Cellulitis vs Erysipelas
How to tell Cellulitis and Erysipelas apart when a board question makes them look alike.
Step 2 CK pairs are in open beta while clinical review finishes. Spot an issue? Tell us.
A sharply demarcated raised border indicates erysipelas rather than diffuse cellulitis.
Side by side
Warm, tender, erythematous skin with poorly defined borders involving deeper dermis and subcutaneous tissue suggests cellulitis.
Raised, bright erythematous plaque with sharply demarcated borders and superficial involvement suggests erysipelas.
Bacterial spread in deeper skin layers causes diffuse soft tissue inflammation.
Superficial dermal lymphatic infection produces abrupt sharply marginated inflammation.
Cellulitis is mainly clinical; ultrasound is useful when abscess is suspected and may show cobblestoning without drainable collection.
Erysipelas often presents with abrupt fever and sharply bordered plaque, usually due to beta-hemolytic streptococci; labs may show leukocytosis but diagnosis is clinical.
The trap
Any red leg is labeled cellulitis and superficial streptococcal erysipelas pattern is missed. Border quality and tissue depth determine targeted therapy and need for abscess evaluation.
The repair move
Next best step: start streptococcal-active antibiotics such as oral cephalexin 500 mg four times daily for uncomplicated erysipelas, or IV cefazolin if systemic toxicity is present. If cellulitis has purulence or abscess concern, perform ultrasound and drain abscess when present, then tailor MRSA coverage as indicated.
Try a free question
CoreA 52-year-old man has lower-leg erythema that is warm, tender, and poorly demarcated without fluctuance. What is the next best step in management?
Show answer and explanation
Answer: A. Treat as nonpurulent cellulitis with appropriate oral antibiotics. Typical nonpurulent cellulitis is treated empirically with streptococcal and MSSA-active oral therapy when stable.
Why the other choices are tempting
- B. Wrong. Clinical pattern is bacterial soft tissue infection, not superficial fungal disease.
- C. Wrong. Routine debridement is unnecessary without necrotizing signs.
- D. Wrong. Afebrile cellulitis still requires treatment.
- E. Wrong. Thrombolytics do not treat skin infection.
Flashcards
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Which visual skin clue most strongly supports erysipelas?
Raised, sharply demarcated erythematous borders.
How does cellulitis border appearance usually differ from erysipelas?
Cellulitis has less distinct, more diffuse margins.
Quick answers
What is the fastest way to tell Cellulitis from Erysipelas?
A sharply demarcated raised border indicates erysipelas rather than diffuse cellulitis.
What is the key clue for Cellulitis?
Warm, tender, erythematous skin with poorly defined borders involving deeper dermis and subcutaneous tissue suggests cellulitis.
What is the key clue for Erysipelas?
Raised, bright erythematous plaque with sharply demarcated borders and superficial involvement suggests erysipelas.
What is the common trap with Cellulitis vs Erysipelas?
Any red leg is labeled cellulitis and superficial streptococcal erysipelas pattern is missed. Border quality and tissue depth determine targeted therapy and need for abscess evaluation.