Many of us don’t think twice about what our fingernails look like, but they can actually say an awful lot about the state of our overall health.

John Anthony, MD, a dermatologist at the Clevland Clinic in Ohio and Debra Jaliman, MD, a New York City-based dermatologist, both say that there are certain fingernail symptoms that you should not ignore.

Yellow Nails: This color fingernails is often the result of a fungal infection, but they also be an indication of a more serious condition like diabetes, thyroid disease or lung disease. Anthony warned that smoking can be another cause of yellow fingernails, and you should quit if your fingernails start turning this color.

Cracked or Brittle Nails: Jaliman said that this is a sign that your nail plate is dry. It can also be a sign of thyroid disease or hypothyroidism, which is a condition in which the thyroid is not producing enough hormones.

Pitted Nails: This is caused by the defective development of the layers of the nail plate, and it is often a symptom of psoriasis. Jaliman said you should talk to a doctor immediately if you notice this happening to you.

Discolored or Dark Lines Beneath: This could be a sign of a melanoma, which is the most dangerous type of skin cancer. Anthony explained that the melanoma that comes from the nail unit is extremely serious and can also cause a black line or stripe on the nail.

Bluish Nails: If your nails are turning this color, it’s a sign that your body is not getting enough oxygen, possibly due to lung problems and heart problems. Consult your doctor immediately if you notice your fingernails turning blue!

Have you experienced any of these issues? Let us know in the comments section, and please SHARE this story so your friends and family can see this as well!