Nails: A window to your health

Nails: A window to your health

Your fingernails and toenails are a window into your overall health. Many health conditions, such as heart and lung disease, are very visible in the nails. Bands or lines in multiple fingernails, as well as changes in color, can also indicate illness. Nails can even tell you how long you’ve been ill since fingernails need six months to grow, and toenails a whole year.

When was the last time you looked at your nails?

Did you know:

  • Nail pitting: Small depressions on the surface of the nail; is common in people with psoriasis
  • Clubbing: Enlarged fingertips with nails curving around the fingertips may indicate lung, liver, heart or inflammatory bowel disease, or AIDS
  • Spooning: Scoop-shaped nails that curve up may be a sign of anemia
  • Banding: Indicates an interruption in the nail’s growth – may be a sign of uncontrolled diabetes, peripheral vascular disease or past illness with high fever
  • Yellowing: May be caused by respiratory disease or lymphedema (swelling of your hands or feet)
  • Nail fungus/other infections: May cause discoloration, thickening, crumbling edges or split nails
  • Vertical ridges: Fairly common – nothing to worry about

Watch a video to learn more at

John Knox, MD
The condition you describe sounds interesting. The lack of symmetry should rule out any internal cause. The length of time it has been present should rule out any medical necessity to treat the condition except in the unlikely event that it changes. Trauma does sound like a plausible explanation. There could also be a growth like a mole under the nail distorting its growth. Unless the lesion changes I would not be concerned about what the cause is. Only a biopsy would give more information and there is always a chance of complications from any surgery. It would obviously be nice if there was an easy way to fix the nail. Unfortunately when lesions are excised there is a good chance that the nail may not grow together and you might have a split nail.
3/26/2013 9:46:09 AM
J. K.
For at least 50 of my 65 years, my left thumbnail grows out looking like a horizontal wave; that is, it starts as a "spooning" depression at the base and as it grows out, the upper edge curves up and appears like a rounded "bump." Then the nail at the base begins to grow out flat but becomes a bump, followed by another depression.
Someone told me it was likely due to old trauma injury underneath the nail base, but I never had an injury to that thumb.
My right thumbnail is normal.
Any ideas?
Thank you.
3/25/2013 5:19:26 PM
John Knox, MD
A relatively new very dark streak in a nail is definitely worrisome. People with darker skin frequently have streaks of pigment in the nails are normal. It is very difficult to make a comment without actually seeing all 20 nails and a person's skin in general, so consider talking to your health care provider or you can call my office at 206-386-9540 to request an appointment or go to
2/28/2013 9:16:37 AM
How about a darker vertical line that runs from the cutip to the tip of the thumb nail on one side of the nail...almost looks like a darker shadowing or llight gray section? And what about a darker toe nail, medium gray colored on the second or last toe nails? Anything to be worried about? I viewed your presentation online but nothing was noted about these symptoms. Please advise. Thank you.
2/27/2013 10:21:20 AM
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