Page 12 - Volume 11 Number 5

Dealing with
Annoying Allergies
About 25 percent of people suffer from some sort of allergy. These allergies can manifest in a variety of ways, from mild skin eruptions to nasal congestion, and even severe respiratory distress. Regardless of the symptoms they cause, or the material (allergen) that initiates the allergic reaction, all allergies have something in common – namely, they are an immune system response to a substance that typically causes no reaction in the majority of the population. Common allergens include pollens, dust mites, various foods, animal dander and molds, although almost anything can induce an allergic reaction in susceptible people. It is important to note that not all reactions to specific substances are allergic. Some substances are simply toxic and the reaction they cause is direct and not mediated by an immune system reaction.
While the actual mechanism of allergic reactions is quite complicated, let’s try to simplify it to aid in our understanding of why allergic reactions occur and what we can do to minimize their effect on us.
The first step in the allergy chain is sensitization. In this step, one is exposed to an allergen, let’s say pollen. The pollen causes specific cells of the immune system to produce antibodies specific for that pollen. These antibodies are proteins called immunoglobulins, and will react only with the specific allergen that induced them. Unlike most antibodies, the immunoglobulins involved in allergic reactions, called IgE, do not circulate in the bloodstream, but rather bind to cells called mast cells that are present in the body’s connective tissues. On a subsequent exposure to the allergen, the antibodies on the mast cells interact with the allergen and results in the release of several chemicals from the mast cell, including histamine, which causes small blood vessels to dilate and makes smooth muscles in the trachea to tighten, heparin that decreases blood clotting and serotonin which causes larger blood vessels to contract. There are other chemicals released as well, but you get the basic idea. It is these chemicals that cause the symptoms that accompany an allergic reaction such as nasal stuffiness, trouble breathing, skin rashes and, in some cases vascular collapse (anaphylaxis), which can be fatal.
Why some people’s immune systems overreact to the presence of generally innocuous allergens while other’s
10 • KING AIR MAGAZINE
do not is poorly understood. There may be a genetic component to this excessive sensitivity as allergies seem to run in families.
From a pilot’s perspective, typical allergies are a nuisance but are not serious. Nasal allergies however, can cause enough nasal congestion to result in blockage of the Eustachian tube (the tube that connects the middle ear to the nasopharynx) and this can result in
A pictorial view of the allergy chain.
by Dr. Jerrold Seckler
MAY 2017