Hidradenitis Suppurativa is a painful, chronic skin disease characterized by recurrent inflamed nodules and abscesses, which may rupture to form fistulas and subsequent scarring. This Study is an open-label extension study available to subjects who participated in a prior adalimumab study who meet all the inclusion and none of the exclusion criteria. The purpose of this study to evaluate the long term safety, tolerability and efficacy of adalimumab in subjects with moderate to severe HS.