The reasons for arthritis are manifold and there is no single factor which causes the onset. Some arthritis subtypes are attributed to infections or to a degenerative process that is a reduction of joint function by abrasion, aging, or false or non-usage of the joint. Others such as rheumatoid arthritis, juvenile idiopathic arthritis, and psoriatic arthritis are chronic autoimmune diseases. This means that at a certain time point the immune system becomes destabilised. Usually the immune system detects foreign invaders such as viruses, bacteria, or fungi and destroys them while the body’s own cells stay untouched. In arthritis, an over-stimulated immune system causes the body to mistakenly attack its own cells. Specific defensive white blood cells, called T-lymphocytes or T cells, migrate into the joint and cause a release of messenger substances which then initiate the inflammation.
The patient suffers from painful joint swelling and resulting limitations of motion. Because these inflammatory rheumatic diseases are systemic conditions they do not only affect joints but impair the whole body. Therefore, other organs such as heart, lungs, liver, eyes, or skin can be affected too.
The actual factors which cause the over-stimulation of the immune system are still poorly understood. People of any age, sex, or race can develop arthritis. However, genetic predispositions may very likely encourage the onsets of diseases like rheumatoid arthritis, juvenile idiopathic arthritis, psoriasis, and psoriatic arthritis . Furthermore, hormones, stress situations, and/or environmental conditions such as infections or smoking habit are thought to have an impact on changes of the immune system.