At salons around the country, nails
are big business. But beneath the polish, your digits can be a window into your overall health. “Many health conditions are very visible in the nails,” says John Knox, MD, of Swedish Medical Center in Seattle. They’re a unique indicator because of their partial transparency. Nails can even tell you how long you’ve been ill, since fingernails need six months to grow, and toenails a full year. Knox points out that even nail-biting can be an indicator of mental health. “Patients who are more anxious or obsessive compulsive do tend to bite their nails more frequently,” says Dr. Knox.
A wide variety of diseases can be detected by looking at changes your nails. Lung disease and lymphedema can cause yellow discoloration, while psoriasis can look like fungus. Bands, or lines in multiple fingernails, as well as changes in color, can also indicate illness. Paying attention to your nail health is important, but Knox also notes that some nail issues have simple explanations: “Poor nutrition will cause brittle nails, but so will aging, excessive washing, and a variety of different things.”