Hidradenitis suppurativa: viewpoint on clinical phenotyping, pathogenesis and novel treatments.

Hidradenitis suppurativa (HS) is an inflammatory, debilitating follicular skin disease with recurring flare-ups. The painful, deep-seated, inflamed lesions in the inverse areas of the body cause severe discomfort, and hence, serious psycho-social and economic costs. HS is common, but often misdiagnosed and mechanistically poorly understood. Furthermore, HS is notoriously difficult to treat resulting in a high unmet medical need. To provoke debate, rational experimentation and initiate strategic studies, we here present a concise viewpoint on seven topics: the diagnosis of HS, the role of mechanical friction, the critical importance of accurate clinical subgrouping, smoking and obesity, the role of bacteria, and our comprehensive view on HS pathogenesis with a central role for keratin clearance, and novel treatment approaches.