Skin infections are infectious diseases caused by direct or sexually transmitted invasion of the skin by pathogens, all of which cause local or widespread inflammatory reactions in the skin, and some symptoms are similar and difficult to diagnose by clinical manifestations and signs alone, usually requiring a detailed history and physical examination, of which the pathogenic examination is the gold standard for the diagnosis of the disease. The disease can only be clearly diagnosed if the causative agent is found through pathogenic examination. However, the diagnosis of common viral skin diseases can be confirmed by typical clinical symptoms, signs and history.