Sero-negative Inflammatory arthritis of the below 40 age group, affecting the spine and the large peripheral joints and with a striking association with HLA-B27.

• Arthropathies characterised by predominant axial skeletal involvement, sacroileitis, asymmetrical oligoarthritis especially of lower limbs, familial clustering, negative Rheumatoid factor, most importantly association with HLA 827 (present in most cases).
• The main ones in the group are Ankylosing Spondylitis, (detailed as separate unit) Psoariatic arthritis, Reiter’s syndrome (conjunctivitis, urethritis orcervicitis in addition), Arthritis of Inflammatory bowel disease (IBD), Anterior Uveitis, and certain juvenile polyarthritis. Reiter’s arthritis also called Reactive arthritis (Post dysenteric OR Post sexually transmitted nonspecific urethritis).
• ESR is always raised, C reactive protein often raised