Pine trees get a bad rap when it comes to pollen allergies. Often people point to them as the cause of their hay fever or seasonal allergies. Many experts note, however, that few people are actually allergic to pine trees. That view is changing a bit, though, as studies and even patient information is beginning to indicate that while uncommon, pine trees can cause allergic reactions in some people who live in areas densely populated with pine trees.
Facts
More than 35 million Americans have seasonal allergies, according to the American Academy of Allergy, Asthma and Immunology (AAAAI). Tree allergies generally occur in the spring. Pollen and mold spores in the air are commonly the culprits. Hardwood trees---such as ash, alder, oak, birch, elm and maple---are generally the offenders.
Expert Insight
There are different species of pine trees but the pine pollen is basically similar, reports Stanley M. Fineman, M.D., vice president of the American College of Allergy, Asthma and Immunology. "It looks like a little yellow dust," says Fineman. "It is more of an irritant than a true allergen. In general, people don't tend to produce the allergic-type response that they do to regular hardwood."
Pollen counts can be accessed at the National Allergy Bureau, part of the American Academy of Allergy, Asthma and Immunology website.
Symptoms
Typical symptoms of a seasonal allergy (also known as seasonal allergic rhinitis) can include itchy, watery eyes; itchy throat, roof of mouth or ears; sneezing; and a stuffy or runny nose, according to the AAAAI.
Considerations
Pine trees put out huge amounts of pollen, according to David J. Shulan, M.D., vice president of Certified Allergy & Asthma Consultants, in Albany, New York. Pine pollen and grass pollen are in the air at the same time, he said. "A lot of people who are going crazy with their allergies when the pine pollen is out (are reacting to) the grass pollen, which they cannot see."
Misconceptions
Few people are allergic to pine trees compared to the number of people allergic to six or eight other types of trees, says James Seltzer, MD, an allergist and immunologist. "The pollen from a pine tree blows off and typically falls not far from the tree. Most people do not get exposed because it is heavy (pollen) and the pollen grains don't go very far. Consequently, there is not a lot of exposure for many."
However, Seltzer notes that people can get significant allergic symptoms from pine trees. "If you have pine trees in your yard and you or your child is having symptoms then you can advocate for a skin test or blood test for pine. The symptoms can be substantial when people who are sensitized are exposed---the greater the exposure, the more likely they are to be sensitized and develop symptoms."
Conflicting Data
"For a long time, pine pollen has been considered a fairly non-allergenic pollen" because the pollen grain is "too big to really enter the nose and lung easily," says Anne C. Miranowski, M.D., of the Pediatric Lung Center, in Fairfax, Virginia.
Several studies, however, have found it can cause reactions. A study in Spain published in the "Clinical & Experimental Allergy" journal in 2009 titled "Allergenicity and cross-reactivity of pine pollen" concluded, "Pine pollen should be considered as a potential allergenic pollen, especially where this pollen is abundant." These results, Miranowski explains, indicate an allergy to pine should be taken seriously.
One study in Spain, which was published in "Allergy, The European Journal of Allergy and Clinical Immunology" in 1996, and another published in the "Annals of Agricultural and Environmental Medicine" in 2003 support the claim that allergies to pine pollen exist, although not among large numbers of people.
Holiday Myth
The reason Christmas trees bother so many people is because of mold. "They naturally have mold occurring on their bark, trunks and limbs and then when they sit on a truck, that warmer truck environment, encourages more mold growth," Miranowski said. People bring the trees into their homes and think they're allergic to the pollen, when they're allergic to the mold spores. "Even if they were allergic to pine, that is not the time pine trees pollinate."
One of the pleasures of a live Christmas tree or wreath is its scent but that can come at a cost. "I have had quite a few patients who have a problem with live Christmas trees," Shulan says. "It is not the pollen, but the pine scent and sometimes the mold."
References
- American Academy of Allergy, Asthma and Immunology
- Pollinosis due to Australian pine (Casuarina): an aerobiologic and clinical study in southern Spain
- Gastaminza G, et al. Allergenicity and cross-reactivity of pine pollen. Clin Exp Allergy. 2009 Sep;39(9):1438-46.
- Analysis of airborne pollen concentrations in Zagreb, Croatia, 2002.
