It has been postulated that hair penetrates into the subcutaneous tissues through dilated hair follicles, which is thought to occur particularly in late adolescence, though follicles are not found in the walls of cysts. A sinus develops with a short tract, with a not clearly understood suction mechanism involving local anatomy, eventually leading to further penetration of the hair into the subcutaneous tissue.
This is done by numbing the area with a local anesthetic and making an incision with a scalpel over the infected area to open the abscess cavity. The pus is drained, and any accumulated hair and debris are removed. The wound is cleaned with saline solution, packed with gauze, and covered with a bandage. Antibiotics are generally not necessary unless signs of a spreading skin infection (cellulitis) are present. Pain medication will often be prescribed.
Research is going on in Mayo Clinic for proper removal of this cyst.