Hidradenitis suppurativa (HS) is a common and debilitating skin disease that is poorly understood and understudied. As a result, little is known about disease prognosis and few effective treatments exist for this condition. This prospective observational cohort study aims to comprehensively characterize the clinical and biological features of HS. The results of this research will provide a basis for the development of an HS clinical classification system and identification of potential treatments for HS.