Christmas tree allergy
n. Allergy symptoms caused by a decaying Christmas tree inside a house or apartment.
Allergists have long suspected that live Christmas trees are the culprits behind some folks' runny, itchy noses during the holidays — and now one doctor believes he has proof. …

Santilli placed a live Christmas tree inside an intern's apartment and took air samples for two weeks. (Santilli keeps his Christmas tree on a porch until Christmas Eve.)

For the first three days, the mold counts inside the apartment hovered around 800 spores per cubic meter of air, compared with a normal range of 500 to 700 spores per cubic meter. But by day 14, the mold count had skyrocketed to 5,000 spores per cubic meter. …

Although the medical community has long known about "Christmas tree allergy," there has been some debate over what causes the sneezing, runny noses and watery eyes — pollen or mold.
—Linda Shrieves, “Christmas tress may be adding to your holiday sniffles,” Orlando Sentinel, November 22, 2007
Wyse published the first research on Christmas tree allergy. Aromatic resins in the yuletide tree, he learned, could cause severe asthmatic attacks in some people, while the release of tree pollens could cause milder reactions.

"I think he was the first person to document it," Lackner said, "which he always laughs about with me because he's Jewish."
—Naomi Powell, “A lifetime of Wyse choices,” Guelph Mercury, July 19, 2003
1981 (earliest)
For some allergy-prone holiday revelers, the air holds more than the feeling of Christmas — health officials say Christmas trees also contribute to air pollution.

''It happens every year about this time,'' said Glen Castleberry of the Tulsa City-County Health Department's air quality division.
''We call it the Christmas tree allergy,'' said Tulsa allergy specialist Dr. Leon Horowitz.
—“National News Briefs,” United Press International, December 17, 1981