Tree Pollen Triggers Asthma

by John Bottrell Health Professional

Spring can be a difficult time for asthmatics, especially those of us with outdoor allergies. When the trees start pollinating, you can expect allergic asthmatics to start suffering from itchy and watery eyes, nasal congestion, runny nose, scratchy throat and wheezes.

So what is tree pollen and why does it bother asthmatics? Many websites answer this question, but I think the simplest definition comes from

Pollen grains are a fine dust that plants typically release in spring. They carry the plant's male DNA from the stamen (the male part of the plant), to the pistil (the female
part of the plant), in the process known as pollination. Pollination makes fertilization and reproduction possible in plants. Tree pollen is simply the pollen produced by trees. It is a common allergen, though there are only about 100 species of trees that cause reactions in those who suffer from tree pollen allergies. Tree pollen allergies account for about 20 percent of hay fever symptoms as well.

When you have early spring allergies, it's usually tree pollen that's the culprit, as trees are known to pollinate earlier than grass. According to the National Institute of Environmental Health Sciences (NIEHS), trees can start pollinating as early as January in Southern states.

According to most experts, the following are the biggest culprits:

  • Oak

  • Western red cedar

  • Maple

  • Elm

  • Birch

  • Ash

  • Cypress

  • Walnut

  • Hickory

  • Poplar

Tree pollen is microscopic, so you can't see it. The pollen is generally oval or circular in shape, and is the perfect size to be easily inhaled into your respiratory tract. Here it is treated as an enemy by those with allergies, and your immune systems treats it the same way it would an invading bacteria or virus.

When your body is first exposed to tree pollen, your immune system develops antibodies specifically designed to recognize this "perceived enemy" the next time you are exposed to it. Every subsequent exposure such as every spring--your body reacts to tree pollen and goes to all-out war with it.

Tissue lining your respiratory tract and eyes becomes inflamed, and this is what causes your tree pollen allergy symptoms. Your immune system thinks it's doing something good, yet it's actually an unnecessary response to an organism that is harmless to 90 percent of people.

According to, the website of the New York Allergy and Sinus Centers (NYASC):

"Each spring microscopic oval and circular tree pollen particles are released to hitch a ride on currents of air. Their mission is to fertilize other trees of the same species. Insects do this for some trees, but for most the wind is relied on. Small, dry and light, pollen granules have been known to travel as far as 400 miles out to sea and up to two miles high in the air. Because the airborne pollens can travel so far, it does little good to remove the offending tree. Pollen can drift in from miles away."

Emphasis was added by me to show that no matter what you do, you cannot hide from tree pollen. So what can you do about tree pollen allergies?

There are some medicinal options, which you can read about here. I like to use Claritin in the morning because it's a non-drowsy antihistamine, and if I need to, I use Benadryl at bedtime. I also have a prescription for Singulair, but it hasn't seemed to do much good for me.

Some experts recommend keeping track of pollen counts in your area by checking out websites like I think this site is neat because it tells you the pollen count with a brief discussion of why it's high or low. It gives you an idea of what to expect today and the next couple of days.

According to Wisegeek, a pollen count is a measure of pollen grains in a cubic foot of air. The recommendation is that tree pollen sufferers stay indoors when pollen counts are high. Pollen counts are generally higher between 5 and 10 a.m., so mornings are not the best time to be doing anything outdoors.

If pollen counts in your area are high, stay indoors with your windows shut. If it's too hot, turn on the air conditioner.

Personally, though, I'm not one to pay much attention to pollen counts. My goal in life is to live as normal a life as I can, and most people don't check pollen counts each morning. I also love a springtime breeze, and most people open windows when it's nice out.

If you're like me and suffer from springtime allergies, you are not alone. NYASC notes that over 35 million people suffer from springtime allergies, and 5 million of these (about 15 percent) suffer from tree pollen allergies.

John Bottrell
Meet Our Writer
John Bottrell

John Bottrell is a registered Respiratory Therapist. He wrote for HealthCentral as a health professional for Asthma and Chronic Obstructive Pulmonary Disease (COPD).