Question
My child has a small opening on the earlobe that often becomes red, swollen, and itchy. Examination shows they have a preauricular sinus tract. What are the causes of preauricular sinus tract?
Answer
Congenital preauricular sinus tract is caused by improper fusion of the first and second branchial arches during embryonic development or incomplete closure of the first branchial cleft. The sinus tract is a blind tube that can have branches and is often located on the upper part of the antihelix. The lumen is lined with stratified squamous epithelium and contains scale-like particles. When infected, it becomes red, swollen, painful, and may become purulent, with recurrent episodes. This condition is an incomplete expression of an autosomal dominant genetic disease.