Some of our favorite winter things can also trigger reactions. Allergic Living gives the low-down on what to watch out for.
1. Scented Candles
The thought of cinnamon or vanilla wafting through the house may be appealing, but scented candles smell of big trouble for those with allergies or chemical sensitivities.
“People who have environmental allergies such as to pollen or pets develop very sensitive inflamed nasal tissue which is hyper-reactive,” explains Canadian allergist Dr. Antony Ham Pong. “These tissues then react more strongly to scents, and act as if they are allergens and mimic an allergic reaction.”
Plus, consider whether soy-allergic guests will be visiting before you light up that soy wax candle. While most are made from hydrogenated oil, which won’t cause an inhalant reaction, your soy-allergic guest or her child may feel uncomfortable knowing that a soy product is wafting through the air.
Advice: Use unscented, beeswax candles or opt instead for trendy fairy light strings for table décor or wreaths.
2. Festive Spores
If you have environmental allergies, a pine or cedar dominating the living room can bring you to sneezes and tears (or worse). Allergists warn at this time of year about “Rudolph the Reindeer Syndrome,” literally a reaction to the Christmas tree.
“Allergic reactions can occur to any pollen from the pine cones, or to mold in the bark of the tree,” Dr. Ham Pong notes. He says the tree’s resin can also cause “either eczema from contact with the skin, or nasal symptoms due to the scent.”
Mold is the biggest issue – some studies suggest household mold counts can increase as much as 10 times with a cut tree in the home. But an artificial tree can also harbor mold if it was stored in a damp basement.
Advice: Reduce the allergen load of a fresh-cut tree with a good blow-out – either taking it home on the roof of your car or subjecting it to a leaf blower on your front lawn. This gets rid of pollen grains and some mold. If mold is an asthma trigger, the Asthma and Allergy Foundation of America  additionally suggests wiping around the tree’s trunk with a solution of 1 part bleach to 20 parts of lukewarm water. Also, wear gloves when moving a tree or boughs to avoid contact with the sap.
Or: Opt instead for a nice faux tree. Just be sure to enclose it plastic post-season, and store it in a dry spot.
3. Up in Smoke
Watch out for a roaring wood fire when visiting. As certified asthma educator Jo-Anne St. Vincent has explained in Allergic Living  magazine, that can expose those with asthma or allergies to a variety of environmental triggers, including smoke and mold.
If visiting friends in a home with a trendy enclosed gas fireplace, that’s a safer bet. But even then don’t linger close by. Vincent says gas-burning fireplaces still emit nitrogen oxide, which can increase inflammation of the airways.
While manufactured fireplace logs used to be infamous for off-gassing toxic chemicals (since industrial waste was part of their composition), today these logs are much more environmentally friendly. There are still two problems though from an allergy/asthma perspective:
a) smoke, no matter how “green” still irritates sensitive airways.
b) Nut allergy  concerns. Several brands make “crackling” fire logs, and they use walnut or other nut shells to achieve the sound while burning. It’s wise to avoid putting such proteins into the air around a nut-allergic individual.
Advice: Best of all is to ask close family to forgo the fire in the living room, if that’s to be the main party room.
4. Knit Softly
A sweater is a classic seasonal present. But watch which knit you pick. For instance, put one of those great “to look at” rough knits against sensitive skin and your gift recipient will be itching to get it off – now! And it’s not just the person with an allergy-prone hide: “Wool is the prickliest natural fiber known, as sheep hair has barbs,” says Dr. Ham Pong.
Many people get itching and redness when their skin is directly exposed to the fabric. For those with eczema, the effects are magnified. Related to wool is lanolin, which is made from sheep fat. The emollient can cause allergic contact dermatitis and eczema flare-ups.
Advice: Check labels carefully to avoid wools that bother your gift-getter. Or go upscale and purchase alpaca, which is highly allergy-friendly and gorgeous.
5. Bathing in Itch
There’s a woman on your gift list who you don’t know to well. Naturally, you head to the bath products because, what woman doesn’t love those? Well, that depends. If she has nut allergy, she won’t love you for the macadamia-based skin-care product.
If she has contact dermatitis or other skin sensitivity, Allergic Living columnist Dr. Sandra Skotnicki, a dermatologist, says to avoid fragranced products. She also counsels opting for facial and body soaps that are mild and unscented.
