Grass Pollen Season: Some Common Misconceptions

James Thompson, MD Health Pro April 27, 2009
  • "Doc, I think I'm allergic to cottonwood tree. Every summer I start sneezing my head off when those "cotton things" start floating around in the air."

     

    Every year in May or June a few people ask me about cottonwood allergy after noticing their eye and nasal symptoms escalate as the cottonwood tree molts its seedlings. But this is a common misconception. In March and April (primarily in northern states of America) cottonwood tree pollen fills the air, along with the pollen of many other types of trees. About two months later cottonwood trees begin casting off their seedlings. By this time pollen season for most trees in the northern states is over. So why do so many people mistakenly blame the cottonwood tree for their sinus allergy problems?

     

    Cottonwood seedlings- An Innocent Bystander

    For most of the Midwest and Northeastern states grass season begins in late spring and goes to or into July. The months of May and June are considered the peak months when grass pollen infiltrates the air in invisible clouds, especially in the early morning hours. Cottonwood tree happens to molt at the same time grass pollen season is peaking. This means the sneezing, runny nose, itchy and watery eyes may only get associated with what the eyes can see (cottonwood seedlings). The tiny microscopic grass pollen grains are not visible to the naked eye.

     

     

    The cottonwood seedlings are not pollen. They are much too big and bulky to get far enough up the nose to cause allergy. These seedlings are innocent bystanders. They do not cause allergic symptoms although they may be annoying to many people because the smaller parts of the floaters that break off may tickle the nose.

     

    Cottonwood seedlings- Chicago, June 2008

     

    Another innocent bystander: Roses- "Rose Fever"

    Summer allergy problems have also been blamed on plants that bloom in May or June and include roses. For this reason seasonal spring and summer allergies have often been referred to as "rose fever". But again, the pollen from roses is much larger than the pollen from wind pollinated plants (trees and grasses). Roses and many other flowering plants are pollinated by insects such as bees and butterflies. The heavier pollen from flowering plants tends to drop straight down from their anthers (the male reproductive structures) due to gravity. The abundance, buoyancy and smaller size of pollen from grasses and trees allow the wind to carry pollen clouds hundreds of miles. This explains why many city dwellers also suffer from seasonal allergies despite living in areas where grass and trees may be sparse.

     

    Some roses when brought indoors may give off a strong fragrance which may cause nasal irritation. But rose pollen is not an allergic threat whether indoor or out.

     

    What about the term "Hay Fever"?

    Once again a commonly used term for seasonal allergy represents a false association. Hay does not directly cause allergy (nor is any fever involved). Moldy hay can be a problem because of the allergic mold that may collect in it but hay fever was originally meant to identify people with suspected grass allergy. The term became popular in the 1800's when it was noted that upper respiratory symptoms were associated with a time when field hay was being harvested. Yes, another example of "guilt by association".

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    Currently "hay fever" is used interchangeably with "allergic rhinitis" and refers to people that may suffer from seasonal or perennial (year round) nasal and eye allergy problems.

     

    What Can You Do To Prepare For Grass Season?

    Review tips previously posted by clicking this link: (Allergy Tips)

     

    Follow pollen counts in your area by clicking here: (pollen counts)