Psoriatic Arthritis - Diagnosis

Diagnosis

See also: List of human leukocyte antigen alleles associated with cutaneous conditions

There is no definitive test to diagnose psoriatic arthritis. Symptoms of psoriatic arthritis may closely resemble other diseases, including rheumatoid arthritis. A rheumatologist (a doctor specializing in diseases affecting the joints) may use physical examinations, health history, blood tests and x-rays to accurately diagnose psoriatic arthritis.

Factors that contribute to a diagnosis of psoriatic arthritis include:

• Psoriasis in the patient, or a family history of psoriasis or psoriatic arthritis.
• A negative test result for Rheumatoid factor, a blood factor associated with rheumatoid arthritis.
• Arthritis symptoms in the distal Interphalangeal articulations of hand (the joints closest to the tips of the fingers). This is not typical of rheumatoid arthritis.
• Ridging or pitting of fingernails or toenails (onycholysis), which is associated with psoriasis and psoriatic arthritis.
• Radiologic images indicating joint change.

Other symptoms that are more typical of psoriatic arthritis than other forms of arthritis include inflammation in the Achilles tendon (at the back of the heel) or the Plantar fascia (bottom of the feet), and dactylitis (sausage-like swelling of the fingers or toes).