What is psoriatic arthritis?
Psoriasis is a chronic skin condition which causes whitish and reddish scales over the body (elbows, knees, legs, chest, abdomen, back, scalp etc). Psoriatic arthritis is a typical inflammatory arthritis which occurs in patients with psoriasis. When a patient with characteristic skin features of psoriasis presents with swelling, pain and stiffness in joints, a diagnosis of psoriatic arthritis is considered. In some patients, arthritis may appear before skin lesions. In some, there may be skin lesions of psoriasis with vague aches and pains like pain in heels, feet, around knees, lateral aspect of thighs etc.
Is there a blood test to diagnose psoriatic arthritis?
No. There is no specific blood test to diagnose psoriatic arthritis. However, the rheumatoid factor test (RA factor, as it is commonly called) is usually negative and another test for HLA-B27 may be positive in psoriatic arthritis. The diagnosis of psoriatic arthritis is made based on patient history (including a family history of psoriasis in a relative) and clinical examination with less reliance on blood tests. But, the blood tests are useful to monitor disease activity once treatment is initiated.
Which joints are involved in psoriatic arthtritis?
Psoriatic arthritis can involve almost any joint. Typically, patients tend to have involvement of hand joints and spine (lumbar spine and cervical spine). Usually the joints of one side of the body are involved in psoriatic arthritis though sometimes a symmetric involvement (as seen in rheumatoid arthritis) may also be present.
How is psoriatic arthritis treated?
Treatment involves administration of immunosuppressive medications such as methotrexate. Methotrexate is useful for both skin lesions as well as joint problems. Use of other medications such as non-steroidal anti-inflammatory drugs (NSAIDs) is required as necessary. Newer class of drugs called biologicals (eg. Etanercept, infliximab) may be helpful in severe disease. In addition, local application of ointments and lotions may be continued for treatment of skin lesions.