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Candles

You can’t be allergic to essential oils—which make candles smell like autumn leaves or dune grass—but their odors can inflame your nasal cavities, says Dr. Wedner. “People with nasal allergies have a natural increased sensitivity, so they’re likely to get a runny nose or watery eyes around candles,” he says. “To the person with the sensitive nose, it’s no different than cigarette smoke.”

What to do: If you’re very sensitive, avoid candles altogether. But if you love the smell and want to use them at home, buy candles that have few ingredients and feature just one scent, like pumpkin. By a process of elimination, you may be able to pinpoint which scent or ingredient bothers you. If you have a bad reaction to a scented candle, getting some fresh air should make you feel better.

Next: Perfume