Toss expired products. If a product remains sealed and is stored properly, its shelf life can be extended past the due date. But once you open it, the clock starts ticking. "Past expiration, the ingredients meant to suppress bacteria begin to lose their efficacy," says Dr. David Bank.

Take a patch test. If your skin is reacting but you can't pinpoint the cause, get to the doctor's office for a patch test. Dr. Ellen Marmur suggests that the easily irritable conduct their own patch tests on their next beauty-buying trip. "Just try a little of everything on your arm to see if it stings. It doesn't have to sting to be effective."

Even old favorites can let you down. Tried-and-true favorites can eventually elicit an allergic reaction. "The fact that you've used something with impunity for decades does not automatically mean it's off the suspect list," explains Bank.

Less is more. The more products you use, the greater the likelihood that you'll have a reaction. Ultraexpensive creams also tend to pack a multitude of ingredients, says Bank. "They may look, smell, and feel divine, but if you're sensitive, you're better off using a product with fewer ingredients."

Check percentages. If you're allergic to an ingredient, you'll likely have a reaction no matter how much or how little of it is in a product, but if you're simply sensitive, amount matters. "We can sometimes help women by prescribing a milder version of what they're using," says Dr. Marsha Gordon.

PLUS: Check the ingredients. Your sensitive skin can probably be traced back to one of these nine culprit ingredients.

MC RECOMMENDS: Check out our favorite soothing and all-natural products.

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