This seemingly minor disease process has physicians baffled, as demonstrated by the multiple theories of its etiology and management in the current literature. Congenital and acquired theories of etiology have been proposed. For a time, the entity was referred to as Jeep rider's disease. It caused more than 80,000 US Army soldiers to be hospitalized during WWII and accounted for 4.2 million sick days. Much of the information we have about the disease comes from the military.
Presentations range from asymptomatic pits in the intergluteal region to painful draining lesions.
Congenital theories dominate in the first 70 years of the literature. These theories suggest that pilonidal sinuses are vestigial structures, cystic remnants of the medullary canal or the result of dermal inclusions caused by faulty development of the median coccygeal raphe. It has since been established that pilonidal disease is an acquired condition involving midline pits in the natal cleft. These holes or pits are enlarged hair follicles in the skin. The nature of these distorted hair follicles is unclear.