Psoriasis could be a paradoxical reaction to tumor necrosis factor-α antagonist therapy and it has been reported with rituximab therapy. Our objective was to assess the rates of new-onset and flare of preexisting psoriasis in patients taking rituximab for rheumatoid arthritis (RA).
The nationwide multicenter prospective AutoImmunity and Rituximab (AIR) registry was set up in 2006 by the French Society for Rheumatology to collect data on patients taking rituximab for joint diseases. We identified patients with RA in the registry who had psoriasis listed as an adverse drug reaction, and we obtained additional information from their physicians if needed. We computed the incidence rates of new-onset and flare of preexisting psoriasis according to the rituximab exposure time.
Among the 1927 patients in the registry with RA, 2 had new-onset and 5 had flare of preexisting psoriasis after a median followup of 39.2 weeks. Incidence rates were 1.04/1000 person-years (95% CI 0.13 to 3.8) for new-onset psoriasis and 2.6/1000 person-years (95% CI 0.84 to 6.1) for flare of preexisting psoriasis. Rituximab rechallenge in the 2 new-onset cases and in 2 flare cases was not followed by recurrence or exacerbation of psoriasis. Two of the 5 flare cases developed after discontinuation of methotrexate.
Despite the small number of cases observed, leading to wide CI, the incidence rates in our study do not support a causative role of rituximab therapy in new-onset or flare of preexisting psoriasis in patients with RA.