Erysipelas

Erysipelas is a bacterial skin infection that involves the superficial dermis and lymphatics, producing a clearly demarcated, raised, red and tender plaque with warmth. It often presents with fever and malaise and tends to occur on the face or legs.

The condition is most commonly caused by beta-hemolytic streptococci, particularly Streptococcus pyogenes. Staphylococcus aureus can be involved when purulence is present or in hospital-associated cases. Preexisting skin breaks, edema, or lymphatic obstruction can predispose to infection.

Clinically, erysipelas presents with an abrupt onset of fever, chills, and malaise, followed by the appearance of a well-defined, raised, erythematous lesion. The border is sharp and distinct. Lymphatic streaking may be observed. Differentiation from cellulitis can be challenging, but erysipelas typically has a more clearly demarcated margin and a raised edge. Moderate to severe disease or unfamiliar cases may require imaging to exclude deeper infection.

Treatment is usually outpatient for non-severe disease. Oral antibiotics effective against streptococci, such as penicillin V, amoxicillin, or cephalexin, are commonly used for 5–10 days. In penicillin allergy, alternatives include macrolides or doxycycline, guided by local resistance patterns. Severe disease, facial involvement, or systemic symptoms warrant hospital admission and intravenous therapy (e.g., penicillin G or cefazolin). Addressing risk factors and preventing recurrence are important.

Prognosis is generally favorable with prompt treatment; fever and systemic symptoms typically improve within 24–48 hours, and skin changes over several days. Recurrence is common. Preventive measures focus on skin barrier care, treating tinea or dermatitis, managing edema, and reducing venous insufficiency.