Brittle nails, characterized by nails that split or peel into layers, affect as much as 20 percent of the population, according to a report by the University of North Carolina at Chapel Hill. Some health conditions can result in peeling of both fingernails and toenails, but if only your fingernails are affected, the cause is likely to be external.
Most cases of splitting nails are caused by moisture, according to the American Osteopathic College of Dermatology. Repeatedly wetting and drying your hands, and, by extension, your fingernails, can cause the nails to dry out. Too much moisture can also weaken the nails, softening them and causing them to peel. Fingernails can be protected from moisture by wearing gloves for activities in which the hands are immersed in water, such as washing dishes. The AOCD recommends applying a lotion containing lanolin to relieve dry and brittle nails.
Injuries to the nail can cause them to split and peel. Nail biting leaves fingernails ragged and prone to additional damage. Using your fingernails as tools for scraping and prying will also cause nail injuries, and nails can break and split during normal everyday activities. Keeping your nails trimmed short and filing them with an emery board into a rounded shape can prevent the splitting and peeling from getting worse.
Chemicals, including household cleansers, can dry out fingernails. Colored nail polish, adhesives used in glue-on nails and nail polish remover, particularly if it contains acetone, can all cause nail damage. The effects of chemicals can be remedied by limiting exposure and moisturizing the nails after contact. Applying a coat of clear nail polish once a week may also prevent damage, according to the American Osteopathic College of Dermatology.
Medline Plus states that splitting nails may be caused by hypothyroidism, a condition in which the thyroid gland is underactive and doesn't produce enough hormones. Other symptoms of hypothyroidism include weakness, fatigue, unintentional weight gain, joint pain and heavy menstrual periods. See your doctor if you experience these symptoms, as your peeling nails may have a medical cause.
Iron deficiency anemia may result in brittle nails, according to MayoClinic.com. Iron helps the body produce hemoglobin, the oxygen-carrying portion of red blood cells. Iron deficiency anemia can also cause cold hands and feet, pale skin, headaches and a poor appetite. A diet of iron-rich food or iron supplements can resolve the deficiency, but a doctor should be consulted to diagnose the problem if symptoms are present.