A case of abatacept associated neutrophilic dermatosis and a review of the literature.

Abatacept is a novel biological agent that dampens the immune response by blocking the co-stimulation of T-cells, thus downregulating T-cell activation. It is currently approved for the treatment of rheumatoid arthritis (RA). The group of novel immunomodulatory agents, referred to as biologics, have now been used extensively, with established safety and side-effect profiles. There are, however, increasing reports of adverse paradoxical reactions, most notably resulting from anti-tumour necrosis factor (TNF) therapy. While cutaneous adverse reactions to abatacept are rare, there are a few reports of such paradoxical reactions. We report a case of an idiosyncratic paradoxical neutrophilic dermatosis associated with the use of abatacept.