Which feature helps differentiate erysipelas from cellulitis?

• A. Well-Demarcated Border
• B. Pain Out Of Proportion
• C. Lymphangitis Common In Cellulitis
• D. Abscess Formation

Answer: (A)

Erysipelas is an infection of the superficial dermis and lymphatics, so its key visual clue is a clearly defined, sharp, and often raised border that separates the involved skin from normal skin. This well-demarcated edge is what most reliably distinguishes it from cellulitis, which involves deeper dermal and subcutaneous tissues and tends to spread with ill-defined, poorly marginated borders.

In practice, you’ll see erysipelas as a bright red, warm plaque with a crisp edge, often elevated and with rapid onset. Cellulitis usually looks more diffuse and sloppy in its margins, reflecting its deeper tissue involvement. Other clues like severe pain out of proportion can suggest more aggressive processes (e.g., necrotizing infections), and purulent abscesses are less typical of erysipelas and point toward a focal purulent issue within cellulitis. Lymphangitic streaking can occur with either condition and isn’t the defining difference.

So the sharply delineated border is the best feature that helps tell erysipelas apart from cellulitis.