Peripheral Arthritis: Definition and Classification
Peripheral arthritis is an inflammatory joint condition affecting limb joints, characterized by pain, swelling, and stiffness, which can be classified into different types based on the pattern of joint involvement, duration, and relationship to underlying conditions. 1
Types of Peripheral Arthritis
Type 1 Peripheral Arthritis
- Affects fewer than 5 joints (pauciarticular)
- Predominantly affects large weight-bearing joints of the lower limbs
- Asymmetrical distribution
- Acute and self-limiting (less than 10 weeks)
- Does not cause permanent joint damage
- Symptoms correlate with underlying inflammatory bowel disease (IBD) flares 1, 2
Type 2 Peripheral Arthritis
- Affects more than 5 joints (polyarticular)
- Predominantly affects upper limbs
- Symmetrical distribution
- Persistent symptoms lasting months or years
- Independent of IBD activity
- Can lead to more persistent problems 1, 2
Clinical Features and Diagnosis
Diagnosis of peripheral arthritis is primarily clinical, based on:
- Joint pain with evidence of swelling or effusion
- Pattern of joint involvement (pauciarticular vs. polyarticular)
- Relationship to underlying conditions (e.g., IBD, psoriasis)
- Morning stiffness (>30 minutes suggests inflammatory arthritis) 1
- Absence of deformity on imaging (distinguishing from rheumatoid arthritis) 1
Key diagnostic features include:
- Non-erosive nature on radiographs (unlike rheumatoid arthritis)
- Absence of specific laboratory markers (diagnosis by exclusion)
- Consideration of all possible causes (autoimmune, infectious, malignancy, metabolic, etc.) 1
Associated Conditions
Peripheral arthritis commonly occurs in association with:
- Inflammatory bowel disease (prevalence 5-20%)
- Psoriatic arthritis
- Ankylosing spondylitis (32% of patients develop peripheral arthritis) 3
- Reactive arthritis
- Undifferentiated spondyloarthritis
Diagnostic Workup
The following investigations should be considered:
- ESR and CRP (baseline and when clinically relevant) 1
- RF and/or ACPA testing (to rule out rheumatoid arthritis) 1
- X-rays of affected joints at baseline 1
- HLA-B27 testing in specific clinical settings (e.g., suspected axial involvement) 1, 2
Management Approach
Treatment depends on the type of peripheral arthritis:
For Type 1 (Acute, Pauciarticular)
- Treatment of underlying condition (e.g., IBD)
- Rest and physiotherapy
- Simple analgesia
- Short-term NSAIDs (e.g., naproxen) 2, 4
- Local steroid injections for persistent symptoms 2
For Type 2 (Persistent, Polyarticular)
- Rheumatology referral
- NSAIDs or systemic corticosteroids
- Disease-modifying antirheumatic drugs (DMARDs):
Monitoring and Prognosis
- The prognosis of peripheral arthritis is generally good, with most cases not becoming chronic or erosive 1
- Regular monitoring of disease activity is recommended 1
- Women with ankylosing spondylitis have a higher prevalence of peripheral arthritis with greater impact on physical function 7
Important Considerations
- Peripheral arthritis in spondyloarthritis is often neglected in research and lacks specific treatment recommendations outside of psoriatic arthritis 8
- Synovial biopsy is not routinely recommended but may provide diagnostic information in persistent monoarthritis 1
- Predictors of persistent inflammatory arthritis include disease duration ≥6 weeks, morning stiffness >30 minutes, functional impairment, involvement of small joints, involvement of ≥3 joints, and presence of radiographic erosions 1
Peripheral arthritis requires careful assessment to distinguish it from other joint conditions and appropriate management based on the pattern of involvement and associated conditions.