A 52-year-old woman presents with possible spondylitis including sacroiliitis, which she reports has been developing over the course of 3 or 4 months. She has been experiencing stiffness and pain, however, for about a year, particularly in the morning. The distribution of musculoskeletal symptoms is monoarticular and asymmetric. Mild dactylitis is also seen. The scalp has mild lesions, which the patient says are not bothersome.