The most common cause of skin infections are Staphylococcus and Streptococcus. With less common pathogens you can get in contact with the hospital or a nursing home, gardening and swimming in a pond, lake or the sea.
Viral infections are a common skin disease. Basically, only 3 virus groups are able to infect the skin:
Common fungal infections of the skin are caused by yeasts (especially Candida) or dermatophytes. Many such fungi live exclusively in the horny layer of the epidermis (stratum corneum) and do not penetrate deeper into the skin. Extensive infections occur especially in immunosuppression. The latter patients are also more prone to mold infections.