I am not an expert on the arthritis since I am just getting it myself, but Celebrex is what my doc recommended. I too get periods of extremely itchy rashes all over. So far my doc has me take Benadryl until the cycles subside a bit, then a Zyrtec every day after that. A steroid shot might also help. I'm sorry your dad is going through all of this. You'll get some great advice on this site.
34 year old female, Diagnosed 5 years ago
Current Meds: Remicade every 6 weeks, Prednisone 20mg, Prevacid, Sustenex, Lialda, Lexapro (anxiety), Synthroid, Iron, vitamin, Fish Oil
Expecting first child 12/08 via gestational surrogate!!!!