CASPAR Criteria for Psoriatic Arthritis

CASPAR Criteria for Psoriatic Arthritis
Established Inflammatory Articular Disease (Required)
Current Psoriasis
History of Psoriasis
Family History of Psoriasis
Dactylitis (current or history)
Juxta-Articular New Bone Formation
Rheumatoid Factor Negative
Nail Dystrophy
CASPAR Score: 0
Entry Criterion Not Met
Established inflammatory articular disease (joint, spine, or entheseal) is required.
Provides classification criteria for psoriatic arthritis.

Why Use

Provides a standardized, validated tool to assist in identifying PsA, with high sensitivity (91% in the original study) and specificity (98%). Helps ensure consistent diagnosis in research settings. May aid in the evaluation of patients with suspected PsA in clinical settings.

When to Use

Use in patients with inflammatory arthritis, enthesitis, or spondylitis where psoriatic arthritis (PsA) is a diagnostic consideration.

Formula

A patient must have inflammatory articular disease (joint, spine, or entheseal) with ≥3 points from the following 5 categories: Criteria Points History of psoriasis Personal history or family history of psoriasis in a first- or second-degree relative 1 Current psoriasis: psoriatic skin or scalp disease present today, diagnosed by a rheumatologist or dermatologist 2 Typical psoriatic nail dystrophy (onycholysis, pitting, and hyperkeratosis on exam) 1 Rheumatoid factor negative (any method except latex; ELISA or nephelometry preferred) 1 Current dactylitis (swelling of an entire digit) or history of dactylitis recorded by a rheumatologist 1 Juxtaarticular new bone formation on hand or foot x-ray (ill-defined ossification near joint margins excluding osteophyte formation) 1

Pearls / Pitfalls

Derived from the international Classification of Psoriatic Arthritis (CASPAR) study, which included 588 patients with PsA from 30 clinics across 13 countries, as well as a control group with other forms of inflammatory arthritis. Should not be used in cases that do not demonstrate evidence for inflammatory musculoskeletal disease (e.g., peripheral arthritis, enthesitis, spondylitis). Enables classification of PsA even in the absence of psoriasis, provided other associated features are present.

Advice

These criteria are not a standalone diagnostic tool but can assist clinicians in evaluating and identifying potential PsA cases; their application should always be guided by clinical context and judgment. A potential PsA diagnosis should prompt: Referral to a rheumatologist, if not already involved. Initiation or adjustment of treatment to target inflammation and prevent disease progression (e.g., NSAIDs, DMARDs, biologics). Comprehensive assessment for comorbidities like uveitis, inflammatory bowel disease, and cardiovascular risk factors, which are common in PsA. Regular monitoring of disease activity and adjustment to management plans, as necessary. For patients who do not meet the criteria, consider alternative diagnoses such as rheumatoid arthritis, reactive arthritis, other spondyloarthropathies, osteoarthritis, or crystal arthropathies, and pursue additional workup based on the clinical presentation. Please refer to relevant PsA clinical guidelines, such as those from the American College of Rheumatology , for more detailed recommendations.

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