Last edited 12/2020 and last reviewed 01/2021

In Summary:

Spondyloarthritis is a group of inflammatory conditions that have a range of manifestations. Spondyloarthritis may be predominantly:

    • axial:
      • radiographic axial spondyloarthritis (ankylosing spondylitis)
      • non-radiographic axial spondyloarthritis
  • or
    • peripheral:
      • psoriatic arthritis
      • reactive arthritis
      • enteropathic spondyloarthritis

People with predominantly axial spondyloarthritis may have additional peripheral symptoms, and vice versa.

In detail:

Spondyloarthritis encompasses a group of inflammatory conditions with some shared features, including extra-articular manifestations

  • both peripheral and axial joints can be affected
  • spondyloarthritides are distinct from rheumatoid arthritis but are as important to recognise and manage early in their presentation to improve health outcomes

Most people with these conditions have either psoriatic arthritis or axial spondyloarthritis, which includes ankylosing spondylitis

  • ankylosing spondylitis and non-radiographic axial spondyloarthritis primarily affect the spine, in particular the sacroiliac joint
  • both conditions present in similar ways; the primary classification difference is whether sacroiliitis is detectable on X-ray.

Psoriatic arthritis may manifest in a number of different patterns

  • include predominant involvement of small joints in the hands and feet, predominant large joint involvement, particularly in the knees, or combinations of these
  • psoriatic arthritis may also involve the axial joints, and inflammation of the entheses and/or finger and toe joints
  • skin and nail involvement may not be present at diagnosis and in its absence, a family history of psoriasis is required to meet the diagnostic criteria.

  • Less common subgroups are enteropathic spondyloarthritis, which is associated with inflammatory bowel disease (Crohn's disease and ulcerative colitis), and reactive arthritis, which can occur in people after gastrointestinal or genitourinary infections.

The final subgroup is people who have undifferentiated spondyloarthritis

  • people generally have an asymmetrical oligoarticular (fewer than 5 involved joints) arthritis, often involving the knees
  • do not meet the diagnostic criteria of the other subgroups at presentation but their disease may evolve to do so at a later stage.

Axial presentations of spondyloarthritis are often misdiagnosed as mechanical low back pain, leading to delays in access to effective treatments. Peripheral presentations are often seen as unrelated joint or tendon problems, and can be misdiagnosed because problems can move around between joints (1).

Seronegative spondarthritis describes conditions, usually associated with seronegative polyarthritis, i.e. without serum rheumatoid factors, which may show changes in the sacroiliac and vertebral joints and ligaments that are indistinguishable from ankylosing spondylitis.

This group includes:

  • psoriatic arthritis
  • Reiter's disease
  • arthritis that accompanies inflammatory bowel disease
  • ankylosing spondylitis
  • Behcet's syndrome
  • Whipple's disease

This group of diseases share various characteristics:

  • all are associated with HLA-B27
  • the characteristic sacroiliitis and spondylitis occur in all of them
  • there is a familial aggregation
  • there is overlap between the different conditions, i.e. it is likely that more than one of these conditions may be present in the same family
  • negative rheumatoid factor tests

Recognition and referral in non-specialist care settings:

  • Do not rule out the possibility that a person has spondyloarthritis solely on the presence or absence of any individual sign, symptom or test result (1)