Fig. 1.

Potential mechanisms of hormones in hidradenitis suppurativa (HS), showing that (A) estrogen and progesterone naturally vary across the menstrual cycle, but (B) each of these sex hormones have sex-specific immune modulating actions, either by directly acting on transcription factors and gene expression in inflammatory cells or indirectly via incompletely understood mechanisms (via 16-$\alpha$ estrogen). This leads to TH1/TH17 polarization, which is well recognized as an inflammatory contributor to HS. The role of other sex hormones, including (C,D) dehydroepiandrosterone sulfate, insulin, and testosterone, is less completely understood in the setting of HS, and further mechanistic investigation is required. Red arrows indicate suppressive activity, yellow arrows indicate unknown activity, and green arrows indicate contributory activity.