What can my nails tell me about my health?

Q: I’ve noticed some odd changes to my nails that weren’t there before. What can our nails tell us about our health? And how can I keep my nails healthy?

A: Our nails are a unique window into our overall health. Many diseases are associated with distinctive nail changes — from the spoon-shaped nails of iron deficiency anemia to the rounded, swollen nails of cystic fibrosis.

In my third year of medical school, I met a patient who had come to the emergency room throwing up blood. After directing the rest of the team to stabilize the patient, the doctor in charge held the patient’s hand and looked closely at their fingernails. They were a frosty white, except for a strip of red at the tips. I’ve never forgotten that appearance (a finding known as “Terry’s nails”), or how the doctor turned to me and said, “I bet this patient has cirrhosis.”

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At first I was incredulous — how could she guess the patient had a liver problem of all things just by looking at the fingernails? But she was right: The patient had complications from cirrhosis.

Here are some common nail changes that can tell you something about your health:

Tracey Vlahovic, clinical professor in the department of podiatric medicine at Temple University, said that nail changes, like those that occur with psoriatic arthritis, might be an early sign of a systemic issue.

Keep in mind: Nails grow slowly (it takes about six months to regrow a fingernail), so not only could an abnormality reflect an illness that occurred several months prior, but any treatment prescribed to you may take time before you see results.

Since we’re talking about nails, it’s important to note that while manicures and pedicures may be visually appealing, they’re probably not doing much for the “health” of your nail, and some practices may be damaging.

Take pushing back cuticles, for example. You may have thought that the rather uncomfortable shoving and trimming of the cuticles is a necessary evil and that cuticles serve you no purpose.

Not so. Removing cuticles, in fact, increases the risk of an infection.

“Both your cuticles and the tip of your nail are there to keep the environment outside of the body,” said Vlahovic. “Scraping or pushing those areas back opens doors that should not be opened.”

She recommends only having nails filed and polished, or going to a spa that offers medical pedicures with instruments that have been sterilized with an autoclave device.

Popular gel manicures can lead to thinning of the nail plate and brittle nails due to the repeated application and removal process (often involving soaking with acetone and mechanical peeling). And I know I’m not in alone in having entered a Faustian bargain by wanting to cover damaged nails from a gel manicure with … another gel manicure.

Many supplements purporting nail growth contain biotin (and are taken daily by nearly 3 percent of U.S. adults). But according to the American Academy of Dermatology, there is no evidence that biotin promotes nail growth or quality in otherwise healthy people.

And taking biotin isn’t harmless: Biotin can interfere with blood tests such as troponin, used commonly to help diagnose a heart attack, and lead to a false negative result. This could have serious consequences, especially among women for whom heart attacks are already underdiagnosed.

Nail health is not something you want to self-treat. It’s easy to get the diagnosis wrong because many nail issues look similar. If you’ve noticed changes to the shape, texture or even color of your nails, talk to your provider about whether there’s any cause for concern.

Meet the doctor: Trisha S. Pasricha is a physician at Massachusetts General Hospital, an instructor in medicine at Harvard Medical School and a medical journalist.

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