Ankylosing spondylitis and rheumatoid arthritis difference

In the past nearly 100 years of time, has been the ankylosing spondylitis and rheumatoid arthritis as a disease. Since the 1940s found that serum rheumatoid factor and 1970s found that HLA-B27 and ankylosing spondylitis closely related, ankylosing spondylitis can be from rheumatoid arthritis distinguish. Is now clear and recognized, ankylosing spondylitis and rheumatoid arthritis are two different independent disease, the main difference between their points are: (1) ankylosing spondylitis male multiple women and the majority of rheumatoid arthritis. (2) ankylosing spondylitis, without exception, have sacroiliac joint involvement, rheumatoid arthritis is not. (3) ankylosing spondylitis for the whole spine to the bottom-up involvement, such as rheumatoid arthritis spinal involvement, only violations of cervical spine. (4) peripheral joint disease in ankylosing spondylitis for a few joints, non-symmetry, and the joint mainly to lower extremities, and rheumatoid arthritis for more joints, symmetry, size of limbs, joints may be involved. (5) ankylosing spondylitis with rheumatoid arthritis seen rheumatoid nodules. (6) ankylosing spondylitis all serum rheumatoid factor negative (not higher than the normal population, the positive rate), rheumatoid arthritis and rheumatoid factor positive rate of 60-90%. (7) ankylosing spondylitis to most of HLA-B27 positive, and rheumatoid arthritis for HLA-DR4 positive.