Ho! Ho! Ho! Christmas Trees as Allergens

The American Christmas Tree Association indicates that 95 million American households will have Christmas trees in 2017—that represents 76% of all homes. This tradition dates back to Queen Victoria in England. Only 19% of Christmas trees will be harvested live.

Health care providers should be aware that Christmas trees have been associated with allergic contact dermatitis and allergy, and they should be on the lookout for these problems if patients report with rash or other allergic manifestations. This issue is covered in a case report and review in the December issue of journalContact Dermatitis.

The authors, researchers from the Department of Dermatology and Allergy at the University of Copenhagen in Denmark, attribute most allergic problems to colphonium. Colophonium (also called colophony) is a sticky substance in evergreen trees from the familyPinaceae,which includes pine and spruce. Many people don't know that manufacturers of adhesives, cosmetics, and toiletries use colophonium in some products. For example, colophonium is used as an anti-slippage covering on some balls used in sports, often included in tennis racquet parts, and it's a component of violin bow rosin. It's also in dental cement, high-quality glossy paper, match tips, and many topical medications.

Recently published data indicate that approximately 2% of adolescents are allergic to this compound. In many countries, it is ranked number 1 in the top 10 allergens, and it's a very common source of occupational contact dermatitis.

Patients who are allergic to colophonium often develop contact dermatitis on exposed areas, and it often spreads from the hands and forearms to the face and neck. Since Christmas trees are rich with colophonium, individuals who decorate the tree may develop a rash on the hands.

When retail health providers suspect colophonium allergy, they may try prescribing a mild hydrocortisone cream and antiprurtics to reduce itch. In this article, the authors noted that the patient did not respond to mild hydrocortisone cream and oral antihistamines. Oral prednisone 25 mg was prescribed for 3 days but severe dermatitis persisted. The therapy was continued for another 4 days. Resolution of the patient's problem was gradual and the dermatologist prescribed topical hydrocortisone 17-butyrate cream, which eventually resulted in complete resolution of the dermatitis.

It is possible to order patch testing to determine if patients are allergic to colophonium.The Contact Allergen Databaselists products that contain colophonium. Retail health care providers should note that Christmas trees can sometimes cause respiratory symptoms because the colophonium is airborne.

Reference

Gether L, Gyldenløve M, Thyssen JP. Christmas tree dermatitis caused by colophonium allergy.Contact Dermatitis. 2017;77(6):412-414.

Hamstra A, Jacob SE. A review of colophonium.The Dermatologist.2015. Available at https://www.the-dermatologist.com/content/review-colophonium. Accessed December 19, 2017.