Study of Risk Factors for the Burning Mouth Syndrome in Patients Visiting the Khyber College of Dentistry Peshawar KPK: A Cross-Sectional Study

INTRODUCTION

Although its clinical appearance lacks any universally accepted definition,1 it is referred with different names as scalded mouth syndrome, stomatodynia sore tongue, burning lip syndrome, oral dysesthesia, glossopyresis, etc is burning mouth syndrome (BMS).1,2 The International Association for the Study of Pain8 defines Burning Mouth Syndrome (BMS) as "burning pain in the tongue or other mucous membrane associated with normal signs and laboratory findings lasting at least 4-6 months." BMS is an idiopathic condition with unclear pathogenesis,3 lack an appropriate and consistent classification, 4definitive diagnostic criteria, and awareness among oral health care professionals.5 Thus, the only means of a definitive diagnosis of this condition is via an intricate history taking and exclusion of all other pathologies that mimic this condition.⁶

The overall prevalence of this condition from various international studies ranges from 4% - 15%.^7,8

It is a disorder of middle-aged and elderly individuals with an age range of 38-72 years.3 It has never been reported in children and adolescents.9 It exhibits more female predilection, especially in post-menopausal women, with male-to-female ratio varying from 3:1 to 16:1 in different literatures.8,9,10 Although it is important to mention that such wide, variation has resulted from governing factors, like biological, physiological, and social factors.9,11 BMS is categorized as Primary (essential/idiopathic) in which the local and systemic factors cannot be ruled out via history taking or examination or secondary in which there is significant association with local and systemic/ psychological factors.10 Another classification divides BMS into three subtypes according to the variation in the pain (VAS) level over one day as follows: BMS Type 1: Burning increasing throughout the day and reaching its peak in the evening. BMS Type 2: complaint of continuous sensory disturbances. BMS Type 3: Intermittent symptoms with pain free periods during the day.¹¹

The clinical manifestation of BMS is variable and diversiform (burning, tingling, scalding, annoying, tenderness, or numbness).12 In many situations, the patient is unable to describe the chronic nature of perceiving sensations with BMS.13 Pain may be specific to some part of oral mucosa, often spontaneous and bilateral with no definite cause. It may accompany bitter/metallic taste (70%), Xerostomia, headaches, TMJ pain, stress, anxiety, depression, and less social contact with society.^14,15,16

The aetiology of BMS is still debatable and multifactorial, with several local (reduced saliva flow, inflammation, parafunctional habits, etc) systemic (Anemia, diabetes, HCV, menopause, etc) and psychological factors (stress, anxiety, depression, panics, etc.) were strongly associated with BMS.^11,14

The various laboratory tests should be the part of diagnostic criteria for BMS and they include a basic metabolic panel for glucose, serum iron level, antinuclear antibodies, complete blood count, cytological smear for candidiasis, salivary flow rate, skin test for allergy, MRI for exclusion of central nervous pathology.¹⁴

Once diagnosed with BMS, the treatment is still very challenging.15 The practitioners try its level best to sway away the suffering of the patient in the form of topical (Clonazepam 1.0 mg, Capsicum rinse 0.02%, etc.) and systemic medication (Clonazepam 0.5-1.5mg, Gabapentin 300mg, Tricyclic antidepressants 10-30mg, Milnaciparin 15-100mg, etc.).15 Non-pharmacological treatments include cognitive behavioral therapy and acupuncture, etc.11,16 This study aimed to determine the prevalence of BMS among both genders and its associated factors in patients visiting the Khyber College of Dentistry. It helped the clinician to identify the potential risk factors for BMS and its timely prevention and management. This study has helped to identify areas for future investigations (associated factors) required for the accurate diagnosis of BMS.

