Table 2

 Potential aetiologies for psoriasiform lesions in patients receiving anti-tumour necrosis factor treatment

AS, ankylosing spondylitis; IFN, interferon; PsA, psoriatic arthritis; RA, rheumatoid arthritis; TNF, tumour necrosis factor.
Underlying disease was PsA, not RA or AS
Systemic infection
    Reactive arthritis
    Drug-induced lupus
Adverse drug eruption
    Acute generalised exanthematous pustulosis
    Interstitial granulomatous dermatitis
Adverse drug reaction leading to altered immune response
    Inflammation mediated by unopposed IFNα
    Inflammation triggered by suppression of TNF in eccrine glands
    Suppression of T regulatory cell function