December 14, 2018

Putting up the Christmas tree often marks the start of the holiday season. However, it also often marks the onset of worsening allergy and asthma symptoms such as runny nose, watery eyes, coughing, wheezing, and post nasal drip.

These symptoms and phenomena have been documented as far back as 1930, with the common correlation being live Christmas trees.1  Over the years further tests have been run to pinpoint the cause of the allergic response.2 A 2011 study performed at SUNY Upstate Medical University found a sample of Christmas trees carried approximately 50 types of mold.3 Two-thirds of the mold identified were potential allergens leading to increased nasal and respiratory symptoms. The article also referred to a previous study conducted in 2007 which found a Christmas tree could increase the number of mold spores in an apartment by about 6 times. The mold counts in the air continued to grow while the tree was in the room and did not drop to normal levels until it was taken down.

In 2014, high school students in New Jersey performed a study looking at household air samples taken before and during the holiday season.4 The amount of mold spores doubled when a live Christmas tree was brought into the home.  Artificial Christmas trees also led to increased airborne mold in the home.  There was no significant increase in airborne mold in homes that did not use any type of tree. In participants with underlying asthma and allergies, 42% noted increased symptoms when there was a live tree versus 13% who used an artificial tree.

Other allergy and asthma triggers include terpenes, dust mites, and pest droppings.  Terpenes are chemical compounds that give pine trees their natural scent.  They may also cause irritation in some people. Dust mites accumulate in storage and damp air.  Insects/pests may leave droppings in live trees or artificial Christmas tree storage spaces triggering allergies and asthma.

What can you do to keep your family safe and healthy during the holiday season?

If you have allergies or asthma, here are some tips to help you:

  • Using an artificial tree will reduce the likelihood of allergy or asthma exacerbation. If your tree is in storage it will need to be cleaned before it is put up.
  • Store your artificial tree in sealed plastic (not just its box) to reduce the likelihood of mold or dust forming
  • Use an air purifier
  • Consider removing the tree sooner, as there is evidence to suggest the longer the tree is in the home the worse the problem will get
  • For live trees and artificial trees: take the tree outside and thoroughly rinse it off with a hose (then leave the tree somewhere warm to dry for a couple of days before bringing it into the house) or use an air compressor to blow off as much debris as possible
  • A 1:20 solution of bleach to water will help to kill any existing growth on the tree. If you have pets that may chew on the tree you will want to avoid this

For allergy relief during the holiday season, contact the Allergy & Asthma Center at 800-778-9923 or schedule an appointment online.