Thickening of the toenails of the big toe may be due to nail fungus or nail dystrophy. Nail fungus is caused by fungal infections and is usually more likely to occur in cases of nail trauma, manifesting as thickened toenails, uneven surface and loss of luster, debris under the nail, and in severe cases, pain and discomfort. The main treatment is to give antifungal drugs orally, such as itraconazole, terbinafine, fluconazole, etc. are now commonly used orally. Generally toenail need continuous medication for more than four months, during the medication need to monitor liver function, because antifungal drugs are metabolized by the liver, long-term medication must monitor liver function, and nail dystrophy can also be manifested as a thickening of the nail plate loss of luster, the surface of the longitudinal ridge, free nail edge easy to separate, nail easy to break, nail dystrophy etiology is unclear, it may be combined with other skin diseases, such as baldness, psoriasis, lichen planus, etc, There is no special treatment for nail dystrophy, sometimes it can be relieved by itself, you can try oral cod liver oil and vitamin E.