Seasonal allergy, or hayfever, is a common disorder afflicting between five and ten precent of the population. The Allergy Group is keenly interested in this group.
At its mild stage, seasonal allergy can be easily controllable by avoiding common pollen sources, such as grass mowing and conventional antihistamines. On the other hand, moderate to severe seasonal allergies can be miserable, interfering with normally enjoyable outdoor activities and interrupting proper sleep patterns. This can lead to fatigue and poor concentration with a falloff in school and work performance.
In contrast to other forms of “allergy” such as idiopathic urticaria (hives) or intrinsic non-allergic asthma, seasonal allergic rhinitis is due to the area’s seasonal pollen patterns. This can be accurately determined 90 percent of the time with direct skin testing or a specific blood test termed RAST (radioallergosorbent test).
Before focusing on allergic rhinitis, it is advisable to understand the mechanism of allergy. An allergy is an abnormal antibody response to an external protein termed an allergen. The IgE antibody is fixed to the surface of mast cells in tissue such as the respiratory tract or basophiles which circulate in the blood stream. When a specific allergen is absorbed through the respiratory membrane, the allergen combines with two surface antibodies. This triggers the release of chemical mediators such as histamine that react on the nerves and blood vessels to produce tissue swelling and irritation. The allergy sufferer then experiences nasal congestion, profuse watery drainage, sneezing and eye inflammation—in other words, hayfever. The allergens, which are inhaled, are numerous, greatly magnifying a patient’s symptoms.
To treat the hayfever patient, the general physician diagnoses the problem as allergy versus nasal or sinus infection and prescribes appropriate medication. The medication includes antihistamines (Allegra, Astelin, Clarinex, or Zyrtec), decongestant, pseudoephedrine, topical corticosteroids (Flonase, Nasacort, Nasalide, Nasonex, Rhinocort), or, in severe cases, an injection of cortisone for short-term relief.
Unfortunately, in spite of these fairly recent treatments made available over the last 10-15 years, many seasonal rhinitis patients do not respond and require a specialty evaluation by a trained allergist*. The allergist’s office nurse performs direct skin testing to reproduce the allergic reactions topically to the suspected seasonal pollens and perhaps mold spores. The testing results, which take an hour to perform, are then correlated with the patient’s symptoms. An allergy extract of the reacting pollens is formulated by the allergist to eliminate the allergy and the troubling symptoms. This treatment is termed immunotherapy.**
It is essential that the allergist be familiar with allergic pollinating plants in his area of practice. Southwest Idaho is located in the northern aspect of the Great Basin of North America. The Great Basin is an arid region consisting of grasslands and sagebrush, with trees such as cottonwood and willows in the river corridors and conifers in the mountains. With agriculture with extensive irrigation, the flora of this region has changed drastically over the last 100 years, introducing new trees, weeds, and crops that have significant allergic potential.
Through pollen sampling during the spring (April 1st) to fall (October 31st), the pollen of this region’s allergic plants can be identified. Important allergic plants produce wind-dispersed pollen that adheres to ova resulting in plant seeds and reproduction. A compact sphere of protein and some carbohydrate, this pollen ranges in size from 20-150 microns. These microscopic pollen grains are normally invisible to the human eye.
Our office counts pollen on a daily basis using an electronic device termed a rotorod. The rotorod spins one of every six minutes over a 24-hour period and collects the pollen on a greased rod’s surface.
Once collected, the rods are stained and the pollen counted by Dr. Callanan or B. Shaddy, L.P.N. The results are published in the Idaho Statesman as a public service. Online pollen counts are now available on this website. The pollen data is vital to the understanding of the area allergens. Without such information, formulating an allergy extract for the allergy patient is guesswork. Each season the pollen pattern changes, as it is weather dependent. The spring tree pollen time is especially variable. The heavy rain in May suppressed the pollen count. Ideal pollen conditions consist of hot, dry, windy weather. The wind disperses high volumes of pollen, resulting in flares of allergy symptoms. These conditions occurred during the final week of May, producing high counts of grass pollen.
Southwest Idaho has a long growing season. The worst allergic pollens are grass in late May and especially the first two weeks of June to the Fourth of July. Plus, high mountain pastures of Timothy can bloom in July. The sagebrush pollen is comparable to grass as a cause of allergy, causing late summer and fall symptoms. Sagebrush pollen peaks from September 15 to October 15 in Boise. The weed season (Russian thistle, ragweed, etc.) is of moderate importance allergenically in August and early September. As in most areas of medicine or science, allergic information is not static. Even though I have been sampling pollen since 1971 in Southwest Idaho, a new location at Mercy Medical Center North revealed new spring pollens that have significant allergic potential, namely mulberry, an ornamental tree, and rumex, an introduced weed.
In closing, I should emphasize the importance of integrating a seasonal allergy patient’s symptoms with direct skin testing and a daily area pollen count. This approach, in conjunction with immunotherapy, offers the best prospect of relief for moderate to severe seasonal allergy symptoms.
*An allergist is a physician trained in the general field of internal medicine or pediatrics with a further two years of training in the specialty of allergy. Allergists are also board certified in their general field, as well as the specialty of allergy.