VHOSPITAL.CLINIC · Differential Diagnosis
Gout vs Reactive Arthritis
Clinical comparison — shared symptoms, key differences, distinguishing diagnostic tests, treatment pathways, and when to seek urgent evaluation.
Condition Overview
Condition A
Gout
Gout is a form of inflammatory arthritis caused by elevated uric acid levels (hyperuricemia) that form crystals in joints. It causes sudden, severe attacks of pain, swelling, redness, and tenderness, most often in the big toe.
Condition B
Reactive Arthritis
Reactive arthritis is joint inflammation triggered by an infection elsewhere in the body, usually intestines, genitals, or urinary tract. The classic triad includes joint, eye, and urethral inflammation.
Shared Symptoms — Why They're Confused
Both conditions present with 4 overlapping symptoms, making clinical differentiation essential.
Key Clinical Differences
Gout
- Acute monoarthritis — 1st MTP joint (podagra) most common
- Hyperuricaemia on blood tests
- Urate crystals in joint aspirate (needle-shaped, negatively birefringent)
- Triggered by dietary excess, dehydration, diuretics
Reactive Arthritis
- Asymmetric oligoarthritis following GI or genitourinary infection (Chlamydia, Salmonella)
- Triad: urethritis, conjunctivitis, arthritis (Reiter's)
- HLA-B27 positive in 75%
- No urate crystals; may have circinate balanitis
Distinguishing Diagnostic Tests
| Test | Gout | Reactive Arthritis |
|---|---|---|
| Joint aspiration / polarised microscopy | Needle-shaped negatively birefringent urate crystals — diagnostic | No urate crystals; neutrophils; sterile culture |
| Serum uric acid | Elevated (>360 µmol/L in women, >420 in men) | Normal — not a urate disorder |
| Infection history | No preceding infection; dietary/dehydration trigger | Urogenital or GI infection 1–4 weeks before arthritis onset |
Treatment Approaches
Gout
- •NSAIDs or colchicine for acute attack
- •Allopurinol/febuxostat for urate-lowering therapy
Reactive Arthritis
- •NSAIDs for acute arthritis
- •Antibiotics if infection still active
- •Sulfasalazine for persistent joint disease
When Doctors Consider Each Diagnosis
🔵 Consider Gout when:
- →Podagra, hyperuricaemia, urate crystals, dietary trigger
🟢 Consider Reactive Arthritis when:
- →Post-infectious arthritis, triad with urethritis/conjunctivitis, HLA-B27, no crystals
Explore Each Condition in Detail
Related Clinical Pages
Gout
Medical References
Content on this page is informed by evidence-based clinical sources including:
- World Health Organization (WHO)Global health guidance and disease classification
- National Health Service (NHS)UK clinical guidelines and patient information
- National Institute for Health and Care Excellence (NICE)Evidence-based clinical practice guidelines
- Centers for Disease Control and Prevention (CDC)US public health data and clinical recommendations
- PubMed – NCBIPeer-reviewed biomedical literature and clinical studies
- Cochrane LibrarySystematic reviews and meta-analyses in evidence-based medicine
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