title: Psoriasis and pustular dermatitis triggered by TNF-{alpha} inhibitors in patients with rheumatologic conditions.
abstract: BACKGROUND
  New onset or worsening of psoriasis has been reported in patients treated with tumor necrosis factor alpha (TNF-alpha) inhibitors for a variety of rheumatologic conditions. There is mounting evidence that a key innate immune pathway for triggering common human autoimmune disease, including psoriasis, involves plasmacytoid dendritic cell precursors (PDCs) and type 1 interferon (IFN) production. We present herein a case series with clinical and histopathologic evidence of psoriasis in patients with rheumatologic disease treated with TNF-alpha inhibitors. We propose that the cross regulation between TNF-alpha and IFN may have a role in the pathogenesis of this reaction.
  
  
  METHODS
  We observed new-onset psoriasis (n = 13) or severe exacerbation of psoriasis (n = 2) in 15 patients with a variety of rheumatologic conditions-rheumatoid arthritis (n = 13), psoriatic arthritis (n = 1), and seronegative arthritis (n = 1)-during treatment with etanercept (n = 6), infliximab (n = 5), and adalimumab (n = 4). Immunohistochemical staining of skin biopsy specimens for myxovirus-resistance protein A (MxA, a surrogate marker for lesional type 1 IFN activity) showed increased staining in TNF-alpha inhibitor-induced psoriasis compared with psoriasis vulgaris.
  
  
  CONCLUSIONS
  New onset or severe exacerbation of psoriasis is a rare complication of TNF-alpha inhibitor therapy. The finding of increased production of IFN-alpha in TNF-alpha inhibitor-induced psoriasis is a possible pathophysiologic explanation for this reaction.
authors.affiliation: Department of Dermatology and Skin Science, The Skin Care Centre, 835 West 10th Ave, Vancouver, British Columbia, Canada V5Z 4E8.
authors.forename: Gillian C
authors.initials: GC
authors.lastname: de Gannes
authors.forename: Mehran
authors.initials: M
authors.lastname: Ghoreishi
authors.forename: Janet
authors.initials: J
authors.lastname: Pope
authors.forename: Anthony
authors.initials: A
authors.lastname: Russell
authors.forename: David
authors.initials: D
authors.lastname: Bell
authors.forename: Stewart
authors.initials: S
authors.lastname: Adams
authors.forename: Kamran
authors.initials: K
authors.lastname: Shojania
authors.forename: Magdalena
authors.initials: M
authors.lastname: Martinka
authors.forename: Jan P
authors.initials: JP
authors.lastname: Dutz
mesh_terms: D000328:Adult; D000368:Aged; D018501:Antirheumatic Agents / Q000009:adverse effects*; D003875:Drug Eruptions / Q000209:etiology* / Q000473:pathology; D005260:Female; D006801:Humans; D008875:Middle Aged; D011565:Psoriasis / Q000139:chemically induced* / Q000473:pathology; D012216:Rheumatic Diseases / Q000188:drug therapy*; D014409:Tumor Necrosis Factor-alpha / Q000037:antagonists & inhibitors*
chemical_list: D018501:Antirheumatic Agents; D014409:Tumor Necrosis Factor-alpha