A fungal infection can cause the nails to change colors. Changing of nail appearances may also be caused by a more serious condition, according to WebMD.
The condition of a person's health may be determined by the look of their nails. Discoloration may be caused by a vitamin deficiency or an auto immune disease such a lupus. Fingernails with a slight yellow tint may be a sign of diabetes. If the nail is yellow and thick, lung disease may be the cause. White nails are a symptom of anemia. A doctor should check the nail beds if there is a sudden change in their appearance.