What is Psoriatic Arthritis?
In psoriasis the body’s immune system assaults the skin, resulting in red, scaly, and inflamed areas of the skin. The area affected can be isolated to patches of skin or can cover a general and larger part of the skin. Psoriasis often remains unnoticed because of the large surface area of the skin and because redness can be mistaken for a scratch or rash. Since the skin is the body’s largest organ and first line of defense against bacteria from entering the body, it is interesting to understand how a faulty immune system leads to psoriatic arthritis (PsA), a type of arthritis that will develop in an estimated 10%-30% of patients with psoriasis.
Unlike some other types of arthritis, PsA equally affects both males and females, typically with an onset of symptoms between the ages of 20-50. Swelling, pain, and inflammation of the joints occur in this condition, beginning in a few isolated areas, and then rapidly involving more of the body’s joints in more severe forms of PsA.
Although the condition manifests in different ways, there are common patterns of occurrence:
- A milder form of the condition follows an asymmetrical pattern in which no more than a few joints are affected on opposite sides of the body
- The more severe form involves a symmetrical pattern in which more joints are affected in pairs, and affected simultaneously (for example joints of both the thumbs, or the joints of both the ankles)
- The distal pattern occurs in joints at the ends of the fingers.
- The spinal pattern affects the spine and sacroiliac joints (as it does in spondylitis, another type of arthritis)
What Are The Symptoms and Warning Signs of PsA?
PsA starts with stiffness or mild pain in the joints and is sometimes set off after an injury. Pain is felt typically in the morning, when joints are most rigid, and does not always subside throughout the day. The pain often restricts movement, or can be triggered when the joint is active. PsA can cause fatigue as well. Like other forms of arthritis, approximately 40% of patients have a family member afflicted with the disease.
Diagnosis and Treatment of PsA
It is essential to seek treatment early if you have or suspect you may have PsA. This is because once a joint is damaged severely enough, it is past the point of repair. This type of permanent damage is not reserved to severe cases of PsA only. It can occur just as often in milder cases and should not be ignored as simple joint pain. There are often environmental factors, such as a viral infection or a faulty immune response which can initiate or exacerbate PsA.
Similar to other forms of arthritis, PsA is usually treated with NSAIDs and corticosteroids. These medications offer more of an immediate counter-action against inflammation, but do little in long-term management of the disease. Preventing damage to the joints, which is crucial to successfully treating PsA, is better achieved by administering both DMARDs and medications called biologics. With this course of therapy, inflammation is kept in check and prevention of damage to the joints is better accomplished.
Common DMARD therapy involves the use of methotrexate, typically administered orally or via injection once a week. Biologics are immunosuppressant medications which block a protein in the blood that is responsible for increasing pain and inflammation naturally. In PsA, a protein called tumor necrosis factor (TNF) is present in high amounts in the joints and biologics strive to reduce and better control TNF by blocking its action.
Further research is required to determine effective treatments for PsA and is currently underway at research sites including the Canadian Centre for Clinical Trials.
Did You Know?
PsA is not a continuous condition. It is not uncommon to experience remissions (periods of no skin changes or joint pain) followed by flare ups. Because patients may dismiss periodic changes to their skin and joints, PsA may be under-diagnosed.