Experts say the phenomena happens, in part, because we spend a lot of time indoors -- visiting people's houses, meeting unfamiliar pets, and we're surrounded by dusty decorations and live trees.
Those trees might look beautiful and smell good but they can also release mold spores into the air, potentially triggering an allergic reaction.
Issue: Moldy Trees
Allergy specialist Dr. Katie Marks-Cogan of South Bay Allergy and Asthma says live Christmas trees build up mold because they're cut and stored for a few months prior to sale. Marks-Cogan says going artificial can help, but even fake foliage can accumulate dust and mold.
Tip: Rinse Off Real and Artificial Trees
Hose down real and artificial trees before bringing them inside to help reduce or eliminate existing mold and dust. Allow trees to dry out fully before bringing inside.
Issue: Dusty Decorations
Allergy symptoms can also be caused by decorations that have collected dust while sitting on the shelf.
Tip: Use Airtight Storage
Minimize dust exposure by storing ornaments, wreaths, candles and other decorations in airtight, dry containers.
Issue: "Holiday Effect" Symptoms
It's not uncommon for "someone to temporarily lose tolerance to an allergen that they've been consistently exposed to in the past," according to Marks-Cogan. Allergists call it the "Holiday Effect." It can happen, for example, when a college student comes home on break and suddenly seems to be allergic to the family dog.
Tip: Prepare for Unexpected Symptoms
If you're planning on traveling this holiday season, plan on packing a few over-the-counter allergy medications so you're ready to treat surprise symptoms.