Onset of palmoplantar pustular psoriasis while on adalimumab for psoriatic arthritis: A ‘class effect’ of TNF-α antagonists or simply an anti-psoriatic treatment adverse reaction?

Abstract

Adalimumab is a human, recombinant IgG1 monoclonal antibody that specifically blocks the interaction of tumour necrosis factor (TNF)-α with the p55 and the p75 TNF-α cell surface receptors. We report the appearance of palmoplantar pustular psoriasis in a patient after 6 months of successful adalimumab administration for psoriatic arthritis. The development or worsening of psoriatic skin lesions is a known side effect of adalimumab and other TNF-α antagonists increasingly reported in the literature. Although it has been reported as a ‘class-effect’ of TNF-α antagonists, we believe that the deterioration or new onset of psoriasis is an adverse reaction seen mainly with drugs used for the treatment of psoriasis and not solely with anti-TNF agents. The latter is probably implying an existing gap in the understanding of the pathophysiology of psoriasis or of the anti-psoriatic drugs’ mechanisms of action.