Rheumatoid arthritis vs Systemic lupus erythematosus
How to tell Rheumatoid arthritis and Systemic lupus erythematosus apart when a board question makes them look alike.
RA is erosive joint-centered synovitis; SLE is multisystem immune-complex disease with nonerosive arthritis and organ involvement.
Side by side
RA causes chronic symmetric erosive inflammatory arthritis, especially MCP/PIP joints, with anti-CCP, RF, pannus, nodules, and joint deformity.
SLE causes multisystem autoimmune disease with malar/photosensitive rash, oral ulcers, serositis, nephritis, cytopenias, neurologic disease, and nonerosive arthritis.
RA is synovial autoimmune inflammation with pannus-mediated cartilage and bone destruction.
SLE is immune-complex disease with loss of tolerance to nuclear antigens and complement-consuming inflammation.
Anti-CCP specificity, RF, erosions, and synovitis support RA.
ANA, anti-dsDNA, anti-Smith, low complement, proteinuria, cytopenias, and immune complex findings support SLE.
The trap
Both can have inflammatory arthritis and positive autoantibodies, so erosions versus systemic organ pattern separate them.
Watch it explained
The repair move
For autoimmune arthritis, check whether the disease is joint-destructive or multisystem immune-complex driven.
Try a free question
CoreA 38-year-old woman has 5 months of symmetric MCP and PIP arthritis with 90 minutes of morning stiffness, plus hand x-rays showing marginal erosions. Labs: anti-CCP positive at 280 U/mL, RF positive, ESR 58 mm/hr, ANA positive at 1:80 (low titer), anti-dsDNA negative, complement C3 and C4 normal. There is no rash, oral ulcers, or proteinuria. Which diagnosis is most likely?
Show answer and explanation
Answer: A. Rheumatoid arthritis. RA is distinguished by erosive symmetric MCP/PIP synovitis with very high anti-CCP titers and elevated inflammatory markers; low-titer ANA is nonspecific and does not equate to SLE.
Why the other choices are tempting
- B. SLE requires multisystem involvement (rash, oral ulcers, nephritis, cytopenias, serositis) with anti-dsDNA or anti-Smith positivity and low complement, none of which are present.
- C. Psoriatic arthritis requires psoriasis or nail pitting and has DIP/dactylitis.
- D. MCTD has anti-U1 RNP positivity and overlap features (Raynaud, swollen hands).
- E. Sjögren syndrome has dry eyes/dry mouth with anti-SSA/SSB and lymphocytic salivary gland infiltrates.
Flashcards
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What antibody is specific for RA?
Anti-CCP is relatively specific for rheumatoid arthritis.
What antibody tracks lupus nephritis activity?
Anti-dsDNA can track lupus nephritis activity.
Quick answers
What is the fastest way to tell Rheumatoid arthritis from Systemic lupus erythematosus?
RA is erosive joint-centered synovitis; SLE is multisystem immune-complex disease with nonerosive arthritis and organ involvement.
What is the key clue for Rheumatoid arthritis?
RA causes chronic symmetric erosive inflammatory arthritis, especially MCP/PIP joints, with anti-CCP, RF, pannus, nodules, and joint deformity.
What is the key clue for Systemic lupus erythematosus?
SLE causes multisystem autoimmune disease with malar/photosensitive rash, oral ulcers, serositis, nephritis, cytopenias, neurologic disease, and nonerosive arthritis.
What is the common trap with Rheumatoid arthritis vs Systemic lupus erythematosus?
Both can have inflammatory arthritis and positive autoantibodies, so erosions versus systemic organ pattern separate them.