of cases, and in 63% of cases it developed after COVID-19 symptoms; 71.7% of cases showed complete recovery, and 21.7% showed only partial relief from BP., Conclusions: Although the number of documented cases in this research is low, evidence of BP as the only major neurological manifestation in patients with COVID-19 signifies an important clinical finding and the possibility of another viral etiology of BP. More evidence is needed to establish the exact correlation between these two entities., (© 2022 European Academy of Neurology.)

Competing Interests: Competing interests: None declared.

A man in his 70s presented with a 4-day history of bilateral frontal headache and heaviness of the face. He was unable to close either of his eyes, to wrinkle his forehead bilaterally and to raise either corner of his mouth. The patient was admitted with a diagnosis of bilateral facial palsy. From history, epidemiology, physical and laboratory findings, Bell's palsy was considered more probable than viral infection, Guillain-Barré syndrome and sarcoidosis. Oral administration of prednisolone, valacyclovir and mecobalamin were initiated promptly, which improved his symptoms. In areas in which Lyme disease is not endemic, we believe that Bell's palsy is the most probable cause of isolated bilateral facial palsy. Patients with bilateral facial paralysis under the suspicion of Bell's palsy should be immediately started on steroid therapy., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Limited 2022. No commercial re-use. See rights and permissions. Published by BMJ.)

Background and Objectives: To describe the etiology and clinical course of pediatric acute-onset unilateral peripheral facial palsy (FP), to define factors that distinguish Bell's palsy from Lyme-related FP (LRFP), and to determine if early corticosteroid use impacts facial strength recovery in Bell's palsy or LRFP., Methods: Retrospective cohort study of children 1 to 18 years old who received clinical care within our pediatric clinical care network (Lyme-endemic region) between 2013 and 2018 for acute-onset unilateral peripheral FP., Results: The study included 306 children; 82 (27%) had LRFP, 209 (68%) had Bell's palsy, and 15 (5%) had FP of different etiology. Most children with LRFP presented between June and November (93%), and compared with Bell's palsy, more often had a preceding systemic prodrome, including fever, malaise, headache, myalgias, and/or arthralgias (55% vs 6%, P < .001). Neuroimaging and lumbar puncture did not add diagnostic value in isolated FP. Of the 226 children with Bell's palsy or LRFP with documented follow-up, FP was resolved in all but 1. There was no association between ultimate parent/clinician assessment of recovery and early corticosteroid use., Conclusions: Bell's palsy and LRFP were common causes of pediatric FP in our Lyme endemic region. Systemic prodrome and calendar month may help distinguish LRFP from Bell's palsy at FP onset, guiding antibiotic use. Early corticosteroid use did not impact our measures of recovery, although subtle abnormalities may not have been appreciated, and time to recovery could not be assessed. Future prospective studies using standardized assessment tools at regular follow-up intervals are necessary., (Copyright © 2022 by the American Academy of Pediatrics.)

Objective: This study evaluated the effects of the diameter of facial canal segments on the ipsilateral recurrence of idiopathic peripheral facial paralysis., Method: This study enrolled 20 patients with ipsilateral recurrent idiopathic peripheral facial paralysis. Measurements were made at the meatal foramen and mid-level of the labyrinthine segment and the narrowest and widest diameters of the mastoid and tympanic segments using the curved planar reformation technique with high-resolution computed tomography., Results: The diameters of the labyrinthine segment measured at the meatal foramen and mid-level segments and the narrowest and widest diameters of the tympanic and mastoid segments on the recurrent paralytic side were significantly smaller than the diameters of the segments on the healthy side., Conclusion: The narrowness of the facial canal segments may be a risk factor in recurrent idiopathic peripheral facial paralysis.

Background: The aetiology of idiopathic facial nerve palsy (Bell's palsy, BP) and sudden sensorineural hearing loss (SSNHL) are not known. It has been proposed that common respiratory tract viruses play a part in the pathophysiology of these diseases., Objectives: The incidence of many infectious diseases decreased during the lockdown of the society that took place during the COVID-19 pandemic. We investigated a possible change in the incidence of BP and SSNHL during the lock-down., Material and Methods: We searched the patient records for all BP and SSNHL cases between 1 Jan 2017 - 31 Aug 2020 at the hospital district of Helsinki and Uusimaa that covers a population of about 1.2 million., Results: The mean monthly incidence on BP decreased during the COVID-19 pandemic lock-down. No change in the SSNHL incidence was discovered., Conclusions and Significance: There is reason to speculate that one aetiologic reason for BP are transmittable respiratory tract pathogens.

