Treatments directed against the proinflammatory cytokine tumour necrosis factor α (TNFα) are effective in rheumatoid arthritis and spondyloarthropathies. In patients with inflammatory arthritis secondary to psoriasis, chronic skin plaques also resolve with this treatment. We report on a series of clinical cases in which, conversely, there was a first presentation of psoriasis while on anti-TNF treatment.

The first case is that of a 49-year-old man with established ankylosing spondylitis, who was started on infliximab and showed an excellent response. After 8 months of treatment, he developed an erythematous, pustular rash over his back (fig 1⇓). No clinical or serological evidence of infection was found and his medication, …