Question
My child has a small opening on the ear lobe, which often becomes red, swollen, and itchy. Examination has shown that they have a preauricular fistula. What are the causes of preauricular fistula?
Answer
Congenital preauricular fistula is a common otolaryngological condition. It is caused by improper fusion of the first and second branchial arches or incomplete closure of the first branchial cleft during the embryonic stage of ear formation. A fistula is a blind tube that can have branches and curves, with its external opening usually located above the antihelix of the ear lobe. The lumen is covered with stratified squamous epithelium, containing scales. When pressed around the fistula opening, there may occasionally be a small amount of sticky sebaceous material exuding from the fistula. Once infected, it becomes red, swollen, painful, and may ulcerate, with recurrent episodes. This condition is an incomplete expression of an autosomal dominant genetic disorder.