Disappearance of crescent moon on hands may be caused by lack of nutrients, lack of trace elements, onychomycosis, anemia and so on. 1. Lack of nutrients:such as vitamin B and vitamin E, will lead to malnutrition of the nails, which will lead to the absence of the crescent moon on the nails. 3. Lack of trace elements:If the crescent moon on the hand disappears, the fingernails at the same time appear broken nails, fragile and brittle and other symptoms, belong to the body of calcium, zinc ions and calcium ions lack, to carry out appropriate calcium and zinc supplement. 4. Inflammation of the nail:If the patient has obviously experienced an infection of the hand, such as inflammation of the nail groove, the crescent of the fingernail will also be reduced due to the infection. 5. Anemia:If there is severe anemia in the body, it can also lead to the absence of crescent on the fingernails. There are many reasons for the disappearance of the crescent moon on the hand, if it is caused by disease, we should pay attention to it, we should go to the hospital in time to check, find out the cause of the disease, and cooperate with the doctor to carry out targeted treatment.