You notice: Spooned nails
It could be: Anemia or lupus. Do you have a depression in the toenail deep enough to hold a water droplet? Also known as koilonychias, spoon-shaped toenails or fingernails is most commonly associated with an iron deficiency, research shows, but it can also come from malnutrition, thyroid disorders, or injury. Spooned nails occasionally appear in infants, but normalize in the first few years of life. If you notice spooning, contact your physician, who will obtain a blood test to identify the exact cause. Check out what your nails reveal about your health.
You notice: A straight line under your toenails
iStock/Manuel Faba Ortega
It could be: Skin cancer. A dark, vertical line underneath a toenail could be acral lentiginous melanoma, or hidden melanoma—a form of the skin cancer that appears on obscure body parts. (Other hidden melanomas include eye melanoma and mouth melanoma.) “It will be a black line from the base of your nail to the end of the nail,” says Pichney. “It should be seen by a podiatrist or dermatologist. You want to make sure it’s not cancer, but it may be a fungus, which is usually yellow-brown and sporadic throughout the whole nail.”
You notice: A suddenly high arch
It could be: Nerve damage. “Most high-arched feet are associated with some form of underlying neuromuscular condition,” says Pichney. “If someone experiences thinning of the arch muscles in the foot, it could be an indication of a neurological condition called Charcot-Marie-Tooth (CMT).” An inherited disorder that damages the peripheral nerves (those outside the brain and spinal cord), CMT can also cause changes in gait, numbness in the feet, difficulty balancing, loss of muscles in the lower legs, and later on, similar symptoms in the arms and hands. See your doctor if you notice abnormalities. “For anything that’s different or changes when it comes to the foot, see your podiatrist right away,” says Reid. Also, watch out for these 42 strange symptoms that signal a serious disease.