After the nail cap of gray nail falls off, new nails will also grow. Gray nail usually refers to the nail lesions caused by dermatophytes invading the nail plate and nail bed, and in the clinical aspect, it is usually called onychomycosis, and gray nail is just the common name, which belongs to the dermatology of the more common diseases, especially preferred to the elderly, and men are more common. The main causative agent of nail fungal disease is the red trichophyton of dermatophytes, trichophyton fungus, Candida and so on, most of them are caused by the infection between tinea pedis. After invading the nail plate, the dermatophytes will release various enzymes that break down the nail plate, thus destroying the nail plate, so the nail plate will usually show the phenomenon of cloudiness, thickening, brittleness, discoloration, and peeling. After the diagnosis of onychomycosis disease, the patient should actively cooperate with the doctor for antifungal drug treatment, such as econazole, ketoconazole, itraconazole, terbinafine and so on. By actively cooperating with the doctor after treatment, the symptoms can be effectively relieved, as for the shedding of the nail cap, usually still grow out, do not need to worry too much.