Itchy eyes, a congested nose, sneezing, wheezing and hives: these are symptoms of an allergic reaction to the environment caused when plants release pollen into the air, usually in the spring or fall. A colloquial term for seasonal allergies — and the inflammation of the nose and airways (and all that comes with it) — is hay fever, but that's a misnomer — those suffering from hay fever almost never get a fever, and hay is not the culprit. Doctors and researchers prefer the term "allergic rhinitis."
Tree pollen, grass and other environmental evils
About 40 million Americans suffer from seasonal allergies. The most common culprit is pollen — that dastardly (but necessary) powder released by trees, grasses and weeds to fertilize the seeds of neighboring plants. As plants rely on the wind to do the work for them, the pollination season sees billions of microscopic particles hit the highways of the air, and many of them end up taking a wrong turn up our noses and into our mouths.
Spring bloomers include ash, birch, cedar, elm and maple trees, plus many species of grass. Weeds pollinate in the late summer and fall, with ragweed being the most volatile. The pollen that sits on brightly colored flowers, it is interesting to note, is rarely responsible for hay fever, because it is heavier and falls to the ground rather than being borne in the air. Also, bees and other insects carry that pollen directly from one flower to the next without ever crossing paths with vulnerable human noses.
Mold allergies are also a bit different — mold is a spore that grows on rotting bits of log, dead leaves and grasses. While dry-weather mold species exist, many types of mold thrive in moist, rainy conditions, releasing its “seeds” overnight. Both in the spring or fall allergy seasons, pollen is released mainly in the morning hours and travels best on dry, warm and breezy days.
How do scientists know how much pollen is in the air? It’s more than just a guess. Specialists charged with counting pollen set a trap where ambient air flows freely. The trap — usually a glass plate or rod coated with adhesive — is analyzed every few hours, and the number of particles collected is then averaged to reflect the particles that would pass through the area in any 24-hour period. That measurement is converted to pollen per cubic meter. Mold counts work much the same way.
A pollen count is an imprecise measurement, scientists admit, and an arduous one — at the analysis stage, pollen grains are literally counted one by one under a microscope. It is also highly time consuming to discern between types of pollen, so they are usually bundled into one variable. Given the imprecise nature of the measurement, total daily pollen counts are often listed simply as low, moderate or high.
The pollen grade still gives sufferers a good idea about whether to stay indoors or not, or how much allergy medication to pack for the day. That’s because hay fever symptoms, at their peak, can be debilitating for some sufferers and, at best, a serious nuisance for others. Classic hay fever symptoms include nasal congestion and runny nose, watery eyes, and postnasal drip. More severe reactions include hives and airway constriction.
All of these symptoms are an immune overreaction by your body attempting to protect the vital and sensitive respiratory system from outside invaders. The antibodies produced by the body succeed in keeping the foreign invaders out, but also cause the symptoms characteristic of allergic responses.
Hay fever treatments
Short of staying indoors through hay fever season, allergy sufferers may choose to combat symptoms with medication designed to shut down or trick the immune sensitivity in the body. Whether over-the-counter or prescription, most allergy pills work by sending chemicals that bind naturally to histamine — the pesky protein that reacts to the allergen and causes an immune response — coursing through your body, negating the protein’s effect.
Other allergy remedies attack the symptoms at the source. Nasal sprays contain active ingredients that decongest by soothing irritated blood vessels in the nose, while eye drops both moisturize and reduce inflammation. Doctors may also prescribe allergy shots for those particularly afflicted.