You could do everything else right: eat the best foods for your skin, be up to date on the latest in anti-aging skin care and tirelessly slather on sunscreen -- but if you're neglecting your hands, all your efforts to harness the fountain of youth are for naught.

As Debra Jaliman, MD, New York dermatologist and author of "Skin Rules" says, "If you're going to take great care of your facial skin, but your hands don't match, what's the point?" We talked to Jaliman and Jessica Wu, MD, Los Angeles dermatologist and author of "Feed Your Face," to see what visible signs of aging your hands show, and how to prevent them.

Image via Imaxtree

Common misconception: Your liver is the culprit behind those brown spots on your hands. Not true. "Brown spots are caused by the sun," says Wu. However, they start to pop up as you age because your hands are exposed to the sun more than the rest of your body.

"Many of my patients are diligent about using sunscreen on their faces, but forget about protecting their hands," says Wu. "Even if it's cold outside, the sun can be bright, and UV rays can make brown spots worse."

To avoid brown spots (and keep more from appearing), always wear sunscreen on the backs of your hands. Use a daily lotion with SPF 30-50, with broad-spectrum UVA and UVB protection. Many hand creams now come with built-in sunscreen. We like Supergoop Forever Young Hand Cream SPF 40.

Wu says you can also go vintage by keeping a pair of driving gloves in your car. Alternately, hold the steering wheel in the six o'clock position with your palms up.

So, you haven't been diligent with your sun protection. Luckily, there are some ways to treat brown spots -- especially if you start early. "Newer, light brown spots may respond to lightening and brightening creams with ingredients such as soy, arbutin, and vitamin C, or prescription retinoid and hydroquinone," Wu says.

Try a serum like Mario Badescu Vitamin C Serum, or a moisturizing hand lotion like Ahava Age Perfecting Hand Cream (it contains a blend of dead sea minerals and nourishing algae).

If you're dealing with dark spots that have been around longer than a year, you'll need to make an appointment with your dermatologist. Your doctor can treat spots with a laser, like PicoSure (the first picosecond laser to be FDA-cleared to treat benign pigmented lesions), or a chemical peel.

Are your brown spots lumpy, as well? "For raised brown spots, I sometimes treat with liquid nitrogen, which freezes them off," says Wu.

If you don't take care of your nails, you basically seal their fate: dry, cracked, and ridged, which drastically ages the appearance of your hands.

Nails also begin to show vertical stripes, which Jaliman calls the "wrinkles" of the nails. No thank you.