The proximal side of the nail (nail root) is closely attached to the skin, which extends along both sides of the nail toward the distal end, forming a nail groove. Nail fungus is an infection of the nail groove or its surrounding tissue. It is mostly caused by injuries such as tiny puncture wounds, contusions, barbs (reverse stripping) or nail clippings that are too deep, and the causative agent is mostly Staphylococcus aureus. Nail infections are most often seen in adolescents or women. It can generally occur in the fingers or toes, and is often caused by a bad habit of chewing on the fingers if it occurs in the fingers, or by secondary infection of the ingrown nail if it occurs in the toes. The nail infection starts with mild pain and redness on one side of the nail, and then becomes more aggressive and pus spreads to the other side or under the nail, forming an abscess under the nail, where yellowish-white pus can be seen, separating the deep nail from the nail bed. On the side of the ingrown nail of the toe there is often chronic hyperplasia of the sarcoid tissue that keeps the wound from healing for a long time. Acute onychomycosis is mostly caused by staphylococcal infection. This bacterium is present on the human skin and is usually only contaminated and does not become infected, because the body has local and systemic defenses. Only when the body’s defenses are lowered, the integrity of the skin around the nail is destroyed, or the number and virulence of the pathogenic bacteria are too high, does the infection occur. Chronic nail infections are caused by Pseudomonas aeruginosa, fungi (Candida, Aspergillus, etc.) and common Aspergillus due to frequent moisture and impregnation. Inadequate treatment results in the formation of a sub nail abscess, which can also develop into chronic nail infection and chronic osteomyelitis of the finger bones, with chronic sinus tracts and granulation tissue protruding outward from the sinus opening. If the nail abscess is not treated in time, the abscess spreads under the nail and infection occurs between the nail plate and the nail matrix. The skin is swollen and painful around the nail, and yellowish-white pus can be seen under the nail. Some patients will have systemic symptoms such as low fever and elevated white blood cells. 2, purulent dactylitis Nail infection aggravates, the infection spreads to the end skin of the finger, making the finger swollen and tingling. Preventive care: 1. Take care of the skin around the nail, do not damage it, do not cut the nail too short, and do not use your hands to pull the “barbs”. 2, prevention is better than cure. Wooden thorns, bamboo thorns, sewing needles, fish bone thorns, etc. are the easiest foreign objects to pierce the nail groove in daily life, and should be extra careful when participating in labor or busy with household chores. 3, usually pay attention to finger care, after washing hands, before going to bed rub some Vaseline or skin cream, can enhance the skin around the nail groove resistance to disease. 4, the finger has a small injury, can be coated with 2% iodine, band-aid bandages to prevent infection. 5, if the pus has been septic should go to the hospital in time to cut, the pus drainage out. Prevent the infection from spreading and causing osteomyelitis of the finger bone. 6.If pus accumulates under the nail, the nail should be removed to facilitate adequate drainage and complete healing. 7, wear shoes of appropriate size, fat and thin, suitable and light shoes. 8, diligently cut toenails, cut into arcs, nail grooves on both sides of the tip of the toenail, do not casually cut the nail groove, found that toes squeezed each other should be an appropriate amount of sterilized cotton, soft objects into the toe seam to separate, so that the toe normal development, to prevent pressure on the toenail into the nail groove.