Table 1

Clinical, serological and radiographic characteristics of PsA and RA

CharacteristicPsARA
Clinical
 Psoriasis+++
 Symmetric joint involvement++++
 Asymmetric joint involvement+++
 Polyarthritis+++++
 Oligoarthritis/monarthritis++
 Distal interphalangeal joint involvement+++
 Metacarpophalangeal and wrist involvement++++++
 Metatarsophalangeal joint involvement++++++
 Axial spine involvement+++
 Cervical spine involvement++++
 Enthesitis+++
 Dactylitis++++
 Synovitis+++++
 Tenosynovitis+++++
 Nail dystrophy+++
 Arthritis mutilans+
 Interstitial lung disease++
Serological
 Rheumatoid factor+++
 Cyclic citrullinated peptide antibodies−*+++
 C reactive protein+++++
 Erythrocyte sedimentation rate+++++
 Th17 cell upregulation++
 TNF-α-driven++++++
 IL-17A-driven+++
 IL-12/23-driven+++
 IL-6-driven+++
Imaging
 Pencil-in-cup deformity++
 Ankylosis++
 Subluxation++++
 Bone proliferation+++
 Number of erosions++++
 Bone erosion++++
 Synovitis+++++
 Tenosynovitis+++++
 Distal interphalangeal joint involvement+++
Genetic
 HLA-B27 alleles++
 HLA-DRB1 alleles++
  • The greater number of symbols (+, ++, +++) indicates a more common characteristic. The dash (–) indicates the characteristic is not common.

  • *Approximately 5% of patients with PsA have seropositive findings for anticyclic citrullinated peptide antibodies.71

  • HLA, human leucocyte antigen; IL, interleukin; PsA, psoriatic arthritis; RA, rheumatoid arthritis; Th17, T helper 17; TNF, tumournecrosis factor.