When we think of rare physical traits, we often picture striking features that stand out. Yet some unusual traits are so small they go unnoticed—even by the person who has them. One example is the tiny hole or dimple near the top of the ear, known as a preauricular sinus. At first glance, it may look like a small birthmark or piercing, but it’s neither.
A preauricular sinus, also called a preauricular pit or fistula, is a small congenital opening that forms during early fetal development—around the sixth week of gestation. It happens when parts of the ear don’t fully fuse and is often hereditary, meaning it can run in families.
