You've heard them all before ‑- chocolate gives you pimples, tanning beds only expose you to the "good" UV rays, stress makes acne flare. In fact, myths about skin are so pervasive it's hard to remember which ones are true and which are false. We asked three top dermatologists to set the record straight on the most common misperceptions and beliefs.

1. Fatty foods cause acne. "There's no scientific evidence that any foods cause acne," says Sarah R. Scott, MD, a dermatologist at the Ochsner Clinic in New Orleans. Many factors contribute to acne, including bacteria and fluctuating hormones that may lead to an overproduction of oil. Genetics also come into play: If your mother or father had acne, chances are you will.

Acne isn't a result of bad hygiene either: In fact, overcleaning your face can lead to irritation, which can exacerbate acne by causing inflammation and redness, says Dr. Scott.

2. You can't get skin cancer where the sun don't shine. "Malignant melanoma can occur anywhere on the body because genetics also play a role in its development," says Diane Berson, MD, assistant professor of dermatology at Weill Medical College at Cornell University. People also mistakenly assume that if they tan easily or they're olive- or dark-skinned, they don't have to worry about skin cancer. While it's true that those with darker complexions have more melanin, which protects the skin cells from becoming damaged and turning cancerous, that doesn't mean they're at no risk for the disease. Everyone should keep an eye out for any suspicious or new moles, especially in hard-to-see areas like the ears, armpits, soles of the feet, buttocks and genitals. It's also important to get an annual mole check by your dermatologist.