Background: Vaccinations are a cornerstone of preventative medicine in the USA. However, growing concerns regarding facial nerve palsy following vaccination exist., Objective: This study aims to assess the occurrence of facial palsy as reported by the Vaccine Adverse Event Reporting System (VAERS) database., Methods: A retrospective analysis of the VAERS database was performed for cases of 'Facial Palsy', 'Bell's Palsy', 'Facial Paralysis' and 'Ramsay Hunt Syndrome' between 2009 and 2018. Subgroup analysis was performed to determine gender, age, history of facial palsy, type of vaccine used, number of days until onset of symptoms and overall facial palsy rate., Results: Nine hundred and forty-four entries met our inclusion criteria with 961 vaccine administrations resulting in facial paralysis. Facial palsy following vaccinations was evenly distributed across all age cohorts with two peaks between 60 and 74 years old and between 0 and 14 years old. Most patients were female (N = 526, 55.7%) without a reported history of facial palsy (N = 923, 97.8%). In 2009, reported incidence rate was 0.53%, as compared with 0.23% in 2018. The influenza vaccine had the greatest number of cases (N = 166, 17.3%), followed by the varicella (N = 87, 9.1%) and human papillomavirus vaccines (N = 47, 4.9%)., Conclusions: With the SARS-CoV-2 pandemic and recent approvals of the vaccinations, there is growing concern of facial palsy following vaccination. Although it is a known adverse event following vaccination, the likelihood of facial palsy following vaccination is low, with only 0.26% of overall reported cases over a 10-year span., (© The Author(s) 2021. Published by Oxford University Press. All rights reserved.For permissions, please e-mail: journals.permissions@oup.com.)

Competing Interests: We declare no competing interests.

Introduction: The prognosis of Bell's palsy, idiopathic facial nerve palsy (FNP), is usually predicted by electroneuronography in subacute phase. However, it would be ideal to establish a reliable and objective examination applicable in acute phase to predict the prognosis of FNP. Immune-nutritional status (INS) calculated from peripheral blood examination is recently reported as the prognostic factor in various disease. However, the validity of INS as the prognostic factor in Bell's palsy is not well known. Thus, we conducted a retrospective study to investigate the usefulness of INS as prognostic predictors of Bell's palsy., Methods: We reviewed the medical records of 79 patients with Bell's palsy and divided into two groups as "complete recovery" and "incomplete recovery" groups. Clinical features such as severity of FNP and INS, including neutrophil-lymphocyte ratio (NLR), lymphocyte-monocyte ratio (LMR), prognostic nutritional index (PNI), and controlling nutrition status (CONUT) score, were assessed., Results: In univariate analysis, statistically significant differences were observed in clinical score of facial movement, NLR, LMR, PNI, and CONUT score at the initial examination between the two groups (p < 0.05). Furthermore, in multivariate analysis, statistically significant differences were also observed in facial movement score and PNI at the initial examination (p < 0.05)., Conclusion: Immune and nutritional condition play important roles in the pathogenesis of Bell's palsy, suggesting that INS would be one of the useful prognostic factors in Bell's palsy., (© 2022 S. Karger AG, Basel.)

