Criteria of Bennett for the Diagnosis of Psoriatic Arthritis

Does the patient have clinically apparent psoriasis affecting skin and/or nails?

Number of joints with pain and soft tissue swelling

Number of joints with limitation in motion

Duration of psoriatic and joint changes

Have the psoriatic and joint changes been observed by a physician?

Is there an inflammatory arthritis affecting a distal interphalangeal joint?

Do distal interphalangeal joints show Heberden's or Bouchard's nodes?

Does the patient have 'sausage'-shaped fingers or toes?

Does the arthritis show an asymmetrical distribution in the hands and feet?

Are subcutaneous nodules present?

Is the serum rheumatoid factor test positive?

Do peripheral radiographs show erosive arthritis affecting small joints with a relative lack of osteoporosis?

Is erosive osteoarthritis seen in the peripheral radiographs?

• an inflammatory cell infiltrate?

• a normal or increased C3 or C4 level?

• evidence of infection?

• monosodium urate crystals?

• calcium pyrophosphate crystals?

• hypertrophy of the synovial lining?

• a predominantly mononuclear cell inflammatory infiltrate?

• granulomas?

• evidence of tumor?

• sacroiliitis?

• syndesmorphytes?

• paravertebral occification?