Psoriatic arthritis is a condition in which the patient suffers from both psoriasis and arthritis. The skin lesions associated with psoriasis usually appear first, although in some cases the arthritis may be present before the skin lesions. In addition to the skin lesions, patients may also experience joint pain, stiffness and swelling.

T-Cells and Psoriatic Arthritis

When T-cells that are supposed to fight bacteria and viruses in the body also fight healthy tissue, psoriasis and arthritis may result. It is not clear why the immune system malfunctions in this way, but immune system problems are what causes psoriatic arthritis.

Family Medical History

Most patients who have psoriatic arthritis have a family member with psoriatic arthritis. Genes may play a role in the development of this disease and some researchers believe they have identified genetic markers that may be indicative of psoriatic arthritis. Having a family member with the disease does not seal one's fate of developing the disease themselves, however. It simply means that they may be more susceptible to the disease. Certain infections may trigger psoriatic arthritis.

Tumor Necrosis Factor (TNF)

High levels of TNF in the joints and in the skin may be associated with psoriatic arthritis. This substances causes inflammation in rheumatoid arthritis and is thought to play a role in psoriatic arthritis as well. To learn more about psoriatic arthritis, patients with the disease or who have a family member who has the disease are encouraged to consult a physician.