Doc, I get sick every Christmas and end up missing a few days of work. I take my family out to pick a live tree the weekend after Thanksgiving every year and 1-2 weeks later my asthma flares up. Could I be allergic to my Christmas tree?
The Christmas holiday season brings more than song and joy to asthma and allergy sufferers across the nation. After Thanksgiving, for many families the next order of business is to hunt for the most perfectly shaped, live Christmas tree from their favorite outdoor nursery. In northern parts of America, many evergreen trees are pre-cut and bound together in stacks until time for display. The cold weather allows for some trees to be well preserved despite being cut weeks before being sold. But as they lie in waiting, mold, bacteria, dust and dirt collect on their blades and branches.
A Pile of Evergreens -- Millions of dormant molds lay with them
Live evergreen trees are preferred by many families because of their appearance and fresh, green smell. Unfortunately people allergic to mold may have levels of indoor exposure soar to five times the normal level after bringing in the Christmas tree (as reported by Dr. Philip Hemmers in a study published last year). Microscopic mold spores infiltrate the surfaces of evergreen trees but lay dormant (because of cold temperatures) until they enter the warm environment of your home. After a few days the molds come alive and invisibly fill the air of the home with spores that, to most people, have no harmful effect but to the allergic asthma or hay fever sufferer, the home transforms into a potentially dangerous environment.
"Are mold spores the only problem with live Christmas trees?" my patient asked.
While mold spores pose the greater risk to allergic patients compared to artificial evergreens, other Christmas tree-related triggers may contribute to respiratory problems (these are often overlooked). Evergreen trees are sometimes sprayed with insecticides and other chemicals in order to better preserve them. Evergreens have a natural fragrance enjoyed by many, but risky for some people that have allergic and non-allergic asthma or rhinitis. Furthermore, the blades of evergreen trees may hold large quantities of dust as well as pollen from other trees which may become aerosolized after being brought into the home.
Additional trigger factors include the dusty (and possibly moldy) ornaments, ribbons, stringed lights and other tree accessories that are brought up from the basement or down from the attic. Of course these triggers would also be a problem in the setting of an artificial Christmas tree.
Is the artificial Christmas tree the answer to this problem?
Artificial evergreen trees may greatly reduce the risk of high level mold exposure compared to live trees. But artificial trees may also collect mold and dust over a period of time. However, I don't think you would ever have indoor mold counts catapult as high with artificial trees. Some artificial trees may have oils and other surface residue that may be irritating to the airways but this is not well researched and has not been frequently reported. We (allergists) generally consider artificial Christmas trees a reasonable alternative to the live tree if you are mold allergic.
Finally, my patient asked, "What can I do?"
I offered these tips: