[Early spondyloarthritis].

The spondyloarthritides (SpA) are often included in the differential diagnosis of early arthritis with or without low back pain. This is namely true for reactive arthritis which occurs as acute or subacute arthritis in association with urogenital or gastrointestinal bacterial infection. Reactive arthritis can result in chronic or relapsing disease. The SpA group also includes ankylosing spondylitis (axial form or with peripheral arthritis), psoriatic arthritis and SpA in association with inflammatory bowel disease. (Early) undifferentiated SpA has now come into the focus of many researchers since more effective and specific therapy has become available for the SpA. Diagnostic algorithms have been developed and evaluated.