HIDRADENITIS SUPPURATIVA WITH 20 OR MORE DRAINING TUNNELS: A NATION-WIDE RETROSPECTIVE STUDY.

Background: Hidradenitis Suppurativa (HS) is a chronic-relapsing, inflammatory skin disease of the terminal hair follicle, manifesting with nodules, abscesses and draining tunnels (dT) on intertriginous areas. Treatment options are limited and patients with elevated draining tunnels (dT) counts have been systematically excluded from published phase III studies. Methods: Data of HS patients with 20 or more dT were retrospectively collected. Results: 116 patients with 20 or more dT at any point during the course of the disease were included, 68 (58.62%) of whom were males. Seven of 116 (6.03%) patients had syndromic forms, including follicular occlusion triad (1) and PASH (6), yet pyoderma gangrenosum was documented in 13/116 (11.21%). 107 of 116 (92.24%) patients were treated with biologics. 102 patients with 20 or more dT were administered adalimumab, 12 received anti-IL17 agents, including secukinumab (9) and bimekizumab (3), and 9 were also offered off-label treatment options, including guselkumab (4), infliximab (3), risankizumab (1) and ustekinumab (1). At univariate regression analysis, gluteal involvement was a negative predictor of IHS4-55 achievement with adalimumab at 12-16, 52 and 104 weeks. Conclusions: The results of this study do not defy the conceptual basis that led to the introduction of a dT cutoff for clinical trial eligibility. Further research is needed to define the optimal approach for HS patients manifesting with 20 dT or more.