Swelling Near Tailbone

A swelling near the tailbone is most commonly a manifestation of pilonidal disease, presenting as an acute pilonidal abscess. This condition is an infection originating in the deep natal cleft, thought to be initiated by the penetration of loose hair into the skin, which creates a foreign body reaction and a sinus tract that can become blocked and infected. The result is a painful, red, fluctuant mass, typically located just off the midline in the sacrococcygeal area. While other rare conditions like presacral tumors can present in this region, the acute inflammatory signs of an abscess are the hallmark of pilonidal disease.