How can cellulitis be distinguished from gout and what are the appropriate initial management strategies?

Distinguishing Cellulitis from Gout

Cellulitis presents with poorly defined borders, gradual onset, and diffuse erythema, while gout presents with rapid onset of severe pain (often out of proportion to findings), well-localized joint involvement, and can be definitively diagnosed by synovial fluid aspiration showing monosodium urate crystals. 1, 2

Key Clinical Distinguishing Features

Cellulitis Characteristics

• Poorly defined borders with areas of erythema, swelling, tenderness, and warmth spreading across skin and subcutaneous tissue 2
• May show "peau d'orange" appearance due to superficial edema 2
• Lymphangitis and regional lymph node inflammation may be present 2
• Systemic symptoms typically mild (fever, tachycardia) unless severe 2
• Gradual onset over hours to days 3

Gout Characteristics

• Rapid onset of severe pain, erythema, swelling, and warmth in the affected joint 4
• Pain is often out of proportion to physical findings 1
• Well-localized to a specific joint (commonly first metatarsophalangeal joint, but can affect any joint) 1
• Joint-specific involvement rather than diffuse skin changes 1

Diagnostic Approach

For Suspected Gout

Perform synovial fluid aspiration when clinical judgment indicates diagnostic testing is necessary - this is the reference standard for diagnosing acute gout by identifying monosodium urate crystals 1

• Synovial fluid analysis should include: cell count, Gram stain, cultures, AND crystal examination to rule out coexistent septic arthritis 4
• This is critical because gout and septic arthritis can coexist and present similarly 4, 5

For Suspected Cellulitis

• Blood cultures, tissue aspirates, or skin biopsies are NOT required for typical cases 2
• These tests should only be considered for patients with malignancy, severe systemic symptoms, or unusual predisposing factors 2
• Diagnosis is primarily clinical based on history and physical examination 3

Critical Pitfall to Avoid

Gout is frequently mistaken for cellulitis, thrombophlebitis, and septic arthritis due to overlapping symptoms of erythema, warmth, swelling, and pain 4, 6. The key differentiators are:

• Location: Gout is joint-centered; cellulitis spreads diffusely across skin 1, 2
• Border definition: Cellulitis has poorly defined borders; gout has well-defined joint involvement 2
• Onset speed: Gout is rapid (hours); cellulitis is more gradual 4, 3
• Pain severity: Gout pain is often disproportionate to findings 1

Initial Management Strategies

For Cellulitis

• Antibiotics active against streptococci (primary cause): penicillin, amoxicillin, or cephalexin for uncomplicated cases 1, 2
• 5-day course is as effective as 10-day course if clinical improvement is seen at 5 days 2
• Elevation of affected area to promote drainage 2
• Coverage for methicillin-resistant Staphylococcus aureus is generally NOT recommended for non-purulent cellulitis 3

For Gout

• Treatment differs significantly from cellulitis and requires gout-specific therapy (anti-inflammatory agents, colchicine, or corticosteroids) 1
• Antibiotics are not indicated unless concurrent septic arthritis is confirmed 4

When in doubt with severe joint involvement, always aspirate to rule out septic arthritis before assuming either diagnosis, as missing septic arthritis has grave consequences 4, 5