title: Hidradenitis suppurativa associated with spondyloarthritis -- results from a multicenter national prospective study.
abstract: OBJECTIVE
  To determine the prevalence and characterize the inflammatory musculoskeletal symptoms of hidradenitis suppurativa (HS), a chronic inflammatory disease of skin appendages.
  
  
  METHODS
  Patients with HS referred to 3 dermatology university hospital centers were systematically screened for peripheral arthritis, dactylitis, inflammatory back pain, or enthesitis. After careful clinical examination, patients were further classified according to clinical and imaging criteria for spondyloarthritis (SpA) using the Amor, European Spondyloarthropathy Study Group (ESSG), and ASsessment in ankylosing spondylitis (ASAS).
  
  
  RESULTS
  We screened 640 patients with HS; 184 had musculoskeletal symptoms. In all, 43 (mean age 39.4 yrs, ± 8.3; 80% women) had arthritis, inflammatory back pain, or enthesitis and were investigated further. Signs of HS preceded the onset of articular symptoms in 39 patients (90%), at a mean interval of 3.6 years. A total of 18 (41%), 24 (55%), and 15 (34%) patients fulfilled the Amor, ESSG, and ASAS criteria, respectively, while synovitis, acne, pustolosis, hyperostosis, and osteitis (SAPHO) syndrome was established in 4 patients. The crude prevalence of SpA in all 640 patients with HS was 3.7% by the ESSG criteria.
  
  
  CONCLUSIONS
  SpA may occur in patients with HS, with the prevalence in this group exceeding that in the general population. The very short time between skin and joint symptom onset in some cases suggests common pathogenic mechanisms underlying HS and SpA.
authors.affiliation: From the Assistance Publique-Hôpitaux de Paris (AP-HP), Hôpital Lariboisière, Pôle appareil locomoteur, Fédération de Rhumatologie; University Paris Diderot, Sorbonne Paris Cité, Paris, France; Universitat Autonoma de Barcelona, Departament de Medicina, Barcelona, Spain; AP-HP, Hôpital Saint-Louis, Service de Dermatologie, Immunité anti virale, Biothérapie et Vaccins; Institut Pasteur, Sorbonne Paris Cité, Université Paris Diderot; AP-HP, Hôpital Bichat, Service de Rhumatologie; Université Paris Diderot, Sorbonne Paris Cité; Institut Pasteur, Centre médical, Paris; Service de Rhumatologie, Service de Dermatologie, Université de Franche-Comté, Besançon-Inserm, UMR S606, Centre Viggo Petersen, Hôpital Lariboisière; AP-HP, Hôpital Saint-Louis, Service de Dermatologie, INSERM U781, Hôpital Necker Enfants-Malades, Sorbonne Paris Cité Université, Paris Diderot, Paris, France.
authors.forename: Pascal
authors.initials: P
authors.lastname: Richette
authors.forename: Anna
authors.initials: A
authors.lastname: Molto
authors.forename: Manuel
authors.initials: M
authors.lastname: Viguier
authors.forename: Karen
authors.initials: K
authors.lastname: Dawidowicz
authors.forename: Gilles
authors.initials: G
authors.lastname: Hayem
authors.forename: Aude
authors.initials: A
authors.lastname: Nassif
authors.forename: Daniel
authors.initials: D
authors.lastname: Wendling
authors.forename: François
authors.initials: F
authors.lastname: Aubin
authors.forename: Frédéric
authors.initials: F
authors.lastname: Lioté
authors.forename: Hervé
authors.initials: H
authors.lastname: Bachelez
mesh_terms: D000328:Adult; D015897:Comorbidity; D005260:Female; D017497:Hidradenitis Suppurativa / Q000453:epidemiology*; D006801:Humans; D008297:Male; D008403:Mass Screening; D008875:Middle Aged; D015995:Prevalence; D011446:Prospective Studies; D025241:Spondylarthritis / Q000453:epidemiology*
keywords: ARTHRITIS; DACTYLITIS; ENTHESITIS; HIDRADENITIS SUPPURATIVA; SAPHO SYNDROME; SPONDYLOARTHRITIS