What it is: Hormonal fluctuations boost the sebaceous glands' oil production, increasing the likelihood that pores get plugged with oil, dead cells and bacteria. Stress, too, may influence the release of hormones that affect the skin.
Symptoms: Whiteheads, blackheads, cysts or pimples—plugged pores—on your face, neck, chest, back, shoulders or upper arms.
How to treat it: Keep your hands off your face and wash gently—squeezing and vigorous scrubbing can exacerbate acne. Consult a dermatologist. "Teen acne responds to drying gels, but adult skin needs a gentler remedy," says Polisky, who advises older patients to use Rezamid, a topical cream and cover-up that's less drying than benzoyl peroxide. Certain oral contraceptives have been proven to help control acne, and a new drug, Nicomide, is promising.
Product recommendations: Aveeno Clear Complexion Foaming Cleanser, $7, and L'Oréal Pure Zone Skin Relief Oil-Free moisturizer, $8, contain salicylic acid, a gentle beta-hydroxy acid that helps prevent breakouts.
Declutter your life! Our March issue features a complete guide to streamlining your life, from Peter Walsh's 30-Day Organization Challenge to innovative ways to clear your mind. Plus, go behind the scenes of Oprah's yard sale and find out how you can improve the world with a simple "hello."