A: What's probably up are your memory T cells, which can react to an allergen days, months, even years after exposure, says Valerie Callender, MD, associate professor of dermatology at Howard University. One of the most common causes of allergic contact dermatitis (ACD) is fragrance ingredients. But don't give up on your perfume just yet; some of these ingredients are also found in skincare and haircare products and laundry detergents. Decrease your exposure to all scented products, says Paradi Mirmirani, MD, a dermatologist at Kaiser Permanente in Vallejo, California. Then apply your fragrance on the inside of your arm to see if that's what's causing your reaction.
Keep in mind: A doctor can give you a patch test to determine if you have ACD; if you don't, you may have irritant contact dermatitis, which, though often less serious, can also cause a rash.
Q: Which do I put on my face first, sunscreen of moisturizer?
A: What you apply first depends on the kind of sunscreen you use. A physical block (containing titanium dioxide or zinc oxide) can be applied over your moisturizer. But a chemical sunscreen (avobenzone or oxybenzone), which works by interacting with your skin to absorb the sun's rays, must penetrate whatever is already on your face in order to be effective, says Heidi Waldorf, MD, associate clinical professor of dermatology at Mount Sinai School of Medicine. So it's smart to apply this type before anything else.
Keep in mind: In summer, unless your skin is very dry, you can probably use just one product: a moisturizing sunscreen. I like PCA Skin Protecting Hydrator SPF 30 ( $34, pcaskin.com for stores) and Yes to Cucumbers Soothing Daily Calming Moisturizer with SPF 30 ($15, yestocarrots.com)
Keep reading: What's the best moisturizer for you?
Q. How can I get rid of the deep vertical lines on my upper lip?
A: Those lines are really the only thing I don't like on my face. (Unless you count the spaghetti sauce I discovered on my chin after dinner the other night. I didn't much like that, either.) A three-step approach works well to eliminate the lines, says Deborah Sarnoff, MD, clinical professor of dermatology at New York University Medical Center. Injections of a filler like Juvéderm or Restylane can fill them in. A very small amount of Botox, injected into the sides of the mouth, can prevent the kind of puckering that helps to cause them. Finally, one treatment with a fractional CO2 laser can get rid of them for more than ten years (with three days to a week of redness and swelling and a cost of $1,500 to $4,500).
Keep in mind: If you choose to go this three-pronged route, it's critical that you see a board-certified dermatologist or plastic surgeon experienced in the treatments (too much filler can look unnatural—as I'm sure you've observed—and too much Botox around the mouth can affect your shpeesh).
Keep reading: What are your skin treatment options?
Q: How can I figure out my skin type?
A: It's easy. Wash your face with a cleanser designed for normal skin; rinse well, and pat dry with a soft towel. Now pick up a copy of Alan Bennett's The Uncommon Reader. It's a short, funny book, and if you're undistracted you can probably finish it in about an hour—exactly when your skin will be ready to evaluate. How does it feel? If it's tight, ashy or flaky, your complexion is dry, says Susan Taylor, MD, assistant clinical professor of dermatology at Columbia University. If you're oily only across the forehead, down the nose and on the chin, you've got combination skin; and if you need to blot your whole face with a tissue, you're oily. If your face feels irritated or slightly itchy, you likely have sensitive skin.
Bottom line: Once you've established your skin type, repeat the test four times a year, because your skin probably changes seasonally.
Keep reading: Top 10 skin myths—a dermatologist tells all
Q: Why isn't there a way to get rid of acne immediately and permanently?
A: Hear, hear! We've pretty much figured out how to dissolve fat, prevent wrinkles, shoot people into space (and even bring them back); how hard can it be to get rid of acne? Actually, harder than you'd think, because acne results from a complicated process involving a plugged pore, oil, bacteria and inflammation, and it's also influenced by genetics and hormones, says Katie Rodan, MD, clinical associate professor emeritus of dermatology at Stanford University School of Medicine. A shot of cortisone directly into a pimple reduces inflammation in a day or two, and the oral prescription medicine isotretinoin can give long-lasting results with cystic or severe acne, but the best way to prevent acne is by using a combination of ingredients that address each step in the breakout process, including salicylic acid to disrupt the plug, benzoyl peroxide for protection from bacteria and sulfur for its anti-inflammatory effect. Recent research shows that milk and milk products may aggravate acne, so it might be wise to avoid them.
Bottom line: You can treat the superficial causes topically, but because acne involves genetics, the only permanent solution will involve gene therapy—and we're not there yet.
Keep reading: Val's adult acne cures