This result is consistent with the clinical assessment of psoriatic arthritis being more an inflammatory condition than neuropathic [13] and the patient's responsiveness to the COX-2i is in agreement with animal studies showing that COX-2 expression and responsiveness to COX-2i seems specific to inflammatory rather than neuropathic pain conditions [14,24], but of course this notion remains to be demonstrated in a population of psoriatic arthritis patients. This evidence concerns the gene PTGS2 and psoriatic arthritis.