1. Trigger: Christmas trees That’s right—the one and only, the centerpiece of all things Christmas, that perfect fir you found hiding in the lot of freshly-cut trees that’s now twinkling with the lights you spent hours untangling–may be to blame for your stuffy nose, watery eyes and rash-y skin. “Mold is the biggest problem with live Christmas trees,” says Marilyn Li, MD, an asthma and allergy specialist with the Los Angeles County + University of Southern California Medical Center. “Often, they are cut in advance and kept in humid environments, promoting spore growth.” Within just two weeks of bringing a tree into your home, indoor mold counts can increase significantly, according to one study. Other tree-related allergens: The sap contains terpene and other substances that can irritate skin and mucous membranes; and pollen stuck to the tree may be released inside and lead to reactions, adds Nathanael S. Horne, MD, clinical assistant professor of medicine at NYU school of Medicine and fellow of the American Academy of Allergy, Asthma & Immunology. What about the artificial versions? They could harbor dust and mold from their time in storage, also triggering allergies. Prevent it: Slip on gloves and wear long sleeves when handling your fresh tree to avoid the sap coming into contact with your skin. Before schlepping your tree inside, give it a good shake (or a blast with a leaf blower) and spray it down with a garden hose (especially the trunk) to help remove some of the pollen and mold, suggests Horne. Then sit the stump in a bucket of water and let the tree dry for few days on a covered porch or in a garage. For an allergen-free fake tree, give it a good wipe-down before decorating with lights and ornaments. MORE: 4 Holiday Health Busters 
  2. Trigger: Decorations For eleven months out of the year, all your ornaments, lights, and holiday chotchkes sit stored out of sight, collecting dust and maybe developing mold. When the boxes of red, green, and gold goodies come out, the symphony of sneezing, coughing and nose-blowing commences. Prevent it: Before decking your halls, mantels, windows and trees, wipe down each item thoroughly; when it’s time to repack, store your holiday trimming in airtight containers, and in a dry spot if possible. Also, go easy on the spray snow—you may love the look of frosted windows, but any aerosolized chemical can cause irritant reactions in the eyes, nose or lungs of a sensitive person, says Horne. 
 
  3. Trigger: Homemade pie The fact that she makes “Why aren’t you pregnant yet?” the topic of Christmas dinner is enough to make you break out in hives–but the nuts that she baked into her dessert crust could be to blame, too. If you have food allergies, the holidays in particular are a ripe time for reactions, simply because you’re around so. much. food. The most common food allergens are milk, eggs, soy, fish, shellfish, peanuts, tree nuts, and wheat. “Of those, peanuts and tree nuts will most often make it into holiday dishes without people knowing, and have the potential to cause severe reactions,” says Horne. Prevent it: It’s a good idea to let your holiday host know about your food allergies; it’s important to ask about the ingredients in each dish; and it’s very nice to volunteer to bring something that’s safe for you, and shareable with others. But what’s crucial is to be prepared with an epinephrine auto-injector (Epi Pen), an emergency dose of antihistamine, and an inhaler if you have asthma—just in case, adds Li, director of the USC Breathmobile, a pediatric clinic that travels to schools and provides ongoing asthma and allergy care to children. Learn which foods and recipes are unexpected sources of allergens at FoodAllergy.org and AAAAI.org.
  MORE: How To Prevent Holiday Weight Gain
  4. Trigger: Cocktails You raise a glass to your loved ones, your boss and colleagues, friends and neighbors, and even the strangers sitting next to you at a bar. There’s lots of cheers-ing this time of year, but be mindful of what you’re using to toast. Some people may experience mild wheezing or other symptoms from the sulfites in wine, for example, and certain alcoholic concoctions contain major food allergens. 
 Prevent it: There aren’t good tests for sulfite sensitivity, but your reaction to dried fruit—high in this sulfur-based preservative—could be an indicator, says Horne. Pay attention if you have asthma, as sulfites can trigger symptoms. Maraschino cherries contain small amounts of sulfites, as well. Stick with organic wine for a sulfite-free sip. Other triggers to be aware of: Tree nuts may be found specialty beers, particularly seasonal ales; milk is in Irish crème and white chocolate liqueurs; and egg whites may be used to add froth to specialty drinks. 
MORE: Low-Calorie Holiday Treats
  5. Trigger: Poinsettia This festive plant is a member of the rubber tree family and contains compounds similar to those found in latex, so stay away if you have a latex allergy. Certain groups of people—such as healthcare workers and people with spina bifida who have had numerous surgeries—are more likely to be allergic to latex, says Li, and one study showed that 40% of latex-allergic individuals were also allergic to poinsettias. Prevent it: If you have a latex allergy, keep the iconic plant out of your house—not only can it give you a rash if you touch it, but inhaling the allergen can lead to serious respiratory problems, like shortness of breath and wheezing. MORE: 5 Holiday Pet Dangers
  6. Trigger: Smelly stuff Pine-infused potpourri, dessert-scented candles, cinnamon air sprays—while they will make your house smell like Christmas, they can irritate the nose and throats of allergy-sensitive people. “Candles in particular are an increasingly recognized source of indoor air pollution,” says Horne. “The same is true for air sprays and other types of air fresheners—they can release many different types of noxious compounds, which can generate adverse reactions in sensitive patients.” Prevent it: If skipping the scents feels Grinch-like, try making your own potpourri with cinnamon sticks and cloves so you know what’s in the mixture, says Horne. And choose candles made of soy or beeswax, suggests Li. There’s not much smell, but you can still enjoy the warm glow. By the way, fireplaces are an absolute no-no for asthmatic patients—the ash and smoke can trigger an attack, so keep the log unlit. 
 MORE: Attack Allergies With Yoga
  7. Trigger: Shopping Stress doesn’t cause allergies or asthma by itself, but it can hinder your immune system and be a trigger for asthma attacks, says Horne. Chemicals released by the body during stressful times can cause the muscles around your airways to tighten, making it difficult to breathe. Prevent it: All the deep breathing in the world probably can’t calm the chaos that comes with the season, but what you can do is make sure you take the steps to stay healthy: Stick to your controller medication regimen and get a flu shot, advises Li. 
 MORE: How To Have Stress-Free Holidays