Metformin in Hidradenitis Suppurativa: Is It Worth Pursuing Further?

Hidradenitis suppurativa (HS) often coexists with obesity, metabolic syndrome, diabetes mellitus, or impaired glucose tolerance and insulin resistance and polycystic ovarian syndrome. Metformin is a medication used for the treatment of diabetes, acting in multiple ways. There is evidence that it decreases inflammatory cytokines, some of which are implicated in the pathogenesis of HS (TNF-alpha, IL-17). We performed a systematic review of data regarding the efficacy and safety of metformin for the treatment of HS. Four electronic databases (MEDLINE, ScienceDirect, Cochrane Library, and ClinicalTrials.gov), as well as the abstracts compendia of major dermatologic congresses, were searched. A total of 133 patients received metformin for HS across 6 studies, 117 of whom received it as monotherapy. The great majority of participants were female, in their thirties and overweight or obese, with one study including only children. The efficacy tools employed varied widely. Four studies (106 patients) documented improvement, 1 documented treatment failure, and 1 had mixed results. Only mild and transient side effects were noted. Metformin has been tried in few HS patients with acceptable efficacy in a fair number of them. As it is generally well tolerated and reasonably priced, carefully designed clinical trials comparing it with placebo are worth performing.