Observational case series on adalimumab-induced paradoxical hidradenitis suppurativa

Although the efficacy of TNF blockers has been demonstrated in hidradenitis suppurativa (HS), many paradoxical effects have also been described with TNF antagonists. We wished to describe patients with adalimumab (ADA)-induced paradoxical HS.This is a retrospective descriptive case series of four patients with ADA-induced paradoxical HS.All the patients had a good response to TNFa antagonist therapy at the time of HS occurrence. The time from TNFa antagonist initiation to HS onset or exacerbation ranged from a few weeks to 24 months. The outcome of HS was variable. Systemic antibiotics were required in all the cases to control HS. TNF blockers were continued in three cases with a switch to another anti-TNF class in one case. Switch to ustekinumab was prescribed in one patient with SA and Crohn's disease.Although the imputability of TNF blockers in paradoxical HS is still debatable, further research and observation are needed to confirm and distinguish patients with genetic and clinical predisposition in the onset or exacerbation of HS during anti-TNF treatment.