The cause of RA is not yet understood however there does seem to be a genetic factor involved.
The joints in your body
it has athritis
Joint pain is not always and indication of athritis. It can be a symptom to alert you that you may have athritis but is not a guarantee.
Rheumatoid arthritis is an autoimmune disease that effects the joints of the body and other parts of the body with connective tissue What happens is the umune system mistakenly rejects the body's tissue leading to damage.
The imune system
My guess is that you read the term for seronagative Rheumatoid arthritis. Rheumatoid arthritis is a immune disorder that usually exhibits itself in several joints of the body at the same time, (often the same joints on opposite sides of the body). When it is suspected that Rheumatoid arthritis is the culprit one of the blood tests that is done is one for Rheumatoid factor (RF) most of the people that have RA also have a high RF, However in about 20% of cases there is no RF and this is Known as seronegative Rheumatoid arthritis.
athritis
They can do. Rheumatoid arthritis can effect all the joints in the body and one of the peculiarity of it is that often it will effect the opposing joint in the body at the same time.
Yes Rheumatoid arthritis is an immune system disorder in which the immune system turns on the body and mistakenly destroys tissue.
No . Rheumatoid arthritis, (RA) is not infectious) The exact cause of RA is not known aside from it being a immune disorder. Where the body's immune system attacks tissue of the body mistakenly. there seems to be a genetic connection and women with the condition outnumber men 3 to1.
Crohn's Disease, Ulcerative Colitis, Sarcoidosis, Ankylosing Spondylitis, Behcet's Disease, asthma has an autoimmune component, myasthenia gravis, and immune-mediated thrombocytopenia purpura to name a few.
Rheumatoid arthritis nodules can appear any where on your body however I have not been able to find reference to the palm of the hand.