One proposed cause of<unk>  cysts is ingrown hair, although hairs found in<unk>  sinus tracts may originate from the head. Excessive sitting is thought to predispose people to the condition, as sitting increases pressure on the coccygeal region. Trauma is not believed to cause a<unk>  cyst; however, such an event may result in inflammation of an existing cyst; there are cases where this can occur months after a localized injury to the area. Some researchers have proposed that<unk>  cysts may be caused by a congenital<unk>  dimple. Excessive sweating can also contribute to the formation of a<unk>  cyst: moisture can fill a stretched hair follicle, which helps create a low-oxygen environment that promotes the growth of anaerobic bacteria, often found in<unk>  cysts. The presence of bacteria and low oxygen levels hamper wound healing and exacerbate a forming<unk>  cyst.
Pilonidal disease
Hidradenitis suppurativa
Cystitis glandularis
Folliculitis
Vulvar vestibulitis
Anorectal abscess
Haemolacria
Urachal cancer