Pilonidal cysts, active component, U.S. Armed Forces, 2000-2012.

Pilonidal cysts affect mainly young adults and prompted hospitalization for nearly eighty thousand U.S. soldiers during World War II. During the surveillance period of 2000 through 2012, there were 35,517 incident cases of pilonidal cyst among active component U.S. service members. Of cases arising in non-deployed service members (n=32,134), 6.7 percent (n=2,175) required hospitalization for care. The overall incidence rate was 1.9 cases per 1,000 person-years (p-yrs). Annual incidence rates of hospitalized and outpatient diagnoses of pilonidal cyst were stable during the period. Approximately 11 percent of incident cases suffered recurrences. Although pilonidal cyst is said to affect males more commonly than females, the incidence rates among male and female service members were similar (1.9 and 1.7 per 1,000 p-yrs, respectively). The proportion of female cases who later developed recurrent disease (11.7%) was higher than that of males (10.9%). Incidence rates decreased with advancing age, and rates were highest in recruits and junior enlisted service members compared to their respective counterparts. On average, there were 800 hospital bed days and 1,731 days of lost duty time each year associated with the diagnosis and treatment of pilonidal cysts.