Hay fever, otherwise known as seasonal allergic rhinitis or pollinosis, is an allergic reaction to weed, tree, and/or grass pollen that gets into the upper respiratory passages including the nose, sinuses, throat, lungs, and also the eyes.
Hay fever is the most common of all the allergic diseases, affecting about 15 per cent of the population. During the beautiful seasons of spring and fall, an estimated 36 million Americans will be suffering from hay-fever symptoms caused by pollen allergies. Symptoms usually appear in childhood and then begin to lessen by the age of 30 or 40.
Symptoms of seasonal allergic rhinitis are caused when a person's immune system mistakenly identifies pollen as an intruder and produces antibodies specific to that allergen. During subsequent exposure and inhalation of the pollen into the nose or lungs, a series of immunologic reactions occur, resulting in the release of histamine and other chemical mediators of inflammation. These mediators are responsible for the inflammatory symptoms of allergy. And so with the change of seasons, both children and adults begin to exhibit symptoms of pollen allergies- sneezing, runny noses, nasal congestion, watery eyes, and itchy nose, eyes, ears, and throat. Exposure to pollen can also result in seasonal asthma.
Which pollens are responsible?
The particular pollens responsible for seasonal allergy symptoms are the extremely light and airborne weed, tree, and grass pollens. Under ordinary circumstances, gentle breezes carry these microscopic male reproductive cells to female plants during the season of pollination. The problem begins when these pollens, destined to land on a female plant, are breathed into the nose or lungs, or are exposed to the eyes of a pollen allergic individual. As opposed to the weed, tree, and grass pollens, flowering plants generally do not cause problems for the pollen allergic individual because their pollen grains are too heavy to remain airborne. They depend on insects, not the wind, to carry their heavy, waxy pollen granules from plant to plant.
Several factors affect the timing and intensity of the pollen season. The time when a given species of plant pollinates is determined by the relative length of the days and nights. In general, the same plant will pollinate earlier in the south and later in the north. Weather conditions, especially rainfall or lack thereof, plays a role in how much pollen a plant produces. This is thought to be the primary determining factor contributing to the wide fluctuation in pollen counts from year to year.
When do plants pollinate?
Trees typically begin to pollinate in the late winter or early spring and reach their peak pollen production in early and mid spring. But, as the tree pollen counts moderate and diminish, those with spring allergies usually do not get a much of an allergy break, as the grasses start to pollinate on the heels of the tree pollen season. Grass pollination peaks in late spring and early summer but can continue through the summer season. Ragweed, the main culprit of the weed family in most of the United States, begins to pollinate in mid-August and can continue though October.
Some of the most common trees which pollinate in the early spring to late spring include oak, birch, cedar, cypress, elm, hickory maple, poplar, sycamore, and walnut. From late spring through the summer, the allergenic grasses might include Bermuda, timothy, sweet vernal, orchard, blue, red top, and rye. The most common weeds, whose pollinating season is from late summer to mid autumn, are ragweed, pigweed, cockleweed, Russian thistle, sagebrush, and tumbleweed. However, some trees, grasses, and weeds, are particular to certain geographic area of the United States. For example, in the southwest, western cedar pollen is a major cause of problems, yet this tree and its pollen is not found in New England.
What is the value of pollen counts?
Pollen counts can be a valuable tool for allergy sufferers during the pollen season. These counts can help allergy sufferers plan outdoor activities on days and times when pollen is least likely to cause problems and to avoid being outdoors on days when the count is extremely high. Local pollen counts are usually available for most large metropolitan areas and can be accessed on the home page of this website.
How can pollen allergies be treated?
A common misconception is the notion that if I or my child is allergic to oak tree pollen and I have oak trees in my yard, it would be helpful to cut them down. Or similarly, if I or my child is allergic to the pollen of bermuda grass and my lawn is bermuda, I need to remove it, or even move. These conclusions are incorrect. It matters not whether the source of the pollen is in your yard or fifty miles away.
The pollen one breathes may have come from anywhere, even a location hundreds of miles away. A sobering statistic: A single ragweed plant can produce approximately a billion pollen grains per season and can travel up to 400 miles from its source!
Even though pollen is an airborne allergen which is impossible to totally avoid, there are a number of things that one can do to minimize exposure to pollen.
In your home, keep all windows closed and run your central air conditioning or a window unit for air circulation and filtration. Replace your furnace filters or wash electrostatic filters regularly to help clean pollen out of the air. It can also be helpful to use vent filters on the room vents to catch any pollen which might not have been removed by the furnace filter. Run a HEPA air cleaner in the bedroom to help eliminate the pollen that makes its way into the home.
If possible, try to avoid outdoor activities which will cause the pollen on the ground to become airborne, such as mowing the lawn, or raking or blowing leaves. If you must work outdoors, especially if the pollen count is extremely high, wear a pollen mask. Also, it is a good idea to take a shower when you come inside to remove pollen from your hair and skin. Also, irrigate your nose to remove pollen from your nasal passages.
As with any allergy which cannot be “cured” by total avoidance of the allergen(s), the best treatment option for season pollen allergies is a comprehensive approach, which includes environmental control (minimizing exposure to whatever degree possible), pharmacotherapy (the use of medicine), and possibly immunotherapy ( desensitization to the allergens). Your allergist will play the key role in recommending the best therapy for you or your child with the goal of making the spring and fall glorious seasons once again.
