How do allergies work (and why do they make me feel so miserable)?

Eyes itching? Nose running? Sneezing repeatedly? You're not alone. Millions of other North Americans feel just as miserable as you do. It may not be a cold, though; you may be allergic. In fact, about one in five North Americans (more than 50 million) suffer from allergies.

If you're one of these people, the good news is that you have a strong immune system, which is pumping out antibodies to fight infection. Unfortunately, your immune system is working overtime and identifying some substances as threats when other people's systems don't. These usually harmless substances are called allergens; the most common allergens are pollen, mold, animal dander and specific foods, such as peanuts.

If you have allergies, the chances are extremely high that you are sensitive to more than one allergen. The chances are also high that you have at least one parent who also had allergies; scientists think that the tendency to be allergic is inherited (although the allergy to specific substances is not). More than 60 percent of people who have allergies have a family history of allergies, too.

The Never-Ending Season

While allergies are seasonally related, it's a misconception that there's an allergy season. We can think of allergies as indoor or outdoor, and the indoor allergy season goes on all year long. Indoors, the most common allergens are house dust mites and the dander of cats, dogs, and other pets.

Outdoor allergies are seasonal, related to the plant reproduction season; billions of pollen particles are released into the air, triggering allergic rhinitis (hay fever) in susceptible people. The most potent allergenic pollens are produced by grasses, ragweeds, birch and oak trees. As the pollen count increases, so does the number of kleenexes the typical allergy sufferer goes through. Depending on where you live, the 'bad' season may be spring, summer or autumn... or all three!

However, it's not actually the pollen that people are allergic to, but rather the allergenic proteins present within the pollens. There are proteins inside of the pollen grains which are released into the atmosphere when the pollen gets wet. It's important to realize that these allergenic plant proteins may also be present in other plants that we eat. So, if you're allergic to a plant protein inside of the ragweed pollen, and that protein is also present in plant foods such as banana, watermelon and cantaloupe, then you may experience allergy symptoms when you eat these foods. These symptoms might include itching of the roof of the mouth, swollen lips, wheezing and even a closing of the throat. If you're allergic to pollen, you may also need to avoid certain foods that can also provoke an allergic reaction.

The Allergy Reaction

The immune system is your body's defence against invading agents such as bacteria and viruses. If you're an allergic person, your body responds exactly the same way to allergens as it would to any other invading agent. When you come into contact with an allergen, your immune system produces an army of antibodies called Immunoglobulin E (IgE). These antibodies swing into action by attaching themselves to mast cells (tissue cells) and basophils (blood cells) in your respiratory and gastrointestinal tracts, which in turn release inflammatory chemicals, including histamine, which cause your allergy symptoms.

When histamine is released into your nose, you sneeze and your nose runs (allergic rhinitis, commonly called hay fever). Histamine in the lungs causes spasm of the airways or wheezing (asthma). Histamine relased into the skin causes itching (angioedema, commonly called hives). And if histamine and other allergy chemicals are released all over the body, anaphylaxis, a severe life-threatening reaction, may occur.

Common Allergies

Hay fever is often mistaken for the common cold. The symptoms are similar; both people who have a cold and hay fever victims experience spells of sneezing and runny noses. But people who have hay fever may also experience itchiness of the throat, palate, and eyes, headaches and fatigue. While we associate hay fever with pollen allergies, pollen is not the only culprit; mold spores can also cause the symptoms. And some allergic people suffer from hay fever symptoms all-year round, triggered by non-seasonal allergens such as house dust components and certain molds, a condition called perennial allergic rhinitis.

Asthma may be allergic or non-allergic in origin. If the asthma is allergic, environmental allergens trigger attacks which obstruct the flow of air to the lungs when inhaled or ingested. Breathing becomes difficult and a wheezing sound is created as you try to force air through your narrowed airways. Sometimes asthma is accompanied by a troublesome cough.

Rashes, often accompanied by severe itching, are the classic symptoms of eczema. Eczema is often seen in the children of families with a history of allergic diseases. It often starts in the child's first year, appearing on the face, and spreading later to the inside of the elbows and backs of knees, the neck, the ankles, the wrists and on the backs of the hands. In most cases, eczema disappears during the teens.

