Nail fungus is an infection of the nail groove or its surrounding tissues. 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 organism is mostly Staphylococcus aureus (the proximal side of the nail – the nail root – is closely attached to the skin, and the skin extends along both nails distally, forming a nail groove). Nail fungus is most often seen in adolescents or women. It usually occurs in the fingers or toes, often with a bad habit of gnawing on the fingers, and in the toes, often caused by secondary infection from ingrown nails. 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, which keeps the wound from healing for a long time. The nail infection can be divided into acute nail infection, chronic nail infection, purulent nail infection, simple nail infection, and ingrown nail infection depending on the cause and clinical presentation. Acute onychomycosis: 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 reduced, the integrity of the skin around the nail is destroyed, or the number and virulence of the pathogenic bacteria is too great, infection will 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 an abscess under the nail, which can also develop into chronic nail infection and chronic osteomyelitis of the finger bone, with chronic sinus tracts and granulation tissue protruding outward from the sinus opening. Chronic nail fungus: Mostly occurs when acute nail fungus is not treated promptly or is re-infected, and the nail becomes uneven and pitted. The nail may show green, yellow or black signs of infection under the nail. Mostly caused by fungal infections, diabetic patients and those who work with hands often immersed in water, such as housewives, fishermen, cleaners, bartenders, and cooks, are prone to chronic nail infections. Septic nail fungus: Septic nail fungus is a purulent inflammation caused by untreated acute nail fungus. The nail groove has mild redness, pain, peeling of the small skin of the nail, a small amount of pus flows from the nail groove, the edge of the nail and the nail groove becomes black and can gradually produce nodular or myxoid protrusions of inflammatory granulation tissue, from time to time secrete pus, easy to bruise and bleed, part of the nail is damaged, the nail is deformed and reduced, there are longitudinal ridges or transverse grooves on the nail, there is pus sneaking under the nail. In severe cases, the nail can be completely loosened and fall off. Simple nail fungus: Most simple nail fungus is located in the first toe of the foot, one or two angles at the front of the nail pierce deep into the nail groove and do not grow out, every 2 weeks to 1 month, the toe will have a swelling and pain, accidentally touching it will have a sharp pain, the pain will disappear after cutting it with a knife, but after a while it will appear again. If you walk for a long time or do not trim your toenail, your toe may become swollen and red, and you may even develop oozing and granulation-like tissue in the nail groove. Ingrown toenail: Ingrown toenail is a nail infection caused by a toenail that has grown into the flesh. After more than 3 weeks of inflammation in the nail groove of the toe, it is considered to be due to an ingrown nail. Most often seen in the thumb, the laterally growing nail plate grows into the nail crease wall, resulting in pain and inflammation and, in severe cases, septic symptoms. It is clinically prevalent in women, such as too much nail trimming, too tight shoes, and too high heels. The nail is not a good idea to cut your nails too short, and you should not use your hands to pull out the “barbs”. 2, prevention is better than cure. Wooden thorns, bamboo thorns, sewing needles, fish thorns and other foreign objects that are most likely to pierce the nail groove in daily life, participate in labor or busy with household chores, should be extra careful. 3, usually pay attention to the maintenance of the finger, after washing hands, before going to bed rub some olive oil or skin cream, can enhance the skin around the nail groove resistance to disease. 4.When there is a small injury to the finger, you can apply 2% iodine to prevent infection. 5, if the pus has been septic, you should go to the hospital in a timely manner to cut open and drain the pus 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.