Nail frenulitis is an inflammatory reaction involving the skin folds around the nail that presents as acute or chronic purulent, tenderness and painful swelling of the perinail tissue, caused by an abscess in the nail fold. When the infection becomes chronic, transverse ridges appear at the base of the nail and new ridges appear with recurrence. The fingers are more commonly involved than the toes. The main susceptibility factors are injury resulting in separation of the nail epithelium from the nail plate and secondary invasion of septic cocci or yeasts into the moist nail grooves and nail folds. The common pathogenic bacteria are Staphylococcus aureus, Streptococcus pyogenes, Pseudomonas, Aspergillus or anaerobic bacteria; the most common pathogenic yeast is Candida albicans. 1. Treatment Acute nail fungus should be treated as soon as possible to prevent nail bed damage. Choose broad-spectrum antibacterial drugs that cover aerobic and anaerobic bacteria, such as amoxicillin/clavulanic acid, and if symptoms do not improve in 48 hours, surgical treatment should be taken. Chronic onychomycosis is treated with antifungal drugs (azoles are preferred) or antibacterial drugs as needed, and treatment needs to continue until the inflammation subsides and the nail tubercle rebuilds and adheres to the nail plate, often for more than 3 months. In patients with recurrent acute exacerbations, treatment may be intra-dermal or systemic application of glucocorticoids combined with systemic antibacterial drugs for 1 week. Acute nail infections may be treated with incision and drainage when the infection is superficial and limited. If the infection is deep, under local anesthesia, the proximal 1/3 of the nail plate is lifted and a drainage strip is placed under the proximal nail crease to drain the secretions. Chronic nail infections secondary to ingrown nails can be treated by simply removing the nail plate. Topical azole antifungal medication or topical clarithromycin solution is used in combination with anti-inflammatory therapy, such as topical medium- or strong-acting glucocorticoid creams. For those who fail in conventional treatment, surgical treatment or low-dose superficial radiation therapy can be adopted. 2. Prevention Prevention of small shoes and diligent toenail clipping are the fundamental methods to prevent nail fungus. When cutting nails, pay particular attention to the trimming of the nail groove to prevent ingrown toenails. When there is pain next to the nail groove, it is more important to pay attention to the disease and consult your doctor.