Most people don’t give a lot of thought to their fingernails beyond clipping or painting. However, the shape, texture, and color of your nails can be warning signs for serious conditions, including cancer. While some nail symptoms are harmless, others can be indicative of chronic diseases.
The American Academy of Dermatology (1) notes that changes in nails, such as discoloration or thickening, can point to health problems including liver and kidney diseases, heart and lung conditions, anemia, and diabetes.
If you notice any significant changes in your nails see a dermatologist right away. While it might be nothing, it could point to an underlying condition.
1. Yellow Fingernails
While your fingernails may become yellow with age or due to smoking, if they are also thicker and crumbly besides being yellow, a fungal infection is the most likely culprit.
More rarely, yellow fingernails can be related to thyroid disease, diabetes, or psoriasis.
2. Cracked or Brittle Nails
You nails can become cracked and brittle if you use nail polish remover frequently, or are exposed to chemicals (such as cleaning products).
However, cracking and splitting can also be a sign of a fungal infection or thyroid disease, particularly hypothyroidism. Brittle nails may point to a deficiency in vitamins A, B or C.
By James Heilman, MD – Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=24076773
If your fingertips become enlarged and the nail becomes curved downward, it may be a sign of clubbing. It can point to low oxygen in your blood, associated with lung disease. In extreme cases, it can be related to liver or kidney disease, heart disease, or even AIDS.
4. White Spots
These small white spots are usually the result of nail trauma and are not a cause for concern. They will disappear on their own. If they don’t go away, it could be a sign of a fungal infection.
5. Horizontal Ridges
Horizontal ridges, also known as Beau’s lines, are typically the result of direct trauma to the nail. They can, however, be a symptom of a more serious illness if they appear on more than one nail at a time. In this case, they may a result of psoriasis, uncontrolled diabetes, circulatory disease, or severe zinc deficiency.
There is a more serious type of horizontal lines, known as Mees’ lines. They are horizontal discolorations due to arsenic poisoning, Hodgkin’s disease, malaria, leprosy, or carbon monoxide poisoning.
6. Vertical Ridges
If you notice vertical ridges appearing in your nails that you didn’t have before, it’s probably nothing more than a side effect of aging (2). They’re equivalent to getting wrinkles in your skin and usually don’t appear until around age 50. Occasionally, nail ridges may be due to nutrient deficiencies, including vitamin B12 and magnesium.
7. Spoon Nails
This deformity is definitely visible enough to catch your immediate attention. Known as “spoon nails” (3), they most commonly appear due to an iron deficiency. The nail gets so thin that it becomes concave.
If you notice this, have some lab work drawn to determine if anemia is the issue. Other causes include working with petroleum-based products or trauma. In very rare circumstances, spoon nails can be associated with thyroid disease and heart conditions (4).
Multiple pits or dents in fingernails is often a sign of psoriasis. However, nail pitting may also be due to connective tissue disorders or alopecia areata, an autoimmune disease that causes hair loss.
9. Dark Discolorations
Any sort of asymmetric pigmentation can be a sign of skin cancer, but melanoma on nails (called subungual melanoma) usually looks like a pigmented vertical band stretching upward from the cuticle (5). If a brownish streak on your nail bed shows up suddenly or changes in appearance, see a dermatologist as soon as possible.
10. White Nails with a Strip of Pink (Terry’s Nails)
If you notice your nails become mostly white with a narrow pink strip at the top, known as Terry’s nails (6), it could be a sign of liver disease, congestive heart failure, kidney failure, or diabetes. But do not enter panic mode right away, Terry’s nails may appear due to aging.
11. Claws and Fur
If you notice that your fingernails are turning into claws and you are starting to grow fur on your hands paws, you are either a cat, or suffering from a very rare disease called clinical lycanthropy (not to be confused with werewolf syndrome). However, these symptoms can also be the result of old age.
Disclosure: While we did try to end the article on a comical note, please take any symptoms seriously and visit your dermatologist whenever you notice drastic changes on your nails.