16 Disturbing Things Your Nails Reveal About Your Health

4. Darkened Nails

Nail discoloration can occur for many reasons. Green-black nails can be caused by bacteria overgrowth, particularly under loose nails. Brown nails are commonly caused by nail polish discoloration or pregnancy but could also indicate malnutrition or thyroid disease. Half-white, half-brown nails, or Lindsay's nails, are often seen in people with kidney failure, and are sometimes also experienced by those living with AIDS or receiving chemotherapy.

Look out for a dark stripe affecting only one nail, as this could be a sign of skin cancer and should be seen by a doctor.