Upadacitinib for the management of refractory hidradenitis suppurativa, psoriasis, and pyoderma gangrenosum.

Dear Editor, Hidradenitis suppurativa (HS) is a chronic immune-mediated skin disease presenting with recurrent inflammatory nodules, abscesses, draining tunnels, and scarring, most commonly in intertriginous sites. Its estimated global prevalence is approximately 1% and its pathogenesis is complex, involving dysregulation of several pro-inflammatory cytokines, including tumor necrosis factor (TNF)-α and interleukin (IL)-17. HS frequently coexists with systemic inflammatory conditions, such as axial spondyloarthropathies and inflammatory bowel diseases (IBD). Additional associations with dermatologic diseases have been described, particularly with pyoderma gangrenosum (PG). Emerging evidence also suggests a potential link between HS and psoriasis, possibly due to overlapping cytokine pathways. When these conditions occur together, management becomes particularly challenging and may require therapeutic strategies targeting broad inflammatory networks. [...].