Viral infection as a trigger of hidradenitis suppurativa disease activity: the role of SARS-CoV-2 infection in acute flares.

Hidradenitis suppurativa (HS) is a severe chronic relapsing inflammatory disorder of the hair follicle unit that affects intertriginous areas. Several studies have reported the occurrence of HS exacerbation following SARS-Cov2 vaccination. However, few data exist on the role of bacterial and viral infections in HS acute flares. The aim of the study was to investigate the occurrence of HS flares following SARS-Cov2 infection. We conducted a retrospective, single-centre, observational study at the Dermatology Clinic of Azienda Ospedaliero-Universitaria delle Marche between April 2020 and December 2022. Patients aged 18 years or older with a diagnosis of HS were included and completed a questionnaire in order to investigate the incidence and characteristics of HS manifestations after SARS-Cov2 infection. In total, 228 patients were enrolled; 143 (62.7%) reported at least one episode of SARS-CoV-2 infection, and 27.3% of patients with SARS-Cov2 infection experienced disease flares. Relapses were more frequently observed in patients with concomitant HS-related disease (flares vs no flares: 67% vs 43%; p=0.016), and the occurrence of flares negatively correlated with antibiotic treatment for HS during SARS-CoV-2 infection (flares vs no flares: 39% vs 20%; p=0.025). Although our data suggest that SARS-CoV-2 infection may act as a disease trigger in patients with HS, further studies are needed.