Erysipelas is a “common but potentially serious bacterial skin infection” that needs quick medical attention, even though it usually responds well to antibiotics. It affects the upper skin layers and lymphatic system, most often caused by group A Streptococcus—the same bacteria behind strep throat. What sets it apart is its appearance: a “bright red, swollen area with sharply defined, slightly raised edges,” making it easy to distinguish from similar infections.

It usually appears on the lower legs but can also affect the face, especially the cheeks and nose. Facial cases may spread faster and cause noticeable swelling in a short time. Symptoms develop suddenly, including redness, warmth, swelling, and tenderness, often with a rash that has clear borders. Many people also experience fever, chills, and fatigue along with the skin changes.

The infection begins when bacteria enter through even the smallest break in the skin. Cuts, insect bites, surgical wounds, eczema, or athlete’s foot can all allow bacteria in. Once inside, they spread through lymphatic vessels, leading to rapid inflammation and visible symptoms.

Certain factors increase the risk, including lymphedema, diabetes, obesity, weakened immunity, chronic skin conditions, and previous infections. Recurring cases are often linked to underlying problems with skin health or circulation, making prevention and management important.

Diagnosis is usually based on appearance and symptoms. Treatment involves antibiotics—oral or intravenous depending on severity—along with rest, hydration, pain relief, and sometimes elevating the affected area. Most people improve within days, but finishing treatment is essential, as untreated cases can lead to complications like “deeper tissue infection, bloodstream infection,” or repeated episodes over time.