title: Psoriasis, psoriatic arthritis, and rheumatoid arthritis: Is all inflammation the same?
abstract: To review the pathophysiology, co-morbidities, and therapeutic options for psoriasis, psoriatic arthritis and rheumatoid arthritis in order to further understand the similarities and differences in treatment paradigms in the management of each disease. New targets for individualized therapeutic decisions are also identified with the aim of improving therapeutic outcome and reducing toxicity.
  
  
  
  Using the PubMed database, we searched literature published from 2000 to 2015 using combinations of the key words "psoriasis," "psoriatic arthritis," "rheumatoid arthritis," "pathogenesis," "immunomodulation," and "treatment."
  
  
  
  This was a non-systematic review and there were no formal inclusion and exclusion criteria.
  
  
  
  Abstracts identified in the search were screened for relevance and articles considered appropriate evaluated further. References within these selected articles were also screened. Information was extracted from 198 articles for inclusion in this report.
  
  
  
  There was no formal data synthesis. Articles were reviewed and summarized according to disease area (psoriasis, psoriatic arthritis, and rheumatoid arthritis).
  
  
  
  The pathophysiology of psoriasis, psoriatic arthritis, and rheumatoid arthritis involves chronic inflammation mediated by pro-inflammatory cytokines. Dysfunction in integrated signaling pathways affecting different constituents of the immune system result in varying clinical features in the three diseases. Co-morbidities, including cardiovascular disease, malignancies, and non-alcoholic fatty liver disease are increased. Increased understanding of the immunopathogenesis allowed development of targeted treatments; however, despite a variety of potentially predictive genetic, protein and cellular biomarkers, there is still significant unmet need in these three inflammatory disorders.
authors.affiliation: Faculty of Medicine and Health, Leeds Institute of Rheumatic and Musculoskeletal Medicine, University of Leeds, 2nd Floor, Chapel Allerton Hospital, Harehills Lane, Leeds LS7 4SA, UK.
authors.forename: Laura C
authors.initials: LC
authors.lastname: Coates
authors.affiliation: Department of Rheumatology, St Vincent's University Hospital and Conway Institute, University College, Dublin, Ireland.
authors.forename: Oliver
authors.initials: O
authors.lastname: FitzGerald
authors.affiliation: Faculty of Medicine and Health, Leeds Institute of Rheumatic and Musculoskeletal Medicine, University of Leeds, 2nd Floor, Chapel Allerton Hospital, Harehills Lane, Leeds LS7 4SA, UK. Electronic address: P.Helliwell@leeds.ac.uk.
authors.forename: Philip S
authors.initials: PS
authors.lastname: Helliwell
authors.affiliation: Larrey Hospital, Paul Sabatier University, Toulouse, France.
authors.forename: Carle
authors.initials: C
authors.lastname: Paul
mesh_terms: D018501:Antirheumatic Agents / Q000627:therapeutic use; D015535:Arthritis, Psoriatic / Q000188:drug therapy / Q000276:immunology*; D001172:Arthritis, Rheumatoid / Q000188:drug therapy / Q000276:immunology*; D016207:Cytokines / Q000276:immunology*; D006801:Humans; D007249:Inflammation / Q000276:immunology*; D058990:Molecular Targeted Therapy; D011565:Psoriasis / Q000188:drug therapy / Q000276:immunology
chemical_list: D018501:Antirheumatic Agents; D016207:Cytokines
keywords: Inflammation; Psoriasis; Psoriatic arthritis; Rheumatoid arthritis