There are two infectious diseases of the skin and the keratin-rich nails that are relevant to lymphology: A major one in the mostly streptococcal-induced erysipelas and a rather minor one in mycosis. We start with two contributions on erysipelas: First with the dermatologist’s perspective, then follows the view of the internal medicine infectious disease specialist, who naturally focuses on severe clinical courses and variants and generally on systemic antibiotic therapy. The streptococcal-induced infectious disease erysipelas has three pathogenetic factors: disruption of the epidermal skin barrier, disruption of blood circulation and lymphovascular drainage, and the disruption of local and general immune status. Erysipelas often arises from complete health within a few hours. Erysipelas usually begins very suddenly (“peracute”) with chills, high fever, which can rise to a temperature of 41 °C, malaise, and even vomiting. The patient is very sick. Therapeutically, systemic antibiotic therapy for at least 10 days, fever reduction, pain management, and decongestion under antibiotic treatment are immediately indicated.