Background: Bell's palsy is a rare adverse event reported in clinical trials of COVID-19 vaccines. However, to our knowledge no population-based study has assessed the association between the inactivated SARS-CoV-2 vaccines and Bell's palsy. The aim of this study was to evaluate the risk of Bell's palsy after BNT162b2 and CoronaVac vaccination., Methods: In this case series and nested case-control study done in Hong Kong, we assessed the risk of Bell's palsy within 42 days following vaccination with BNT162b2 (Fosun-BioNTech [equivalent to Pfizer-BioNTech]) or CoronaVac (from Sinovac Biotech, Hong Kong) using data from voluntary surveillance reporting with the Hospital Authority, the COVID-19 Vaccine Adverse Event Online Reporting system for all health-care professionals, and the Hospital Authority's territory-wide electronic health records from the Clinical Data Analysis and Reporting System. We described reported cases of Bell's palsy among vaccine recipients (aged 18-110 years for CoronaVac and aged 16-110 years for BNT162b2). We compared the estimated age-standardised incidence of clinically confirmed cases among individuals who had received the CoronaVac or BNT162b2 vaccination (up to 42 days before presentation) with the background incidence in the population. A nested case-control study was also done using conditional logistic regression to estimate the odds ratio (OR) for risk of Bell's palsy and vaccination. Cases and controls were matched (1:4) by age, sex, admission setting, and admission date., Findings: Between February 23 and May 4, 2021, 451 939 individuals received the first dose of CoronaVac and 537 205 individuals received the first dose of BNT162b2. 28 clinically confirmed cases of Bell's palsy were reported following CoronaVac and 16 cases were reported following BNT162b2. The age-standardised incidence of clinically confirmed Bell's palsy was 66·9 cases per 100 000 person-years (95% CI 37·2 to 96·6) following CoronaVac vaccination and 42·8 per 100 000 person-years (19·4 to 66·1) for BNT162b2 vaccination. The age-standardised difference for the incidence compared with the background population was 41·5 (95% CI 11·7 to 71·4) for CoronaVac and 17·0 (-6·6 to 40·6) for BNT162b2, equivalent to an additional 4·8 cases per 100 000 people vaccinated for CoronaVac and 2·0 cases per 100 000 people vaccinated for BNT162b2. In the nested case-control analysis, 298 cases were matched to 1181 controls, and the adjusted ORs were 2·385 (95% CI 1·415 to 4·022) for CoronaVac and 1·755 (0·886 to 3·477) for BNT162b2., Interpretation: Our findings suggest an overall increased risk of Bell's palsy after CoronaVac vaccination. However, the beneficial and protective effects of the inactivated COVID-19 vaccine far outweigh the risk of this generally self-limiting adverse event. Additional studies are needed in other regions to confirm our findings., Funding: The Food and Health Bureau of the Government of the Hong Kong Special Administrative Region, China., Translation: For the Chinese translation of the abstract see Supplementary Materials section., Competing Interests: Declaration of interests EYFW has received research grants from the Food and Health Bureau of the Government of the Hong Kong Special Administrative Region, and the Hong Kong Research Grants Council, outside the submitted work. CSLC has received grants from the Food and Health Bureau of the Hong Kong Government, Hong Kong Research Grant Council, Hong Kong Innovation and Technology Commission, Pfizer, IQVIA, and Amgen; and personal fees from PrimeVigilance; outside the submitted work. FTTL has been supported by the RGC Postdoctoral Fellowship under the Hong Kong Research Grants Council and has received research grants from the Food and Health Bureau of the Government of the Hong Kong Special Administrative Region, outside the submitted work. EWYC reports honorarium from Hospital Authority; and grants from Research Grants Council (RGC, Hong Kong), Research Fund Secretariat of the Food and Health Bureau, National Natural Science Fund of China, Wellcome Trust, Bayer, Bristol-Myers Squibb, Pfizer, Janssen, Amgen, Takeda, and Narcotics Division of the Security Bureau of the Hong Kong Special Administrative Region, outside the submitted work. XL has received research grants from the Food and Health Bureau of the Government of the Hong Kong Special Administrative Region; research and educational grants from Janssen and Pfizer; internal funding from the University of Hong Kong; and consultancy fees from Merck Sharp & Dohme, unrelated to this work. ICKW reports research funding outside the submitted work from Amgen, Bristol-Myers Squibb, Pfizer, Janssen, Bayer, GSK, Novartis, the Hong Kong Research Grants Council, the Food and Health Bureau of the Government of the Hong Kong Special Administrative Region, National Institute for Health Research in England, European Commission, and the National Health and Medical Research Council in Australia; has received speaker fees from Janssen and Medice in the previous 3 years; and is an independent non-executive director of Jacobson Medical in Hong Kong. All other authors declare no competing interests., (Copyright © 2022 Elsevier Ltd. All rights reserved.)