Spondyloarthropathies are a group of related, but phenotypically distinct inflammatory disorders, including ankylosing spondylitis, psoriatic arthritis, reactive arthritis, enteropathic arthritis (also known as irritable bowel disease), and undifferentiated arthritis. One of the main clinical features of each of these conditions is inflammatory low back pain. This 2-part blog discusses the difference between the seronegative spondyloarthropathies and what features are indicative of inflammatory low back pain.