What is preauricular sinuses ? and why does my son have it

Birth defect: Pre-auricular pits or sinuses are remnants of fetal life & are thought to represent a second attempt to form a ear canal. It can exist as a simple dimpling or a tubular (sinus)tract.Most are cosmetic curiosities but some can become inflamed and need removal.

Pre-auricular cysts: Or sinuses are benign malformations from incomplete fusion of the "hillocks" that form the external ear ~ 6 weeks gestation. If pediatricians & ent's see other unusual facial or physical features, they obtain a renal ( kidney) ultrasound, brainstem auditory evoked response ( test for sensorineural deafness) & comparative genomic hybridization (genetic test to rule out syndromes). Check with them.

Opening front of ear: the ear lobe is formed from different 'pieces' and right before birth they fuse.there may be a tiny lack of fusion and that starts draining--this is called a preauricular sinus.it can get infected and if that is repititive an ENT surgeon needs to see it.