Undifferentiated spondyloarthritis (USpA) is reportedly the most difficult disease to diagnose in the spondylitis family and consequently eludes a correct diagnosis in many patients who have it. USpA is the least well known of the group and is still unrecognized by some physicians. Sometimes a doctor may make an initial diagnosis of “spondyloarthritis” or “unclassified seronegative spondyloarthritis” if certain symptoms are present, but are not enough to make a specific diagnosis. Sadly, people with USpA may initially hear that they are “anxious and depressed” or receive a diagnosis of fibromyalgia, which is a chronic disorder associated with widespread muscle and soft tissue pain.
A person with USpA may have signs and symptoms of spondylitis that do not quite fit into a specific category. For example, someone may have (or have experienced) iritis and heel pain, as well as being HLA-B27 positive, but initially not have the SI joint or spinal involvement associated with ankylosing spondylitis.
A rheumatologist is commonly the type of physician who will diagnose USpA, since they are doctors who are specially trained in diagnosing and treating disorders that affect the joints, muscles, tendons, ligaments, connective tissue, and bones. A diagnosis of USpA normally comes after a physical exam, laboratory tests, and X-rays.