Tocilizumab-induced psoriasiform rash in rheumatoid arthritis.

Tocilizumab (TCZ) is a humanized monoclonal antibody against the interleukin-6 (IL-6) receptor and has been approved for the treatment of rheumatoid arthritis (RA) patients who have had an inadequate response to previous biological therapies. Psoriasiform skin lesions, especially palmoplantar pustulosis lesions, are well described following anti-tumour necrosis factor therapy. We describe a 79-year-old woman with rheumatoid factor-positive, anti-citrullinated protein antibody-positive erosive RA, who developed a psoriasiform palmoplantar pustulosis reaction following treatment with TCZ therapy (IL-6 receptor). The rash showed histological features compatible with psoriasis and disappeared following discontinuation of TCZ.