If you frequently paint your fingernails, you'll notice they tend to have a yellowish hue after you've removed the nail polish. However, if your nails remain yellow over a period of days or after a lightening remedy (such as dipping your nails in lemon juice), the discoloration could have a more serious cause: diabetes.
Diabetes can lead to yellowing of both the skin and nails, but is usually more evident in nails [source: Huntley]. The color change is probably caused by glucose connecting with the collagen proteins in the nail [source: Oz].
If your yellow nails are not going back to a normal shade, and if you're also experiencing other symptoms of diabetes like increased thirst and urination, you should see your doctor right away.
There's another nail color that can indicate trouble. We'll explore it on the next page.