A 60-year-old woman was diagnosed with psoriasis vulgaris in 2007. Although she received antiallergic drug and ointment at the clinic, her skin condition did not improve, so administration of etretinate was started at the Department of Dermatology in 2009. While skin disease improved a little with etretinate, she still had multiple tender joints including knees, elbows and interphalangeal joints in 2010. She came to Department of Rheumatology in 2011. We diagnosed psoriatic arthritis（PsA）. It was difficult to treat with biologics due to economic problems, and we first treated with salazosulfapyridine（SASP）and prednisolone（PSL）. In spite of the treatment, joint space narrowing of the hip became aggravated, so we switched to infliximab（IFX）from January 2016. We started combined use of methotrexate（MTX） from January 2017, but discontinued due to leukopenia in 3 months. As right hip joint destruction progressed regardless of the treatment, we planned to perform total hip arthroplasty.

  While the main symptoms of PsA are psoriasis, peripheral arthritis, spinal lesions, enthesitis and dactylitis, joint destruction of large joints such as the hip is rare. Hip lesion was reported to occur within 1 year after the onset of PsA and was difficult to stop worsening in spite of the use of biologics. In addition, outcomes after THA would be poor, so we should carefully observe and start appropriate therapies at the appropriate time.