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Psoriatic arthritis (PsA) is a type of arthritis that causes joint pain, swelling, and stiffness in some people who have psoriasis. Psoriasis is a skin condition that causes flakey patches of skin which form scales. About 30% of people with psoriasis also develop PsA1,2,3.
PsA affects men and women equally. Prevalence of PsA ranges from 0.1% to 1% in the general population around the world4,5.
The clinical presentation of PsA is varied. The earliest classification of PsA by Moll and Wright included five subtypes:
Researchers do not yet fully understand the causes of PsA. However, they believe that the disease develops due to a combination of genetic, immunologic, and environmental factors4,7.
Genetic factors
People with a family history of psoriasis or PsA are more likely to develop the conditions
than those without5.
More than 40% of people with psoriasis or PsA have family members with psoriasis or PsA7.
Immunologic factors
Both psoriasis and PsA are immunologically mediated and are autoimmune diseases, which means the immune system mistakenly attacks healthy tissue4,7.
Environmental triggers
Certain infections (human immunodeficiency virus, streptococcal infection) may also contribute to the development of PsA5,7.
Mechanical/emotional stress
or a physical trauma in genetically predisposed individuals have been identified as risk factors for developing PsA too5,6.
People between the ages of 30–50 years are most likely to develop PsA. However, it may occur at any age3
Patients with PsA present with pain and stiffness in the affected joints. Fatigue is also common3. The clinical features of PsA are described in terms of articular and extra-articular manifestations6:
Doctors diagnose PsA by obtaining the medical history, performing a physical examination, and taking x-rays of the joints to check for inflammation and joint damage. Blood tests or joint fluid tests may be done to rule out other diseases, such as rheumatoid arthritis and gout4 .
Treatment of PsA aims at relieving the symptoms such as joint inflammation and pain and slowing progression of the disease. The main medicines used to treat PsA are non steroidal anti-inflammatory drugs (NSAIDs), disease-modifiying antirheumatic drugs (DMARDs), and biologics1,4,7.
NSAIDs
NSAIDs are generally useful for symptoms of mild PsA6.
DMARDs
Conventional synthetic DMARDs such as methotrexate, or occasionally sulfasalazine, are useful to treat mild to moderate PsA6.
Biologics
Biologics function by inhibiting particular chemicals in the blood from activating the immune system attack on the lining of joints in the body. Severe peripheral arthritis usually receives treatment with biologics, especially tumor necrosis factor (TNF) inhibitors, which are particularly effective in PsA1,6.
Non-pharmacological therapies, including physical therapy, occupational therapy, exercise program, and smoking cessation, should be strongly encouraged and incorporated in the treatment plan6
Pain and mobility
Prognosis of PsA varies from mild joint disease to severe and deforming joint damage. Early treatment of PsA is associated with improved patient-reported outcomes8,9
