When pigment-producing skin cells die, you're left with white spots that retain the same texture as the rest of your skin but lack melanin. This condition, known as vitiligo, affects up to two million Americans, the majority of cases occurring in people under 40. It's most noticeable where skin is usually a bit darker—hands, feet, arms, face, lips. But it can also occur in the armpits, nostrils, and even on your scalp. Researchers think vitiligo may be the result of an autoimmune disease that causes your body to mistakenly attack its own cells; it's associated with thyroid disease and Addison's disease (in which your adrenal glands stop producing enough of the hormones that help control everything from your immune response to your sex drive).
Protect Yourself: While there's currently no way to prevent most autoimmune diseases, you may be able to treat your white patches with corticosteroid creams, which have been shown to be effective in restoring some pigmentation. And I can't stress how important it is to wear sunscreen. Without melanin, your skin is at much higher risk for sunburns. To conceal the spots while shielding your skin, opt for a tinted moisturizer with at least SPF 30.