What Is an Allergy?

An allergy is the body's hypersensitivity to substances in the environment. Allergic reactions range from mild itching, sneezing or eczema (inflamed, itchy skin), to severe hives, hay fever, wheezing, and shortness of breath. An extreme allergic reaction can result in anaphylactic shock, a life-threatening situation in which a person's airway swells shut and blood pressure drops.

Scientists believe allergies originated millions of years ago as a way for the human body to rid itself of parasites and invading worms. The body fights these and other invaders by producing an antibody called immunoglobulin E or IgE for short, in the intestines and lungs. Without modern parasites to fight, IgE reacts to other foreign substances in the body. IgE triggers immune cells to release a number of chemicals, one of which is histamine. Histamine produces hives, watery eyes, sneezing, and itching. The more a person is exposed to allergens, the more the body produces IgE; hence, allergies often get worse with age.

The Nose Knows

The most common symptom of seasonal allergies is allergic rhinitis, otherwise known as hay fever. Symptoms of allergic rhinitis closely mimic those of the common cold.

But there are differences. A cold runs its course in 7 to 10 days. Allergic rhinitis can drag on for weeks or months. Despite its nickname, "hay fever" does not cause fever. With a cold, nasal discharge may be thick and yellow. In allergies, it is generally thin and clear. An allergy is often accompanied by eye, skin or mouth itchiness and can often be traced to a specific trigger.

The first step in handling chronic allergies is a visit to an allergist. The doctor will begin by taking a detailed medical history. From that, he or she can establish a list of suspected allergens. To confirm the diagnosis or figure out puzzling allergy symptoms, the doctor may order an allergy skin test.

With this test the practitioner makes a series of punctures, each containing a small amount of one suspect allergen in solution, in a grid pattern across the surface of the patient's back. If the patient is allergic to any of the allergens, a raised red spot like a hive, called a "wheal and flare," will appear after about 20 minutes, at that site.

Depending on the patient's history, a person may be tested for as few as six allergens or as many as 80. Beware of physicians who suggest testing for 200 to 300 allergens because at that quantity, the skin may react to everything and the test will be useless.

A more sensitive test is the intra dermal test which works by injecting a drop of extract into the skin. "The intra dermal test is advisable if the puncture test is negative, to avoid a serious overdose reaction.

Treating the Symptoms

Once the causes and severity of the patient's allergies are determined, the doctor can prescribe a treatment plan. The first, most obvious, step is to avoid the allergen.

The next step in treating allergies is medication. Antihistamines, which interfere with the effect of histamine, are often prescribed. A major side effect of antihistamines is drowsiness, and some types produce more than others. The term "non sedating" antihistamine is widely used to describe some prescription drugs, but it is not 100 percent accurate and is not a term used by FDA.

All the antihistamines produce drowsiness in patients, but some do more so than others." Benadryl (diphenhydramine hydrochloride), for example, is a common brand name oral antihistamine available without a prescription. It is well known to cause drowsiness in about half of people who take it. For those people, it's best taken at night. Two prescription antihistamines that have less sedation are Allegra (fexofenadine) and Claritin (loratidine).

Among nose sprays, there is Astelin (axzelastine hydrochloride), an antihistamine. Other nasal sprays contain steroids to combat congestion. These include Beconase and Vancenase (both contain beclomethasone dipropionate), Flonase (fluticasone propionate), Nasalide (flunisolide), and Nasacort (triamcinolone acetonide). The drawback to these medications is that they may take a week or so to be maximally effective and can sting and even damage the nasal septum (the soft bony division in the middle of the nose) if the spray is directed at it. Tell your doctor if you have any bloody discharge while using these sprays.

Less stinging but still helpful is the nasal spray Nasalcrom (cromolyn sodium). This nasal spray helps turn off the allergic process in the nose before it starts. It must be taken more often than a nasal steroid. Doctors often recommend this for children because it is extremely safe and it is available without a prescription.

Don't be tempted to treat an allergy with an over-the-counter decongestant nasal spray for more than three days. After a few days of use you may get a "rebound" effect, and your nose may become even more congested than before. These drugs are more useful for short-term use to relieve nasal congestion associated with a cold.

Allergy Shots

What should you do if you've tried every drug in the pharmacy and still sneeze from January to December? Allergy shots, also known as immunotherapy, can offer long-lasting relief for many people.

Getting allergy shots is a long process. Over the span of three to five years, the allergy patient receives a small injection of the offending allergens usually twice a week at first, then less often with larger doses as time goes by. These small doses desensitize the body's immune system to each allergen. After at least six months to a year, the sneezing, itching and hives may begin to subside. After about five years, it's possible for many to stop the shots completely.

About a third of patients who get allergy shots are cured after treatment, another third have a partial relapse, and the rest will relapse completely. Those not cured may be helped by resuming the shots.

Another approach to allergy shots is called "rush immunotherapy. Patients spend several days receiving repeated shots to desensitize them against allergens. They then go on the maintenance schedule earlier. Studies have suggested rush immunotherapy can be at least somewhat effective under certain circumstances, but more study is needed to show widespread safety and effectiveness. Currently, no allergen extracts are approved by FDA for this approach.

In the Nose, Not the Head

Allergies can certainly be life-threatening, but for most people they are merely annoying. For many, occasional sneezing, itching and watery eyes is no big deal. Others grow accustomed to the inconvenience and accept it as part of spring or fall, even if their symptoms are more severe.

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