A skin infection, typically caused by an acute streptococcal infection (typically Streptococcus pyogenes), characterized by hot skin, fever, infected dermis and lymphatics, and when the infection reaches deeper tissues, can lead to serious complications. Erysipelas can often lead to dissection of the dermis from the epidermis. Basically the skin gets removed from its base and forms a bubble. Erysipelas can also be present at the onset of gangrene.
The skin also takes on a peau-de-orange appearance where the infection has spread - it looks like the skin of an orange peel in texture.
[Illustration from A Manual of Pathology. Joseph Coats & Lewis K. Sutherland, 1900.]
In our age of antibiotics and prophylactics and cleanliness, it’s very rare that erysipelas leads to severe complications, but it was a very dangerous condition to acquire in centuries past.