METHODOLOGY

This cross-sectional study was carried out on patients visiting the Department of Oral Medicine, Khyber College of Dentistry, Peshawar KPK, for examination and diagnosis of chronically suffering pain in the oral cavity from January 2018 to January 2019. Ethical Approval was obtained from the Research and Development Cell, Khyber College of Dentistry via notification # 6087/RRB/KCD. Non-probability convenience sampling was used to collect the data for BMS. The calculated sample size was 119, using the anticipated population proportion of 0.097 with a confidence interval of 95% and a margin of error to be 0.05. Informed consent was obtained from all the patients willing to participate in the study. For proper diagnosis of BMS, it was necessary to record the demographic details (residence, age, gender, and occupation), etc. All details were taken on the specially designed proforma. To determine the age distribution for the BMS, the age was divided into five-decade age subgroups (20-30 years, 31-40 years, 41- 50 years, and 51-60 years, above 61 years). The patients were interviewed for the characteristics of pain, its origin, time of onset, site of onset, type of discomfort, and all the associated local (contact allergy, parafunctional habits, fissured tongue, lichen planus, candidiasis, depapillation of mucosa/tongue, etc.) and the systemic factors (Diabetes, post-menopause, anaemia, hypertension, etc.) were recorded on structured proforma. Before all the meticulous steps, written informed consent was taken from every participating individual. The exclusion criteria included, patients reporting connective tissue disorders (lupus erythematosus, rheumatoid arthritis, etc.), pain of odontogenic origin (reversible, irreversible pulpitis, periodontitis, crack tooth syndrome), recurrent aphthous ulceration, autoimmune disorders, pericoronitis, Trigeminal neuralgia, atypical facial pain etc because all these symptomatic conditions can be diagnosed via through certain objective tests. The inclusion criterion was defined by expert oral pathologist and maxillofacial surgeon, in the light of the International Association for the Study of Pain. It narrates the burning pain in the tongue or other mucosal areas associated with normal signs and laboratory findings lasting at least 4-6 months with no inference to sleep and did not get worsen on eating/drinking was diagnosed as BMS. The level of stress was recorded using the Perceived Stress Scale (PSS). After the formal completion of the proforma for BMS the data was entered in SPSS version 16.0IBM, SPSS, to derive the frequency and percentages for all numerical variables. The categories of the other qualitative variables were used to derive the association of co-variants/risk factors associated directly or indirectly with BMS. The chi-square test was used to determine the relationship between local and systemic factors associated with BMS with the level of significance p<0.05.

RESULTS

Among 119 patients, 67 males (56.30%) and 52 females (43.69%) were diagnosed with BMS. The overall male-to female ratio was found to be 2.35:1.67. The mean age group for BMS was 51±8 years. Both genders have clearly shown (n=54, 45.37%), advancing age (51-60 years) was acting as a risk factor for the occurrence of BMS. Table 1

In Table No 2 the nature, onset, frequency and site of the discomfort (pain) was calculated for both genders. The majority of the patients described the nature of the pain associated with BMS to be a burning sensation. (n=108, 90.75%) and had slow onset (n=84, 70.59%). Table 2

The frequency of the pain expressed by the patients of BMS was in a continuous pattern (n=77, 64.70%) and the site of discomfort was specific (dorsum of tongue/ buccal mucosa) in a majority of cases (n=78, 65.54%). Table 2 The frequency of the local and systemic factors were shown in figure I and II.

The most common local factor found to be associated with BMS in both genders was fissured (n=37, 31.09%)

 tongue followed by xerostomia (n=36, 30.25%). The relation was found to be significant between local factors and BMS with a p-value of 0.01. Table 3 The most common systemic illness was diabetes (n=23, 19.32%) in males, while in females majority were at a post-menopausal stage. Table 3

There was a significant relationship between systemic factors and BMS with a p-value of 0.001.

 The Perceived Stress Scale (PSS) was used for stress assessment in both genders. Psychologically females were more stressed (24, 20.16%), while males were found to be

depressed (25, 21.00%) all shown in Table 4. The association of the psychological elements with BMS also carried a significant relationship (P=0.02).

DISCUSSION

 Burning mouth syndrome is a condition that lacks universally accepted diagnostic criteria, any accurate epidemiological data, prevalence, and poor prognosis due to challenging management. The objective of this study was also to reveal the fact and figures that governed this clinical state and to emphasize upon gender predilection in the presentation of the BMS.

The prevalence of BMS in different literature was found to be 0.6-15% among both genders.3 The findings of Heir et al.1 and Aravindhan et al.17 were also in accordance with the above findings. But the study of De et al.8 and Renton16 has even shown that the occurrence of BMS was more in females than males. A study by Grushka18 has claimed, it seemed the prevalence increases with age in both genders but with significant female predilection and a ratio of 3:1 to 16:1. The present study was unique in this regard in that the findings were opposite to the above findings. The male ratio has suffered BMS more than females. This fact can be described in the light of regional differences, growing stresses, lack of appropriate treatment protocol and follow ups, growing poverty, lack of education etc.