Dr. Skotnicki says: “Fragrance is still the number one cause of allergic contact dermatitis to toiletry products, with an incidence of about 4 per cent within the North American population.”
Advice: What smells great in the store can be highly irritating to the skin, and the airways for those with asthma. Look for unscented products rather than “hypoallergenic”. The latter is widely used, but many so-called “hypoallergenic” products contain fragrance.
Next: Food and Drink Tips
FOOD & DRINK
6. Think: What’s in That Drink?
When uncle pulls out his coveted single malt Scotch, surprisingly those in the room with celiac disease can also hoist a glass. While Scotch and rye whiskeys are derived from fermented grains, the gluten is thoroughly removed during the thorough distillation process of whiskeys. Wines and ports are grape-based and also generally gluten-free. (See more on gluten-free drinks here .)
The nut-allergic also have to be mindful around alcohol (though wine is generally safe). Oddly, despite its name, the liqueur Amaretto usually does not contain almonds, but check with a manufacturer to be certain of a specific brand is safe.
Advice: Be on the lookout for mixed drinks. Celiacs and the allergic alike must watch out for gluten or allergens in drink blends. When it comes to alcohol, the tree-nut allergic have to be mindful since some liqueurs (e.g. Frangelico and Kahana Royale) and brands of gin can contain nuts. And did you know that Southern Comfort contains nut derivatives?
7. Frosty Around the Food
It’s no secret that those with food allergies and celiac disease have to keep their guard up over the holidays. But even if you’ve explained your allergies and the concept of cross-contamination – remember that a favorite auntie doesn’t live with these restrictions daily and may mess up. Ingratiate yourself into the kitchen, ask to read labels and ask what’s in a favorite recipe..
Advice: here are a few suspect foods to be on the lookout for this time of year:
* pre-basted turkey – ingredients can include soy or gluten or milk. (Speak to the hosts about label-reading soonest.)
* stuffing: gluten and nut alert!
* gravy: If the hostess is at all hazy on her many ingredients, take a pass.
* Hanukkah menus can be tricky to navigate. Latkes usually contain egg and wheat and often dairy (cheese latkes are popular). Consider contributing our allergy-friendly, gluten-free latkes .
* Hanukkah gelt ingredients can include dairy and nuts. Best to provide allergy-friendly gelt. 
* dessert: the wisest course is to offer to bring it, since desserts are potential minefield of nuts, gluten, dairy or egg. If store-bought, soy is often an ingredient, used as an emulsifier.
8. Holiday Stress
We all “think” we’re having fun over the holidays, but sometimes all the preparations, travel or entertaining, plus late nights can add up to a lot of stress. And that, warns the American Academy of Allergy, Asthma and Immunology, can have a detrimental impact on your immune system. The AAAAI also notes the risk for asthmatics because as family gathers, so does the likelihood that someone is there spreading viral illness.
Advice: Watch that you’re getting a little decompress time, make sure in the chaos of a busy house that you or your child is taking your usual asthma or allergy medications.
Next: Food Allergy Tips
Holiday Food Allergy Tips
by Laurie Harada,
Executive director of Food Allergy Canada 
• Teach young children to say “no thanks” to unapproved foods. ’Tis the season of sharing and well-meaning adults and children, who will offer food without consulting the parent. Through role play, teach your child to say “no thanks” politely to anything that you have not approved.
• Bring goodies so your child doesn’t feel left out. Involve him in selecting or making a really special (read “junky”) treat. A pack of raisins won’t measure up when all the other kids get Santa Claus holiday cupcakes.
• Be careful of what others don’t know. Friends and relatives may know how to avoid obvious allergens such as peanuts and nuts in baked goods, while they may forget about nut extracts or that butter is, in fact, made from milk. They might not be aware of the risks of cross-contamination through shared utensils. They also may not be label savvy, and not understand the importance of “may contain” warnings.
• Be a role model; children learn from our behavior. Though I’ve instinctively wanted to remove all shrimp rings and nut trays, I came to realize that my son had to learn how to avoid food allergens as they will be around him in everyday life, not just during the holidays. We’ve taught him to avoid buffets, scrutinize food labels, and wash his hands regularly. Since he’s now in his teens, he knows to make his own inquiries.
• Offer to bring a dish which is safe for your child and can be enjoyed by others. At our neighborhood New Year’s Eve potluck, my family takes care of the kids’ and teens’ meal – pizza, veggies, and potato chips – a popular treat.