What do rheumatologists want to know about the diagnosis, treatment, and management of Psoriatic Arthritis (PsA)?

What Rheumatologists Want to Know About Psoriatic Arthritis

Rheumatologists need comprehensive knowledge of psoriatic arthritis (PsA) as a heterogeneous, potentially severe disease requiring early diagnosis, thorough assessment of all disease manifestations, and targeted treatment approaches to prevent joint damage and maximize quality of life. 1

Diagnosis and Classification

• PsA diagnosis should follow the CASPAR (Classification Criteria for Psoriatic Arthritis) criteria, focusing on inflammatory features including joint pain, spine/enthesis involvement with erythema, warmth, swelling, and prominent morning stiffness 2
• Diagnosis ideally involves collaboration between rheumatologists and dermatologists, especially when clinically relevant skin involvement is present 1
• Key clinical features to identify include:
  • Peripheral arthritis patterns (asymmetric oligoarthritis or symmetric polyarthritis) 1
  • Distal interphalangeal joint involvement, which can sometimes be the only affected joints 1
  • Dactylitis ("sausage digit") - a combination of enthesitis and synovitis involving an entire digit 2
  • Enthesitis - inflammation at tendon, ligament, or joint capsule insertion sites, commonly at plantar fascia and Achilles tendon 2
  • Nail disease (pitting, onycholysis) occurring in 80-90% of PsA patients 1
  • Axial involvement, which usually occurs together with peripheral arthritis 1

Comprehensive Assessment

• Baseline evaluation should include a thorough assessment of all disease domains: 2, 1

  • Peripheral joint assessment (68 joints for tenderness; 66 joints for swelling)
  • Pain (patient-reported on visual analogue or category rating scale)
  • Patient global assessment of disease activity
  • Physical function (using Health Assessment Questionnaire - HAQ)
  • Health-related quality of life (using SF-36 or PsA-specific PsAQoL)
  • Fatigue (patient self-report or instruments like FACIT)
  • Laboratory tests including acute phase reactants (CRP, ESR)
  • Radiographic assessment based on clinical manifestations

• Poor prognostic factors that rheumatologists should identify: 1, 2

  • Polyarticular disease (high number of actively inflamed joints)
  • Elevated ESR/CRP
  • Previous treatment failures
  • Existing joint damage (clinical or radiographic)
  • Diminished quality of life

Treatment Approach

• Treatment should aim at reaching remission or minimal/low disease activity through regular monitoring and appropriate therapy adjustment 1

• Treatment decisions should be based on: 1

  • Specific musculoskeletal manifestations present (peripheral arthritis, axial disease, enthesitis, dactylitis)
  • Severity of skin involvement
  • Presence of comorbidities
  • Patient preferences
  • Safety considerations

• Treatment algorithm for peripheral arthritis: 1

  • NSAIDs may be used for symptomatic relief of musculoskeletal signs and symptoms
  • For polyarthritis, conventional synthetic DMARDs (csDMARDs) should be initiated rapidly, with methotrexate preferred in those with relevant skin involvement
  • For monoarthritis or oligoarthritis with poor prognostic factors, csDMARDs should be considered
  • For inadequate response to at least one csDMARD, biologic DMARDs (bDMARDs) should be commenced
  • TNF inhibitors have demonstrated excellent efficacy in resolving both skin and joint disease 3
  • Newer biologics targeting IL-17, IL-23, or JAK inhibitors are effective options for refractory disease 1

• Treatment considerations for specific manifestations: 1

  • For predominant axial disease, NSAIDs followed by biologics (anti-TNF, IL-17 inhibitors) are recommended
  • For enthesitis, NSAIDs, local glucocorticoid injections, or biologics may be used
  • For dactylitis, NSAIDs, local glucocorticoid injections, csDMARDs, or biologics may be used

Monitoring Disease Activity and Treatment Response

• Treatment response for peripheral arthritis can be evaluated using: 1, 2

  • 28-joint Disease Activity Score (DAS28)
  • European League Against Rheumatism (EULAR) response criteria
  • American College of Rheumatology (ACR) percentage response criteria (ACR20/50/70)

• For axial disease, the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) may be used 2

• Inadequate response is defined as failure to demonstrate acceptable clinical improvement despite appropriate therapy duration and dosing 1

Comorbidity Assessment

• Rheumatologists should evaluate and manage important comorbidities: 1, 2
  • Cardiovascular disease risk factors (hypertension, hyperlipidemia, diabetes)
  • Metabolic syndrome components
  • Obesity (which can affect treatment response)
  • Inflammatory bowel disease
  • Depression and anxiety
  • Liver disease (non-alcoholic fatty liver disease)

Multidisciplinary Approach

• Collaboration between rheumatologists and dermatologists is essential when there is clinically relevant skin involvement 1
• The primary goal of treatment is to maximize health-related quality of life through control of symptoms, prevention of structural damage, normalization of function, and social participation 1
• Early identification and treatment of PsA is crucial for improving long-term outcomes and preventing permanent joint damage 1, 4