Psoriatic arthritis can develop at any time. On average, it appears about 10 years after the first signs of psoriasis. For most people it appears between the ages of 30 and 50. It affects men and women equally. In about one of seven people with psoriatic arthritis, arthritis symptoms occur before any skin lesions.
Like rheumatoid arthritis, psoriatic arthritis is thought to be caused by a malfunctioning immune system. Psoriatic arthritis is usually milder than rheumatoid arthritis, but some patients with psoriatic arthritis have as severe a disease as patients with rheumatoid arthritis.
Psoriatic arthritis can start slowly with mild symptoms, or it can develop quickly. It is very important to have as early and accurate a diagnosis as possible. Left untreated, psoriatic arthritis can be a progressively disabling disease. In fact, half of those with psoriatic arthritis already have bone loss by the time the disease is diagnosed.
It is important for people who seem to be developing severe psoriatic arthritis to begin appropriate treatment. Early treatment can help slow the disease, and preserve function and range of motion. Some early indicators of severe disease include onset at a young age, spinal involvement and the results of certain blood studies.