Peripheral Spondyloarthritis (pSpA)
Peripheral spondyloarthritis (pSpA) is a new-ish name for a subtype of spondyloarthritis (SpA). What was once known as ankylosing spondylitis or spondyloarthritis may now be diagnosed as having peripheral spondyloarthritis or axial spondyloarthritis.1
The name change came about as the result of two classification systems for diagnosing:
- The Traditional SpA Classification System which recognizes six separate diseases within SpA, including ankylosing spondylitis, enteropathic arthritis, psoriatic arthritis, reactive arthritis, undifferentiated spondyloarthritis, and juvenile spondyloarthritis.
- The Newer SpA Classification System (ASAS) with two broad categories, axial and peripheral spondyloarthritis, that doctors feel better explains the full range of SpA.1
Figure 1. The different types of spondyloarthritis
Symptoms of peripheral spondyloarthritis
Peripheral spondyloarthritis (pSpA) tends to cause inflammation in the joints and/or tendons outside the spine or sacroiliac joints, as opposed to axial spondyloarthritis which centers on the spine and sacroiliac joints.
In pSpA, the joints more often impacted are found in the hands, wrists, elbows, shoulders, knees, ankles and feet. Dactylitis, or inflammation of the tendons in the fingers or toes, and enthesitis, or inflammation where the ligaments meet the bones, are both more common than in the axial form of the disease.
Some people only develop the symptoms of peripheral or axial spondyloarthritis, while others develop both.
Interestingly, almost everyone diagnosed with psoriatic arthritis fits the pSpA category at some time in their disease progression. Sometimes people diagnosed with reactive, enteropathic and undifferentiated arthritis also sometimes fit the peripheral pattern.1
Diagnosing peripheral spondyloarthristis
A process of elimination is used to diagnose peripheral spondyloarthritis and distinguish it from other forms of the spondyloarthritis.
First, you should have either arthritis, enthesitis, or dactylitis. In addition, you should also have these symptoms:
- Uveitis, psoriasis, or Crohn's disease/ulcerative colitis, preceding infection, test positive for HLA–B27, or show signs of sacroiliitis (inflammation of the sacroiliac joint on MRI or X-ray.2-3
- Or, have two or more of the following: arthritis, dactylitis, enthesitis, family history of SpA, and history of IBP.2-3
Treatment for peripheral spondyloarthristis
One study shows that early, aggressive treatment of pSpA with biologics (namely golimumab, brand name Simponi) helps keep the early stage of the disease in remission in 50 percent of patients. Methotrexate alone was not successful in keeping patients in remission.4
The effectiveness of this treatment eventually decreases over time and the disease will progress. However, this study showed that early diagnosis can delay joint damage.4