From thyroid issues to cancer, here's what your fingernails can tell you about your health

Hamilton Spectator

a day ago

There's more to fingernails than hangnails and nail polish.
In fact, your nails can reveal surprising facts about your health, if you're paying close enough attention. They can be clues to problems with your blood, thyroid gland, immune system, heart, liver and gastrointestinal system.
'Be vigilant for changes to the nails in general,' said Kendall Billick, a dermatologist at UHN who runs Canada's only medical clinic dedicated to nails. 'Those could be signs of something totally not worrisome, or a sign of internal conditions.'
Here's what to watch out for, and what it could mean.
This is a common complaint that Paul Cohen, a Toronto-based dermatologist at the Rosedale Dermatology Centre, hears from his patients. Often, this doesn't indicate an underlying health issue — it points simply to the way you take care of your hands.
Nail polish remover, cold and dry weather, frequent handwashing and too much hand sanitizer are common causes of brittle nails. 'The harsh environment can affect the way the nails grow,' Cohen said.
On rare occasions, brittle nails can be caused by a medical condition, like the thyroid gland not working, but it's more often a sign of how you're caring for your hands, according to Cohen.
He recommends using lots of hand moisturizer — especially ones that include urea, an ingredient that attracts water — and using gloves while washing the dishes and cleaning with harsh chemicals.
If you're protecting your nails and they're still brittle, Billick recommends asking if there is something else going on.
'The most important thing to know about nails,' Cohen said, 'is when you have to worry about melanoma.'
People often associate skin cancer with moles on their skin, but it can also pop up in the nail as a dark stripe changing in size and shape. These stripes can be naturally occurring, especially in people of colour, or caused by medication or other health concerns, but they shouldn't be ignored — 'especially if that brown stripe is changing in appearance,' Cohen said.
These stripes often get overlooked because they usually don't cause pain or discomfort, Cohen said, but can have severe consequences.
'It's more common to have bands the darker your skin tone,' said Billick, also an assistant professor at the University of Toronto. 'But any changing band, especially if it's in a single digit, should prompt a call to your doctor to have it assessed.'
There are many different types of nail lines, Billick said, and many different colours they can appear as. The most common reason for a white line is trauma to the nail, typically from manicures.
Depending on if they're located in the nail or beneath the nail, white lines can also indicate exposure to toxins, like undergoing chemotherapy, or low levels of protein in your blood — which can, in turn, be a symptom of kidney or liver disease, according to Heidi Engelhardt, a professor at the University of Waterloo who specializes in physiology.
If you're seeing a line, Billick recommends asking about it on your next checkup.
'There's very little in the nail, except very nuanced and painful conditions, that can't wait for a future visit,' Billick said.
White marks on the nail can also be caused by nail fungus, Engelhardt said.
But Billick also sees many people come to his clinic because of a so-called fungal infection that isn't improving with drugs — and that's because, most of the time, they don't actually have a fungus infection, he said. Often, it's another condition that has been misdiagnosed.
'Don't accept antifungal or antibacterial treatment without a firm diagnosis,' Billick said, which can be done through a nail sample.
Ridges or dents that appear in the nail are called Beau's lines. The most obvious cause is trauma to the nail, like being slammed in a door or hit by a hammer, Engelhardt said.
But if that hasn't happened and the ridges appear on multiple fingers or toes, it can indicate interrupted nail growth under stress or illness — potentially diabetes, hypothyroidism, a skin condition like psoriasis or vitamin deficiencies.
Engelhardt recommends taking multivitamins and asking a doctor.
Billick recommends avoiding manicures and pedicures, as that's the 'single biggest problem' he sees in his clinic. And if you can't avoid them, don't let the nail technician cut the cuticle at the base of the nail.
'It's a seal that prevents dirt, germs (and) water from getting to the factory that produces the nail,' Billick said. Once it's cut, 'all sorts of bad things happen.'
Billick also recommends not using artificial nails or UV lamps.
And avoid biotin supplements, too. They simply don't work, according to Billick, and also interfere with blood tests — even producing false results after a heart attack.
Overall, Billick believes many doctors and the public underestimates how much nails can impact quality of life. In his clinic, he's seen a woman who felt her nails were preventing her from getting married, a businessman who felt he couldn't shake on a deal and an optometrist who was embarrassed to show people glasses on account of her hands.
'If nails are affecting quality of life,' Billick said, 'I think that's a very reasonable thing to bring to someone's attention.'