Perinephritis is a purulent infection caused by minor trauma to the skin around the nail, manifesting as redness and swelling at the root of the perinephritis, which can gradually develop into an abscess under the nail. If it is early perineal infection, it can be treated with dermatology, oral antibiotics and topical application of 2% iodine tincture or Bactrim ointment, which can be cured in time; if the perineal infection is gradually aggravated without treatment and ulceration or sub nail abscess is formed, it should be treated with dermatological surgery or hand and foot surgery, and it should be cleaned and changed or incised to drain the pus, which takes longer time to treat and heals slowly, and if necessary, systemic application of Antibiotics should be applied systemically if necessary.