Possible causes of thickened nails include nail fungus disease, psoriasis nails, and nail dystrophy, which can be helped by topical and oral medications. 1. Nail fungus disease: Nail fungus disease, commonly known as gray nails, is caused by a variety of fungi that invade the finger (toe) nail area, which can manifest as nail turbidity, thickening, separation and other symptoms. Because it is difficult to penetrate into the finger (toe) nails with topical medications, oral antifungal medications are usually needed for systemic antifungal treatment, such as terbinafine or itraconazole. 2. Psoriasis nails: When psoriasis involves nail beds, nail matrix and other nail parts, it will cause symptoms such as nail thickening, depression and accumulation of flakes. It can be applied locally by using ointment such as captopanol betamethasone ointment and tretinoin urea ointment to help improve the symptoms, and in serious cases, oral methotrexate, cyclosporine and other immunosuppressants are needed. 3. Nail malnutrition: Lack of calcium, iron, zinc and other trace elements in the body may cause depression, vertical lines, thickening and other symptoms on the fingernails. Such patients should pay attention to strengthen the nutrition, you can take some vitamins, calcium and zinc oral solution to help supplement the body’s lack of trace elements, and then improve the thickening of nails. Nail thickening may also be caused by other reasons, it is recommended to consult a professional doctor for standardized diagnosis and treatment in a timely manner. The above treatments should be carried out under the guidance of a physician to avoid the occurrence of adverse reactions. The use of medication should be in accordance with medical advice.