title: Hidradenitis suppurativa (HS): An unrecognized paradoxical effect of biologic agents (BA) used in chronic inflammatory diseases.
abstract: BACKGROUND
  Paradoxical hidradenitis suppurativa (HS) induced by biologic agents (BA) is scarcely reported.
  
  
  OBJECTIVE
  We sought to describe the clinical characteristics and outcome of patients developing paradoxical HS under BA.
  
  
  METHODS
  This was a multicenter nationwide retrospective study asking physicians to report all cases of HS, confirmed by a dermatologist, occurring during treatment of an inflammatory disease by a BA.
  
  
  RESULTS
  We included 25 patients (15 inflammatory rheumatism, 9 Crohn's disease, 1 psoriasis) treated by 5 BA (adalimumab = 12, infliximab = 6, etanercept = 4, rituximab = 2, tocilizumab = 1). Median duration of BA exposure before HS onset was 12 (range 1-120) months. Patients were mostly Hurley stage I (n = 13) or II (n = 11). Simultaneously to HS or within 1 year, 11 patients developed additional inflammatory diseases, including paradoxical reactions (psoriasis = 9, Crohn's disease = 3, alopecia areata = 1, erythema elevatum diutinum = 1). Complete improvement of HS was more frequently obtained after BA discontinuation or switch (n = 6/10, 60%) rather than maintenance (n = 1/14, 7%). Reintroducing the same BA resulted in HS relapse in 3 of 3 patients.
  
  
  CONCLUSIONS
  Retrospective nature and lack of complete follow-up for some patients are limitations.
  
  
  CONCLUSIONS
  HS is a rare paradoxical adverse effect of BA, but fortuitous association cannot be excluded in some cases. We observed a trend toward better outcome when the BA was discontinued or switched.
authors.affiliation: Dermatology Department, Hôpital Edouard Herriot, Université Claude Bernard Lyon I, Lyon, France. Electronic address: coline.faivre@gmail.com.
authors.forename: Coline
authors.initials: C
authors.lastname: Faivre
authors.affiliation: Dermatology Department, Hôpital Edouard Herriot, Université Claude Bernard Lyon I, Lyon, France.
authors.forename: Axel Patrice
authors.initials: AP
authors.lastname: Villani
authors.affiliation: Dermatology Department, Hôpital Saint-Jacques, Université de Franche-Comté, Besançon, France.
authors.forename: François
authors.initials: F
authors.lastname: Aubin
authors.affiliation: Dermatology Department, Centre Hospitalo-Universitaire (CHU) de Strasbourg, Université de Strasbourg, Strasbourg, France.
authors.forename: Dan
authors.initials: D
authors.lastname: Lipsker
authors.affiliation: Rheumatology Department, Center Hospitalier de Valence, Valence, France.
authors.forename: Martine
authors.initials: M
authors.lastname: Bottaro
authors.affiliation: Rheumatology Department, CHU Lapeyronie, Montpellier, France.
authors.forename: Jean-David
authors.initials: JD
authors.lastname: Cohen
authors.affiliation: Dermatology Department, Center Hospitalier de Valence, Valence, France.
authors.forename: François
authors.initials: F
authors.lastname: Durupt
authors.affiliation: Dermatology Department, CHU de Dijon, Dijon, France.
authors.forename: Géraldine
authors.initials: G
authors.lastname: Jeudy
authors.affiliation: Dermatology Department, CHU Henri-Mondor, Créteil, France.
authors.forename: Emilie
authors.initials: E
authors.lastname: Sbidian
authors.affiliation: Clinical Investigation Center for Biotherapy, Institut National de la Santé et de la Recherche Médicale (INSERM) Centre d'Investigation Clinique (CIC) 1431 and Rheumatology, Université de Franche-Comté, Besançon, France.
authors.forename: Eric
authors.initials: E
authors.lastname: Toussirot
authors.affiliation: Rheumatology Department, Hôpital Erasme, Université Libre de Bruxelles, Brussels, Belgium.
authors.forename: Valérie
authors.initials: V
authors.lastname: Badot
authors.affiliation: Dermatology Department, CHU Hôtel Dieu, Nantes, France.
authors.forename: Sébastien
authors.initials: S
authors.lastname: Barbarot
authors.affiliation: Dermatology Department, Center Hospitalier Lyon-Sud, Lyon, France.
authors.forename: Sébastien
authors.initials: S
authors.lastname: Debarbieux
authors.affiliation: Dermatology Department, Hôpital Claude-Huriez, Université Lille II, Lille, France.
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Delaporte
authors.affiliation: Hepatogastroenterology Department, Center Hospitalier Loire Vendée Océan, Challans, France.
authors.forename: Guetty
authors.initials: G
authors.lastname: Goegebeur
authors.affiliation: Rheumatology Department, CHU Lapeyronie, Université de Montpellier, Montpellier, France.
authors.forename: Jacques
authors.initials: J
authors.lastname: Morel
authors.affiliation: Infectious Diseases Center Necker-Pasteur, Pasteur Institute, Assistance Publique-Hôpitaux de Paris, Paris, France.
authors.forename: Aude
authors.initials: A
authors.lastname: Nassif
authors.affiliation: Dermatology Department, Hôpital Edouard Herriot, Université Claude Bernard Lyon I, Lyon, France.
authors.forename: Gérard
authors.initials: G
authors.lastname: Duru
authors.affiliation: Dermatology Department, Hôpital Edouard Herriot, Université Claude Bernard Lyon I, Lyon, France.
authors.forename: Denis
authors.initials: D
authors.lastname: Jullien
mesh_terms: D000068879:Adalimumab / Q000009:adverse effects; D000293:Adolescent; D000328:Adult; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000009:adverse effects*; D061067:Antibodies, Monoclonal, Humanized / Q000009:adverse effects; D001168:Arthritis / Q000188:drug therapy; D001688:Biological Products / Q000009:adverse effects*; D003424:Crohn Disease / Q000139:chemically induced / Q000188:drug therapy; D003875:Drug Eruptions / Q000209:etiology*; D057915:Drug Substitution; D000068800:Etanercept / Q000009:adverse effects; D005260:Female; D017497:Hidradenitis Suppurativa / Q000139:chemically induced*; D006801:Humans; D000069285:Infliximab / Q000009:adverse effects; D008297:Male; D008875:Middle Aged; D011565:Psoriasis / Q000139:chemically induced / Q000188:drug therapy; D012008:Recurrence; D012189:Retrospective Studies; D000069283:Rituximab / Q000009:adverse effects; D028761:Withholding Treatment; D055815:Young Adult
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D061067:Antibodies, Monoclonal, Humanized; D001688:Biological Products; D000069283:Rituximab; D000069285:Infliximab; D000068879:Adalimumab; C502936:tocilizumab; D000068800:Etanercept
keywords: biologic agents; hidradenitis suppurativa; paradoxical reactions; tumor necrosis factor-alfa inhibitors