TNF and psoriatic arthritis: However, TNF has been implicated in EIM development; for example, TNF has been shown to be upregulated in skin biopsies taken from patients with cutaneous EIMs.48 Furthermore, results from a systematic review indicated that adalimumab and infliximab can be effective treatments for musculoskeletal, cutaneous and ocular EIMs.49 In addition to IBD, aberrant TNF signalling underlies many other chronic inflammatory conditions, including psoriasis, psoriatic arthritis, juvenile idiopathic arthritis, rheumatoid arthritis and ankylosing spondylitis.50,51