There are many reasons why the edges of the nails become hard and cracked, commonly including lack of protein or vitamins, chemical stimulation, fungal infections and so on. 1. Lack of protein or vitamins: Eat more high-protein foods, such as milk, eggs, eat more fruits and vegetables, such as cucumbers, oranges, kiwis, etc., these foods are rich in vitamins, can be a lack of vitamins in the body to replenish, but also can add some water, can improve the symptoms. 2. Chemical stimulation: often in life can come into contact with chemicals, such as laundry detergent, detergent and other stimulating ingredients containing chemicals, the skin around the nails to stimulate, thus causing the edge of the nail peeling, cracking and other symptoms; 3. Fungal and bacterial infections: ringworm occurs when the hands are infected by fungi, mainly infecting the fingers, palms and the lateral edges of the palms in these locations. If the skin of the palm and fingers appear excessive keratinization, the place of the edge of the nails will appear dry, peeling, cracking and other symptoms, cracking is easy to secondary bacterial infection, causing perinailitis. If you have symptoms of peeling, hardening and cracking at the edge of your nails, seek medical attention and treatment under the guidance of your doctor.