Prevalence of commissural lip pits in population of central Gujarat: A hospital-based study.

BACKGROUND: Commissural lip pits (CLPs) fall among the rare congenital deformities recorded. CLP usually follows dominant hereditary pattern and may be associated with other congenital defects. CLP can appear as unilateral depression or bilateral depression.
OBJECTIVE: To assess the prevalence, age distribution, site and gender predilection of CLP in a central Gujarat population.
MATERIALS AND METHODS: Outdoor patients over a period of 6 months were examined for clinical evidence of CLPs.
RESULTS: A total of 14,403 patients were examined for the presence of CLP. CLP was identified in 381 patients with a prevalence of 2.65%. The occurrence of CLP was more in male patients. The maximum number of patients was in the age groups of 20-29 years. No significant statistical difference was observed in the distribution of CLP. Unilaterally distributed CLP was more common on the left side.
CONCLUSION: Our study showed 2.65% prevalence of isolated CLPs with a male predilection. There was almost equal distribution of unilateral and bilateral CLP. In unilateral cases, the left side was affected the most. Although literature says lip pits can be an associated feature of certain syndromes, there were no syndromic patients in our study.

INTRODUCTION

Lip pits are malformations of lips, often following hereditary pattern, possibly a dominant characteristic and may be associated with other congenital defects.[1] Lip pits can be of three types according to their location: commissural, median upper and median lower. Median lower lip pits are the most common among all.[2] Commissural lip pits (CLP) are small mucosal invaginations that occur at the corner of the mouth on the vermilion border.[3] CLP can appear as unilateral depression or more frequently as bilateral depression.[134] Prevalence rates of CLP in adults range from 0.3% to 21.1%[4567891011] [Table 1]. Prevalence studies of CLP in the Indian population are lacking. The purpose of this hospital-based study was to report the frequency of occurrence of CLPs among patients in central Gujarat state region.

Table 1

Prevalence of commissural lip pits in different population

MATERIALS AND METHODS

Permission to undertake the study was obtained from institutional ethics committee. A total of 14,403 patients over a period of 6 months, from June 2014 to December 2014, were examined for clinical evidence of CLPs. Diagnosis of CLPs was made on the basis of clinical examination. Study variables included age, gender and site of malformation.

Statistical analysis

Statistical analysis was done using STATA 13.1 Software by Stata Corp Ltd India Continent by applying Pearson Chi-square test and Fisher's exact test.

RESULTS

Out of 14,403 patients, 381 patients had CLP, with 2.65% prevalence. Age of the patients ranged from 4 to 81 years. Out of 381 patients, 135 (35.4%) were females and 246 (64.6%) were males [Graph 1]. Male: female ratio was 1.8:1. The maximum number of patients was in the age groups of 20–29 years (24.9%) [Graph 2]. Out of 381 patients having CLP, 188 (49.3%) patients had unilateral CLP [Figure 1] while 193 (50.7%) patients had bilateral CLP [Figure 2]. No significant statistical difference was observed in the distribution of CLP. Out of 188 patients having unilateral lip pits, 147 patients had CLP on the left side and 41 patients had CLP on the right side [Table 2]. No significant correlation was observed between unilateral/bilateral distribution as well as site-wise distribution of CLP with the gender (P > 0.05) [Graphs 3 and 4].

Graph 1

Gender-wise distribution

Graph 2

Age-wise distribution of Commissural lip pit in males and females

Figure 1

Unilateral commissural lip pit on the left side

Figure 2

Commissural lip pit bilaterally

Table 2

Site-wise distribution

Correlation of gender with distribution of Commissural lip pit

Correlation of gender with site of Commissural lip pit

DISCUSSION

Lip pits may result from notching of the lip at an early stage of development, with fixation of the tissue at the base of the notch or from the failure of complete union of the embryonic lateral sulci of the lip.[1] Their location suggests that they may represent a failure of normal fusion of maxillary and mandibular process.[3]

CLPs occur on the lip commissure lateral to the typical lip pits.[4] Lip pits can occur either as an isolated defect or in association with other developmental disturbances as popliteal pterygium syndrome,[12] Van der Woude syndrome,[13] oral-facial-digital syndrome and Marves and Cremer's syndrome.[14] CLP can be seen unilaterally or bilaterally on the corner of the mouth.[234]

CLP is a congenital malformation which may be misdiagnosed with lesions such as chronic angular cheilitis (CAC). CAC is a fungal infection of acquired origin. Reduced vertical dimensions lead to accentuated folds at the corner of mouth, thus favoring saliva pooling and fungal infections. Furthermore, in special children like Down syndrome, there is greater evidence of CAC because of continuous drooling of saliva because of muscle hypotonia. CAC can be differentiated from CLP on the basis of history.[1516]

In the present study, we found 2.65% overall prevalence of CLP. Our results were almost similar with the results of Sawyer et al.[5] and Ambika et al.[6] who found 2.9% and 3.5% prevalence of CLP, respectively. Our results showed disparity with results of Premakumar et al.,[4] Gorsky et al.,[7] Schaumann et al.,[8] and Freudenberger et al.[9] who found 0.3%, 17.4%, 21.13% and 8% overall prevalence of CLP, respectively.

Our study showed male predilection for CLP. Our results were consistent with Premakumar et al.[4] and Sedano et al.[10] Male:female ratio in the present study was 1.8:1 which was similar with results obtained by Premakumar et al.[4] but was not consistent with results of Sedano et al.[10] which was 1.05:1.

The maximum numbers of patients in the present study were in the age groups of 20–29 years. Our results were not in harmony with results of Premakumar et al.[4]

There was no significant statistical correlation observed in the distribution of CLP in the present study. Our results contradicted with the results of Premakumar et al.[4] and Gorsky et al.[7] who found the unilateral distribution of CLP to be more common.

In the present study, in the unilateral distribution of CLP, the left side was more commonly involved than the right side. Our results were in accordance with the results of Premakumar et al.[4]

CONCLUSION

This study provides prevalence of CLP in central Gujarat state population for the first time. Some similarities were observed between the present study and previous studies. The variation in frequency among studies reported in the literature can be attributed to racial or ethnic differences. Our study showed 2.65% prevalence of isolated CLPs with a male predilection. There was almost equal distribution of unilateral and bilateral CLP. In unilateral cases, the left side was affected the most. Though literature says lip pits can be an associated feature of certain syndromes, there were no syndromic patients in our study.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.