The shape, texture, and color of your natural nails act as a window into your body, and while some nail symptoms are harmless, others can be indicative of chronic diseases, including cancer. As noted by the American Academy of Dermatology (AAD):
“Nails often reflect our general state of health. Changes in the nail, such as discoloration or thickening, can signal health problems including liver and kidney diseases, heart and lung conditions, anemia, and diabetes.”
Even the growth rate of your nails may give clues about your underlying health. Healthy nails grow, on average 3.5 millimeters (mm) a month, but this is influenced by your nutritional status, medications, trauma, chronic disease, and the aging process itself.
If you notice any significant changes in your nails, including swelling, discolorations, or changes in shape or thickness, see a dermatologist right away. It could be nothing, or it could be due to an underlying condition (for instance, nail problems are more common in people with diabetes).
Below are 10 nail symptoms you might experience in your lifetime and what they mean for your health.
10 Nail Symptoms and What They Mean for Your Health
1. Yellow Nails
Your nails may yellow with age or due to the use of acrylic nails or nail polish. Smoking can also stain nails a yellowish hue. If your nails are thick, crumbly, and yellow, a fungal infection could be to blame.
Less often, yellow nails may be related to thyroid disease, diabetes, psoriasis, or respiratory disease (such as chronic bronchitis).
2. Dry, Cracked or Brittle Nails
Lifestyle factors may play a role here, such as if you have your hands in water a lot (washing dishes, swimming, etc.)
Clubbing describes when your fingertips become enlarged and the nail becomes curved downward. It can be a sign of low oxygen in your blood and is associated with lung disease. Clubbing can also be related to liver or kidney disease, heart disease, inflammatory bowel disease, and AIDS.
4. White Spots
Small white spots on your nails are usually the result of nail trauma. They’re not cause for concern and will fade or grow out on their own. Less commonly, white spots that do not go away could be due to a fungal infection.
5. Horizontal Ridges
Horizontal ridges may also be due to trauma or a serious illness with a high fever (such as from scarlet fever or pneumonia). John Anthony, M.D., a dermatologist at the Cleveland Clinic in Ohio, explained them this way to TIME:
“This is typically the result of direct trauma to the nail or a more serious illness, in which case you’ll see it on more than one nail at a time … Your body is literally saying, ‘I’ve got better things to do than make nails’ and pauses their growth.”
Horizontal ridges, also known as Beau’s lines, may also be due to psoriasis, uncontrolled diabetes, circulatory disease, or severe zinc deficiency. Another type of horizontal line is known as Mees’ lines, which are horizontal discolorations that may be due to arsenic poisoning, Hodgkin’s disease, malaria, leprosy, or carbon monoxide poisoning.
6. Vertical Ridges
Vertical ridges are typically a normal sign of aging and are not a cause for concern. They may become more prominent as you get older. In some cases, nail ridges may be de to nutrient deficiencies, including vitamin B12 and magnesium.
7. Spoon Nails
Nails that curve upward at the edges, taking on a spoon-like appearance, may be a sign of iron-deficiency anemia, hemochromatosis (excess iron absorption), heart disease, or hypothyroidism.
If your nails have multiple pits or dents, it’s often a sign of psoriasis. Nail pitting may also be due to connective tissue disorders (including Reiter’s syndrome) or alopecia areata, an autoimmune disease that causes hair loss.
9. Dark Discolorations
Black streaks or painful growths on your nail warrant an immediate trip to your physician, as they may be due to melanoma, the deadliest form of skin cancer.
10. White Nails with a Strip of Pink
If your nails are mostly white with a narrow pink strip at the top, known as Terry’s nails, it could be a sign of liver disease, congestive heart failure, kidney failure, or diabetes. Sometimes Terry’s nails may also be due to aging.