Tinea capitis, commonly known as gray nails, is caused by a fungal infection. Iodine volts are not an effective drug for treating gray nails, and treatment with iodine volts often does not work. In the past, some patients were cured by removing the diseased nail and then applying iodophor, but this method is rarely used now because the operation is painful and invasive. Gray nails are generally treated with topical and oral antifungal medications. For nail fungus that is relatively small in area and does not destroy the entire nail, topical medications alone can be used. It is best to use topical medication that has a strong penetrating effect on the nail. Try to trim off the diseased part of the nail and apply medication such as 5% amorolfine rub, which is usually used 1-2 times a week for more than 6 months. And if the entire nail or even the nail root is diseased, the effect of topical medication is not too good case, for patients with normal liver and kidney function, you can choose oral medication, such as itraconazole, terbinafine.