Pus moss is a secretion produced by white blood cells after phagocytosis of viral bacteria attached to the surface of ulcers or tissues as necrotic tissue. Pus moss not only affects the patient’s appearance, but can have very serious consequences if left untreated. Etiology: The white blood cells in the normal body tend to attack the invading bacteria at the infection, confining them to a narrow area, so that the pus head is formed, while the dead white blood cells and the corpse of the bacteria and the necrotic organism tissue form pus around it. The causative organism is mainly coagulase-positive Staphylococcus aureus, followed by Streptococcus b haemolyticus, and a few coagulase-negative Staphylococcus albus. Staphylococcal and streptococcal mixed infections are not uncommon. Bacteria can easily multiply on the skin in certain external environments such as high temperature, sweating and skin maceration. In pruritic skin diseases such as prickly heat, insect bite dermatitis, and eczema, the barrier of the skin can be destroyed, which can lead to the invasion of pathogenic bacteria and the development of pustules.