Erysipelas

Erysipelas (/ˌɛrəˈsɪpələs/) is a relatively common bacterial infection of the superficial layer of the skin (upper dermis), extending to the superficial lymphatic vessels within the skin, characterized by a raised, well-defined, tender, bright-red rash, typically on the face or legs, but which can occur anywhere on the skin. It is a form of cellulitis and is potentially serious.

Erysipelas is usually caused by the bacterium Streptococcus pyogenes, also known as group A, β-hemolytic streptococci, which enters the body through a break in the skin, such as a scratch or an insect bite. It is more superficial than cellulitis and is typically more raised and demarcated. The term comes from the Greek ἐρυσίπελας (erysípelas), meaning red skin.

In animals, erysipelas is a disease caused by infection with the bacterium Erysipelothrix rhusiopathiae. In animals, it is called diamond skin disease, and occurs especially in pigs. Heart valves and skin are affected. E. rhusiopathiae can also infect humans, but in that case, the infection is known as erysipeloid and is an occupational skin disease.