Psoriatic Arthritis
What causes it?
The cause of psoriatic arthritis is not yet known. It is believed that hereditary factors, abnormalities of the body’s immune system and environmental factors play roles in disease development.
It has been found that if one identical twin develops psoriasis, the other twin will also develop it 70 percent of the time. The lack of complete concordance between identical twins suggests a role for environmental factors. It also has been found that if you have a first-degree relative (mother, father, sister, brother) with psoriatic arthritis, you are 50 times more likely to develop the disease than people without an affected family member. Within a family, there may be some members who develop only psoriasis or arthritis and some who develop both conditions.
The environmental factors that have been implicated in psoriatic arthritis are infectious agents (Streptococci and Staphylococci in particular) and physical trauma, but researchers have found no firm evidence to back either of these theories.
