Psoriatic arthritis (PsA) is a type of joint pains, that affects people who have skin psoriasis — a condition with red, raised skin, with white and silvery flakes. Around 30% of psoriasis patients will develop Psoriatic Arthritis. Most people develop psoriasis first and later develop psoriatic arthritis, but the joint problems can sometimes begin before the skin psoriasis. Psoriatic Arthritis can affect any age group (from children to old age group).

Symptoms-
Joint pain, stiffness and swelling are the main symptoms. It can affect any joint of body. Other common symptoms include painful, sausage-like swelling of your fingers and toes (Dactylitis), heel pain (Enthesitis). Spine involvement causes neck and back pain with early morning stiffness similar to spondyloarthritis (Ankylosing spondylitis). Some patients will develop recurrent painful Red eyes with blurred vision (uveitis/iritis) and Bowel inflammation with repeated episodes of loose stool (IBD- Inflammatory Bowel disease). They are also at higher risk of cardiovascular disease and Non-Alcoholic Fatty liver disease. Arthritis mutilans a complication of PsA leads to destruction of small bones of fingers leading to severe, painful deformities of hand joints. Symptoms can range from mild to severe. In both psoriasis and psoriatic arthritis, disease flares may alternate with periods of remission.

Causes
JPsoriatic arthritis occurs when your body's immune system mistakenly attacks the joint and skin. Genetic and environmental factors play a role. Many people with psoriatic arthritis have a family history of psoriasis or psoriatic arthritis. Physical trauma, viral or bacterial infection — may trigger psoriatic arthritis in people with an inherited tendency.
Risk factors for Psoriatic arthritis include- People who have pitted, deformed psoriatic nails and family history of psoriasis.

Diagnosis
Clinical examination of joints, skin and nails helps in diagnosis. No single test can confirm a diagnosis of psoriatic arthritis. But some tests can rule out other causes of joint pain, such as rheumatoid arthritis or gout. Imaging- x-rays of hands and feet, Ultrasound of joints, MRI of joints or spine Lab test- ESR, CRP, HLA B27, RA factor (to rule out rheumatoid arthritis), joint fluid analysis if needed to rule out other causes.

Treatment
No cure exists for psoriatic arthritis, so treatment mainly focuses on controlling inflammation in your affected joints to prevent joint pain and deformities.

Medications
Drugs used to treat psoriatic arthritis include:

NSAIDs. Nonsteroidal anti-inflammatory drugs (NSAIDs) relieves pain and reduces inflammation. These may be prescribed for short period. Long-term usage leads to side effects like gastritis, liver and kidney damage.
Disease-modifying anti-rheumatic drugs (DMARDs). These drugs slows the progression of psoriatic arthritis and save the joints from permanent damage. Common DMARDs include Methotrexate, Leflunomide, Sulfasalazine and Apremilast. Sometimes Azathioprine and Cyclosporine are also used. Side effects vary but may include liver damage, bone marrow suppression and infections.
Biologic agents. These medications target specific parts of the immune system that trigger inflammation. This newer class of DMARDs includes Adalimumab, Etanercept, Golimumab, Infliximab, Ixekizumab, Secukinumab, Tofacitinib and Ustekinumab. These drugs may increase the risk of infections. Biologic agents can be used alone or combined with DMARDs such as methotrexate.