Foot thumb skin hardens and cracks considering the lack of vitamin A, scaly keratosis pilaris, chapped eczema, mainly medication, according to the specific cause of the selection of appropriate drugs. 1. Vitamin A deficiency: if the usual intake of vitamin A is too little skin will become drier and rougher, you can take vitamin A orally, apply aloe vera gel, petroleum jelly and other moisturizers, usually eat some vitamin-rich fruits and vegetables. 2. scaly keratinized foot: this is a kind of tinea pedis, it is caused by fungal infection, you can apply ketoconazole, amorolfine, and joint oral itraconazole, terbinafine. Usually can use salicylic acid ointment and other exfoliators to relieve. 3. Chapped eczema: chapped eczema is a type of chronic eczema, there will be hypertrophy, chapping and other symptoms, you can take oral chlorpheniramine, cetirizine, topical flumethasone ointment, fluticasone propionate cream, urea ointment and so on. Foot thumb skin hardened and cracked, should go to the hospital by the doctor to clarify the cause of the disease, standardized treatment, the above drugs need to be used under the guidance of a doctor.