Prevalence and ethnic variation of pre-auricular sinuses in children

Pre-auricular sinus (PAS) describes a congenital ear malformation presenting as a pit or sinus that may become infected, often requiring antibiotics and/or surgical excision. Although the presentation of PAS in otolaryngology clinics is not uncommon, there is limited epidemiological data regarding this malformation in children. Some evidence also suggests a potential ethnic variation in prevalence rates and potential heritability patterns within families, however these have yet to be proven. This study is the first to use pediatric population level data to investigate prevalence rate, ethnic variation, and to explore the unproven hypotheses of a genetic basis of PAS.

In this prospective cross-sectional study, we enrolled 1106 subjects (mean age=6.8, male-to-female ratio=1.15:1) between June and September 2014. Subjects were recruited from B.C. Children's Hospital in Vancouver, Canada. Inclusion criteria was children <18 years of age; exclusion criteria was those seeking care for PAS. Subjects were visually inspected for the presence of PAS by clinical observers followed by verbal questionnaire (demographics, self-identified ethnicity, family history of PAS, chronic medical conditions). Data analysis utilized Pearson Chi-Square Test to determine the potential ethnic variation, and odds ratios of family history were used to determine a potential genetic basis.

26 (7 bilateral, 19 unilateral) of 1106 subjects were positive for PAS (2.4%). Using Pearson Chi-Square Test, a significant ethnic variation was found to exist (χ(2) (6,N=1106)=22.80, p<0.0001), with Asians having the highest prevalence (6.6%), followed by African Americans (4.5%), Middle Easterners (3.4%), First Nations (2.0%), and Caucasians (1.2%). None were found in South Asians (n=124) or Latin Americans (n=18). Subjects with positive family history of PAS had greater likelihood of having PAS (OR=16.7, 95% CI=7.3-38.5, p<0.0001). There was also stronger association between family history and bilateral PAS (OR=26.5, 95% CI=5.8-121.7, p<0.0001) compared to unilateral PAS (OR=12.2, 95% CI=4.6-32.5, p<0.0001).

This was the largest pediatric population level study to date, and showed the prevalence of PAS was 2.4% in this pediatric population, whose ethnic diversity was representative of B.C.'s community. A significant ethnic variation existed and associations between family history and PAS suggested a potential genetic basis, particularly with bilateral PAS.