Hidden hair disease

Hidden hair disease, also known as pilonidal sinus, is a rare sinus that contains hair on the skin. This type of sinus is most commonly found on the dorsal side of the coccyge in the back of the anus. The condition was reported by Anderson as early as 1847. In 1880 Hodges officially adopted its current name. During World War II, the incidence of this disease increased significantly among US and British soldiers. These patients have long experience of riding a jeep. People think that this kind of sitting with bent legs and long-term bumps may be related to the disease, so they are called "jeep disease".