Can your fingernails and toenails give clues about your health?

Anthony L. Komaroff, MD
Internal Medicine
In general, looking at the fingernails and toenails is not a reliable way to tell if you are healthy or not. But a careful examination of the nails can provide clues to certain diseases.

Here are some examples:
  • Fungal infection: Toenail fungal infections affect up to 5% of the population. For most people, the condition is primarily cosmetic. Treatment is optional. But if an infection is painful or occurs in a person with diabetes, treatment may be offered.
  • Lung disease: Conditions such as lung cancer, lung scarring (pulmonary fibrosis) and cystic fibrosis may be associated with clubbing of the fingernails. With clubbing, the nails take on a raised, rounded appearance, like a club. But it's not completely reliable: many people with lung disease do not have clubbing and healthy people sometimes have clubbing, too.
  • Psoriasis: "Pitting" (small indentations) in the nails and thickening of the nails are common in people who have psoriasis. In fact, these nail changes may be the first or only sign of this condition.
  • Endocarditis (a heart valve infection): A heart valve infection is a serious condition, and can be hard to diagnose. Fever, shaking chills and rash are common symptoms. The appearance of multiple red lines under the nails -- called "splinter hemorrhages" -- may suggest the diagnosis.
  • Anemia: People with anemia tend to have pale nail beds. However, it's usually difficult to say whether a nail bed is pale enough to indicate anemia. Blood tests are more reliable.
Serious illnesses of almost any type can affect the appearance and growth of the nails. Your doctor may be able to tell if you were sick up to several months ago by the appearance of a horizontal ridge or indentation in finger nails, called Beau's lines. These lines may occur after any serious illness, including those associated with a high fever or severe nutritional deficiency. They may also appear soon after getting chemotherapy for cancer.

So, there are situations when the nails offer a glimpse into your health. But, most of the time, there are better ways.
Harvard Medical School Arthritis: Keeping your joints healthy

More About this Book

Harvard Medical School Arthritis: Keeping your joints healthy

If you have arthritis, you can take steps to protect your joints, reduce discomfort, and improve mobility all of which are detailed in this report. Because describing your symptoms is so important...

Continue Learning about Healthy Nails

How do I treat a badly injured nail?
Dr. Mehmet Oz, MDDr. Mehmet Oz, MD
A hammer, car door, or angry cat in the wrong place at the wrong time can leave your nail looking li...
More Answers
How should I cut my nails?
To trim nails, cut straight across with sharp nail scissors or clippers. Slight rounding of the tips...
More Answers
Sneak Peek: Are Gel Manicures Safe?
Sneak Peek: Are Gel Manicures Safe?
Health Clues from Your Fingernails
Health Clues from Your Fingernails

Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.