What that weird dent or blotch on your nail might be saying about your health

The signs are right in front of you.

The signs are right in front of you

(Getty Images/iStockphoto)

This article was originally published April 20, 2017.

Most of us only pay attention to our nails when they break, need cutting or get manicured.

But look closer, because they could be trying to tell you something.

"If you notice a change in your nails, that may indicate something wrong with the body as a whole, or it may indicate an abnormality locally within the nail," said Dr. Harvey Lui, head of the department of dermatology and skin science at the University of British Columbia. "The range of changes in the nail can go all the way from a potentially life-threatening disorder to something that… just happens on your nails."

Indeed, changes to your nails can indicate anything from an iron deficiency to spending too much time in the water to signs of cancer.

To learn more, we asked Lui and Dr. Katie Beleznay, a Vancouver-based dermatologist, to tell us what nail abnormalities to look out for, which ones are serious and which ones aren't, and what to do if you notice a change in your nails.

Spoon-shaped nails

(Source: medicalpicturesinfo.com)

What: If your nails are thin and curve inward, this could be a sign of iron deficiency anemia. The condition itself is called Koilonychia.

What to do: See a doctor who can test your blood to see if you are indeed iron deficient. The doctor may then prescribe iron supplements.

Green nails

Green nails = infection with a bacteria called “Pseudomonas”. Not all bacterial infections are green, only the ones caused by Pseudomonas. (Source: Dr. Harvey Lui and University of British Columbia)

What: When nails appear green in colour, this could be due to a bacteria called pseudomonas. The bacteria, which creates a green pigment, typically affects people who often submerge their nails in water, such as a dishwasher.

What to do: See a doctor who can treat the condition with diluted bleach.

Yellow nails

(Source: mddk.com)

What: Yellow nails could be a symptom of anything from lung disease to smoking cigarettes to wearing dark coloured nail polish.

What to do: If you smoke, stop, and see a doctor to find out if the yellowing may be a sign of lung disease. If you wear nail polish, use a base coat and avoid darker shades. If the problem persists, see a doctor.

White-ish yellow, crumbly nail

Subungual keratosis = thickened nails with keratin build-up – may be due to fungus infection or sometimes other diseases like psoriasis (Source: Dr. Harvey Lui and University of British Columbia)

What: It's probably a fungal infection. This occurs when a fungus gets into the nail and starts destroying it from the inside out. The older you are, the higher your chance of getting nail fungus.

What to do: See a doctor – soon. It's better to treat this problem earlier rather than later, but even with treatment, the fungus may come back, warns Lui. Your doctor may prescribe an oral antifungal medication or treat the fungus with a topical medication.

Brown or black streaks in the nail

(Source: regionalderm.com )

What: Dark marks in the nail, known as longitudinal melanonychia, could be caused by anything from a mole within the nail, a trauma to the nail or – rarely – skin cancer.

What to do: Most nail traumas will eventually grow out, but if you don't recall hurting your finger or toe nail, or if you're otherwise concerned about the mark, see a doctor.

White round or oval spots

Leukonychia = white spots on the nails. Generally this is not serious and usually transient (Source: Dr. Harvey Lui and University of British Columbia)

What: These marks, called leukonychia, are common. They typically appear when the nuclei in the nail cell don't dissolve, leaving a white mark instead of the usual transparency. The mark is nothing to be concerned about and doesn't indicate any sort of vitamin deficiency – a common misconception, said Lui.

What to do: Let the mark grow out.

Katrina Clarke is a Vancouver- and Toronto-based journalist who writes about relationships, health, technology and social trends. You can find her on Twitter at @KatrinaAClarke.