5th June 2025

Diagnosis

Clinical features

Patients often present with symmetrical synovitis of the small joints of the hands and feet, though any joint can be affected. This consists of pain often worse at rest, swelling of the joint, heat and early morning stiffness lasting over 1 hour. Extra-articular changes are often skin-related and can be numerous:

• Atrophic, dry, friable skin
• Raynaud phenomenon 
• Nail changes e.g., onycholysis, nail ridging and splitting, clubbing
• Rheumatoid nodules – only seen in RA
  • solitary or multiple skin-coloured nodules on sites of recurrent pressure or trauma, generally asymptomatic
• Rheumatoid vasculitis – only seen in RA
  • An unusual complication of long-standing severe rheumatoid arthritis involving small to medium-sized vessels
  • Can present as palpable purpura, nailfold infarcts, digital necrosis, ulcers, and urticarial vasculitis
  • A specific manifestation of this vasculitis is a Bywaters lesion – painless purpuric papules of <1mm diameter found on the fingertip or around the nail
• Rheumatoid neutrophilic dermatitis – only seen in RA
  • Rare severe skin manifestation of severe long-standing RA
  • Symmetrical asymptomatic eruption of erythematous papules, nodules, and plaques which may show an annular distribution at the extremities
  • Associated with a disease flare and resolves with treatment

There are three classical deformities seen in RA, though they are no longer commonly seen in presenting patients due to the advent of disease-modifying anti-rheumatic drugs (DMARDs). 

• Swan neck deformity – DIP hyperflexion, PIP hyperextension
• Boutonniere deformity – PIP flexion, DIP hyperextension  Image Source: Wikimedia Commons (2021). Swan Neck Deformation Finger, Licensed under a creative commons licence. Available for free at: https://commons.wikimedia.org/wiki/File:Swan_neck_deformation_finger.jpg (Accessed 19 May 2025).  Image Source: Wikimedia Commons (2013). Boutonniare Deformity, Licensed under a creative commons licence. Available for free at: https://commons.wikimedia.org/wiki/File:Boutonni%C3%A8re_deformity.jpg (Accesed 19th May 2025)
• Ulnar deviation – inflammation of MCP joints causing finger joint dislocation and deviation to the ulnar side Image Source: Wikimedia Commons (2019). Rheumatoid Arthritis – Smart Servier, Licensed under a creative commons licence. Available for free at: https://commons.wikimedia.org/wiki/File:Rheumatoid_arthritis_–_Smart-Servier_(cropped).jpg (Accessed 19 May 2025).

RA is a systemic disease and in more severe forms can be associated with pleuritis, interstitial lung disease, pericarditis, and inflammatory eye disease.