Fingernails serve more than just a cosmetic purpose—they protect the delicate skin underneath and help with everyday tasks like scratching an itch or peeling fruit. However, doctors say that nails can also offer valuable insights into a person’s overall health, sometimes even signaling serious medical conditions.
A Window to Your Health
Doctors have long used fingernails as a diagnostic tool to identify potential health problems. Changes in color, thickness, or shape can indicate anything from nutritional deficiencies to serious illnesses like lung disease or diabetes.
One of the most well-known signs doctors look for is clubbing, a condition where the nails curve downward and the fingertips appear swollen. “One of the first things I learned in medical school was to look for clubbing,” says Dr. Dan Baumgardt, a general practitioner and lecturer at the University of Bristol. Clubbing is often associated with low blood oxygen levels and can be an early sign of lung cancer, heart infections, or liver disease.
Color and Texture Clues
A healthy nail bed should be pink, with a white crescent-shaped lunula at the base. Any significant discoloration can indicate an underlying issue.
- White or yellow nails: These could point to fungal infections, especially in toenails. Dr. Holly Wilkinson, a wound healing expert at the University of Hull, warns that untreated fungal infections can become difficult to manage.
- Brittle nails: Weak, easily broken nails may suggest hypothyroidism or a vitamin B7 (biotin) deficiency.
- Horizontal ridges (Beau’s lines): These may indicate protein deficiency, diabetes, or peripheral vascular disease, a condition that restricts blood flow.
Spoon-Shaped Nails and Nutritional Deficiencies
Another condition, koilonychia, causes nails to become thin and concave, resembling spoons. This can be a sign of iron-deficiency anemia, where the body lacks enough healthy red blood cells to carry oxygen. In some cases, it can also indicate celiac disease.
“Nail shape can tell us a lot,” says Dr. Mary Pearson, a pediatrician at the University Hospital of Wales. “When we suspect chronic disease or malnutrition, examining a child’s nails can provide critical clues.”
Lifestyle Factors at Play
Not all nail changes point to serious health problems—some may be linked to everyday habits. Peeling nails (onychoschizia) can result from excessive handwashing, dry nails, or frequent use of acrylics and nail polish, according to Dr. Joshua Zeichner, a dermatologist at The Mount Sinai Hospital in New York.
While minor nail changes are often harmless, experts emphasize the importance of seeking medical advice if significant changes occur. Whether it’s a sign of an underlying condition or simply a call for better nail care, your fingernails may be telling you more than you think.