The common symptoms of food allergies are similar to those of food poisoning; vomiting, stomach pains, diarrhea or constipation. This may be why doctors and patients disagree on the frequency of food allergies; while 25 percent of people claim to have them, physicans assert that only 6 to 8 percent of children under three years old and only 1 to 2 percent of adults actually do; the rest actually suffer from intolerances or occasional food poisoning (Diane Guernsey, "Live with your allergies", June, 2000).

People with food allergies may experience cluster attacks. Eating food that they're allergic to may bring on eczema, hives, and/or an asthmatic attack, as well as the unpleasant symptoms common to food poisoning. Worse, eating the wrong thing can cause anaphylaxis, which is occasionally fatal. Interestingly, only a few foods are responsible for almost all allergic reactions; milk, eggs, peanuts and tree nuts, soy and wheat, for children, and peanuts and tree nuts, fish, and shellfish, for adults.

Severe allergic reactions to insect stings can also be very dangerous. The symptoms of an allergic reaction to a bee or wasp sting include nettlerash, hives, running nose and eyes, swelling of the throat, attacks of asthma and, in severe cases, fainting. Like true food allergic reactions, expert medical treatment, preferably at the nearest hospital, is immediately required.

How to Feel Better

Identifying your allergies is half the battle to finding effective treatment. Because allergy symptoms are often similar to diseases such as colds or food poisoning, it's easy to overlook what's actually making you feel so miserable. If you seem to be suffering from a perpetual cold, or if your symptoms are more than a mild annoyance, you should see a doctor.

Avoidance is still the first line of treatment. If you know that you're allergic to a particular food, for example, be vigilant about what you eat. Ask about the ingredients of dishes, if you haven't prepared them yourself. If you're allergic to molds, avoid the moist environments where molds thrive, such as basements, areas of heavy vegetation, and piles of leaves. Guard against indoor allergens, such as dust mites, mold, and animal dander, by removing the places they proliferate, such as carpeting, drapes, feather pillows, and down comforters. Vacuum your house every day, especially the bedroom, where most of us spend most of our time at home. If at all possible, have someone who's not allergic do the cleaning. If you're allergic to animal dander, frequent, careful vacuuming will help, although the only long-term solution may be removal of your pet. If this isn't possible, at least don't allow the pet into the bedroom.

If you're allergic to pollen, the best treatment, theoretically, is to move to a place that doesn't have the particular plant pollens you're allergic to, but this isn't very practical for most people. You can, at least, limit your contact by watching pollen counts and staying indoors with the doors and windows closed when pollen counts are high. You should always keep your bedroom windows closed to avoid having wind-driven pollen in your bedroom. And you can avoid bringing outdoor allergens into your sleeping quarters by changing your clothes and washing your hair before bed during pollen season.

Even if they avoid allergy triggers scrupulously, however, many allergic people will still need medication. Fortunately, allergy medications have come a long way since the days of the drowsy antihistamines that made it difficult to work or think and impossible to drive a car. New nonsedating antihistamines, such as Claritin and Allegra, are effective for many. If allergy symptoms are severe and persist even with medications, immunotherapy may bring relief; in this treatment, your immune system is gradually desensitivized to the allergen by a series of injections of the allergen over a period of years. Your doctor can help you determine which allergy treatment is right for you. Allergies can change over time; allergies may disappear or you may develop new ones, especially if you're exposed to allergens when the body's defenses are lowered or weakened, such as after a viral infection or during pregnancy. If you're an allergic person, aging will decrease your allergies. People suffer most from allergies in their teens through their thirties. As your immune system ages, its ability to react strongly to allergens weakens, and allergy symptoms decrease. So as we sniffle and weep and pop yet another antihistamine, we can comfort ourselves with the knowledge that we will experience real relief from our allergies sooner or later. No wonder they call them "the golden years"!

Sources

Fairfield, N.J. (1988). Allergies: Nothing to sneeze at [online]. Available: http://www.uiuc.edu/departments/mckinley/health-info/dis-cond/allergy/allergies.html (June 13, 2000).

Guernsey, Diane. (June, 2000). Live with your allergies. Reader's Digest.

National Institute of Allergy and Infectious Diseases. (May 1999). Allergies: an introduction [online]. Available: http://healthlink.mcw.edu/article/926102279.html (June 13, 2000).

National Pollen Network. (2000). All about allergy [online]. Available: http://www.allernet.com/allabout/default.asp (June 13, 2000).