HS Pathogenesis: Genetics, Friction, Microbiome, and Hormonal Drivers

Welcome back to another AJMC Insights series. In "HS Pathogenesis: Genetics, Friction, Microbiome, and Hormonal Drivers," Hadar Lev-Tov, MD opens the series on hidradenitis suppurativa.

Dr. Lev-Tov begins by calling HS the most common disease most clinicians have never heard about. He cites a global prevalence of roughly 1 percent, meaning about one in every 100 people has some degree of mild, moderate, or severe disease. Females were long thought to predominate about three to one. He notes that clinical trial data suggest clinicians may be missing males during diagnosis, and he says time will tell.

The cause remains unknown, but Dr. Lev-Tov describes a constellation of contributing elements. The first is genetic predisposition. No single gene explains the disease, though genes related to wound healing have been associated with HS, and he says new genes are being uncovered as the discussion is recorded.

Friction is the second element, because lesions concentrate in high-friction areas such as the axilla, the inframammary area, and the groin. Third, the microbiome in these areas shows dysbiosis compared with people without HS. He tells patients there are too many bad bacteria and too few good ones.

Hormonal changes are superimposed on all of this and act as a major driver early in the disease. HS often begins in the teenage years, and some women flare around their periods. This supports a hypothesis that hormones play a role, and targeting them seems to help.

Dr. Lev-Tov explains that friction, dysbiosis, and hormones layered on a genetic predisposition produce a massive inflammatory picture centered on the hair follicle. He stresses that these mechanisms are not merely theoretical, because they help clinicians design a treatment plan for each patient.

The next episode in this series, "HS Patient Journey: Clinical, Emotional, and Economic Burden," follows a young patient named Jessica and the clinical, emotional, and economic toll that HS can take.