What is erysipelas primarily caused by?

Erysipelas is primarily caused by infection with Streptococcus pyogenes, also known as Group A Streptococcus (GAS). This bacterium is responsible for various skin and soft tissue infections, and erysipelas is characterized by its distinct clinical features, including a raised, well-demarcated, erythematous rash, often accompanied by fever and systemic symptoms. The diagnosis is typically supported by the sudden onset of these symptoms, and the lesions are usually found on the face and lower extremities.

This bacterium invades the dermis and subcutaneous tissues, leading to the inflammation and characteristic appearance associated with the condition. The identification of GAS as the primary causative agent is crucial, as it informs both the clinical understanding of the disease and the selection of appropriate antibiotic therapy for effective treatment. Other types of infections, such as fungal or viral, do not present the same clinical picture as erysipelas and are managed using entirely different therapeutic approaches. Furthermore, while insect bites can lead to localized infections, they are not the primary cause of erysipelas.