What Is Psoriatic Arthritis?

Psoriatic arthritis (PsA) is an inflammatory arthritis that occurs mainly in people with psoriasis. PsA affects around 30 percent of patients with psoriasis and approximately 500,000 Americans. Inflammatory arthritis refers to a condition that causes joint pain, joint swelling, and joint stiffness. PsA is a part of a larger group of arthritis-types called the spondyloarthropathies. These include ankylosing spondylitis, reactive arthritis, inflammatory bowel disease-associated arthritis, and undifferentiated spondyloarthritis.

PsA can also affect the tendons (such as the achilles tendon) particularly at the site where a tendon (or ligament) inserts onto a bone (known as the enthesis). The pattern of joints involved in PsA varies considerably from person to person. Some people may have only one joint involved, some may have 2-3 joints involved, and others may have many joints involved similar to patients with rheumatoid arthritis (RA). Patients with PsA may have arthritis in the sacroiliac joints which can lead to low back or buttock pain or stiffness. The cause of psoriatic arthritis is unknown. It can occur at any age and women and men are affected equally.

Signs and Symptoms of PsA and the spondyloarthropathies include:

  • Fatigue
  • Joint Swelling
  • Joint Pain
  • Joint tenderness
  • Warmth of the joint
  • Stiffness of the joints, neck or back upon awakening in the morning or after prolonged periods of rest or inactivity
  • Swelling, redness and severe pain in an entire finger or toe such that it looks like a sausage ("sausage digit" or dactylitis)
  • Weakness of the arms or legs

Diagnosis of Psoriatic Arthritis

There are no blood tests that can diagnose PsA. The CASPAR (CIASsification of Psoriatic ARthritis) criteria are often used to define psoriatic arthritis in clinical trials. These criteria require that a patient have inflammatory arthritis (swelling in the joint), enthesitis (inflammation where a tendon or ligament inserts onto the bone) or spondylitis (inflammation in the spine) and at least three points from the following:

  • Evidence of current psoriasis (diagnosed by a rheumatologist or dermatologist) or personal history of psoriasis (2 points), OR family history of psoriasis (1 point).
  • Typical psoriatic nail dystrophy (pitting of the nails or breaking a part of the nails) on current physical examination (1 point)
  • Sausage Digit (known as dactylitis) on exam or recorded by a rheumatologist (1 point)
  • Negative rheumatoid factor (1 point)
  • X-ray evidence of new bone formation in the hands or feet (excluding osteophytes, the type of new bone formation found in osteoarthritis) (1 point)

Treatment at Penn

Penn Programs & Services for Psoriatic Arthritis

Psoriatic Arthritis and the Spondyloarthropathies Program

Penn Rheumatology provides advanced diagnosis and treatment for psoriatic arthritis (PsA) and other arthritis-types called the spondyloarthropathies.

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