A study of Grushka18 has found, the prevalence of BMS increases with age. Even the findings in the study of Aravindhan17 also showed that the occurrence of BMS was rare in patients under 30 years and never reported in children and adolescents. Heir and colleagues also determined, this chronic condition predominantly affects middle-aged women in the pre-and post-menopausal period, though the males can also be affected with female to male ratio of 7:1. In this study the findings correlate with the above studies but agrees more with the findings of Grushka. The male-to-female ratio  in this study clearly showed that the occurrence of this condition affects both genders with advancing age. In addition, the study of Popa15 also determined that BMS particularly affects post-menopausal women. According to Kia et al.19, BMS is more common in middle-aged and elderly females, which is in line with the findings of our study. The study by Cao20 and colleagues has proven that the discomfort was site-specific, and onset was spontaneous that gradually increased in intensity. In contrast to the findings in Grushka18 patients usually report no pain or burning sensation present at its lowest intensity upon awakening, starting after a meal of the day. Once initiated, it is continuous and reaches a maximum intensity by late evening. It never disturbs sleep. In this study, the BMS presented with a burning sensation and the onset of discomfort was slow, often continuous in nature and site-specific.

These findings were somehow found to be like Grushka.18 Popa and collaegues15 have proven that BMS is site specific especially the edge and top of the tongue. Gurvits et al.21 reports that BMS presents as a burning, scalding perception often high to severe intensity, commonly bilateral and involves the tongue, palate and lower lip. In the present study, the pain was also site-specific especially involving the tongue and buccal mucosa, which agreed well with all the above studies. Nevertheless, Popa15 claimed that half of the patients with BMS presented with pain of sudden onset and half were complaining the pain of continuous character.

In the study of Grushka in 2000 and 2002 along with his colleagues22 have observed, that patients with BMS also reported associated symptoms such as alteration in taste (Dysgeusia) and oral dryness (xerostomia). The findings in the present study have revealed that both genders manifested the burning sensation with altered taste and oral somatosensory perception, which correlated well with both above studies. In fact, this study also showed the fissured tongue to be strongly associated with BMS in both genders. The study of Lopez7 reported similar findings and claimed that BMS has affected the quality of life of patients due to associated symptoms. Popa along with colleagues15 again have shown that local factors in which 35.6% of patients with candidiasis had BMS followed by denture wearers. Allergy with epoxy resin and methyl methacrylate and 6.8% parafunctional habits (rubbing, rolling, and rotation) or clenching/bruxism have caused BMS of the oral mucosa. All these interesting facts were found to be significantly associated as risk factors with BMS in this present study. Renton16 was able to show that 36-60% of BMS patients had xerostomia. He described anxiety and depression that increased the chances of xerostomia. In this study, data correlated well with all the above findings. Both genders have shown the association of more than one lesion found  to be the cause of BMS. Lamaster and colleagues23 stressed upon taking a proper medical history and review of systems for the conditions like diabetes, anaemia, thyroid disease, pre or post menopausal status, drug history etc. as all these have direct and indirect effects to potentiate the BMS. Popa15 was able to find 70.3% of patients, displaying the presence of two or more concomitant factors to be associated with BMS. Post menopausal women and diabetes in men were important etiological factors in the genesis of BMS, which are in accordance with the findings in this study. The relationship between the medical history and BMS was found to be significant. However, in this study, post-menopausal status and diabetes were predominant risk factors found in females with BMS.

These findings were comparable to the findings in the literature, as BMS is more prevalent in females than males due to more distribution of systemic and local risk factors. According to Thoppay,5 anemia was found in 11.4% of cases having BMS. It has affected both genders and resulted in depapillation of the tongue, which was found to be the specific site for BMS. The present study, astonishingly have shown the same result. Anaemia was found to be associated in patients with BMS.

 The extensive research of Lamay6 and De8 have proven that the chronicity of this condition is depicted in irritability, stress, anxiety, and depression. It severely affects the quality of life and the patient's social interaction. Thus, it was able to highlight that BMS is a benign condition but yet difficult to manage due to chronic episodes of irritation.3All these findings were coherent with the present study. Both genders have shown the different levels of stress and depression that were associated with a burning sensation in the mouth. Popa has even claimed in his study that psychiatric disorders were even high than that found in the literature with BMS, as most cases are still hidden or undiagnosed.

CONCLUSION

 The predominant age group for the presentation of BMS between both genders were 51-60 years. The local and systemic risk factors were found to have a statistically significant relationship with the BMS. Among females, the most common local factor was candidiasis followed by xerostomia. The predisposing systemic factor in women was post-menopausal status. Among males, the most common local factor was also the same, but an association of more than one local factor were found to be involved in the genesis of the BMS. The most prevalent systemic factors in males were diabetes. The psychological element in the progression of BMS was found to be more obvious in both genders.

CONFLICT OF INTEREST

None to declare

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