Better Health Through Knowledge

What causes an allergic reaction?

A typical allergic reaction happens in the following way:

  1. Allergens enter the body by being inhaled as with pollens, dust and animal dander, swallowed as with food or medicine, or injected as with penicillin or bee stings.
     
  2. If you are allergic, your body may overreact, causing excess production of IgE.
     
  3. Upon further exposure, the allergen binds with the IgE antibody and causes certain cells in your body to release histamine-like substances. These substances cause the allergic symptoms you’re familiar with, such as: itchiness, watery eyes, sneezing, congestion, runny nose and rashes.
     
How allergies are diagnosed

Accurate diagnosis of your allergy is key to successful treatment. In order to determine the specific allergens responsible, your physician will take the following steps:

History:
Reviewing history can establish how and when the symptoms appear, whether they are seasonal or year-round, and whether they can be associated with any particular activity, place or exposure.

Physical exam:
Your physical examination will focus on the eyes, ears, nose, sinuses, throat, lungs, skin and gastrointestinal tract. Results of the exam will be more informative if performed “in season,” or while the symptoms are at their peak.

Testing:
Until the discovery of IgE, the skin test was the major diagnostic tool for allergies. With this method, approximately 50 to 200 tiny scratches, pricks, or needle sticks are made – usually on the upper back or arm – with small amounts of suspected allergens. After an appropriate time period (10-30 minutes), the skin is observed for any reaction.

New, improved In Vitro tests – Hytec288 & ImmunoCAP
Soon after IgE was discovered, researchers began to work on a new type of test, an In Vitro (blood) test. The RAST was the first generation test, but is no longer available. Currently the Hytec288 and the ImmunoCAP test, both FDA approved, are used to help doctors identify the cause of your allergy. A small part of your blood sample is mixed with different allergens and observed for a chemical reaction. The laboratory’s equipment and computers analyze the reaction and measure the amount of IgE for each allergen. Results are grouped into classes from zero (negative) to six (high positive). Your doctor will discuss the importance of these results with you.

Treatment

Some allergies do disappear or moderate with time or treatment, but most patients require continuing treatment in order to maintain a symptom-free life. Your doctor can prescribe a treatment program for you that will relieve or eliminate much of your discomfort.

You may also discover you can solve your problem simply by avoiding those things that trigger your allergy. If, for example, you are allergic to eggs,  you avoid eating eggs.

Many allergens, such as pollen and dust, are unavoidable and require specific treatment. Many symptoms can be controlled by drugs such as antihistamines or cortisone.

Your doctor might also prescribe immunotherapy – allergy shots. In this procedure, small doses of the offending allergen are injected into the body over a period of time, gradually building up the body’s tolerance to that allergen.

A new alternative to shots is allergy drops, also known as sublingual immunotherapy.  They are safe and effective and offer the convenience of taking them at home.

Whatever treatment your doctor prescribes, it’s important to continue your treatment on a regular basis. Trust your doctor and stay with the program.

Allergy symptoms are responsible for more visits to the doctor’s office than any other single disease in this country. Over 40 million Americans (about 1 in 5) suffer from one or more of the allergic diseases. Allergies are considered a leading cause of school and work absenteeism, too. Fortunately, your doctor has a wide range of innovative testing and treatment techniques to make dealing with allergies a lot easier than before.

Early allergy discoveries

Allergy as a recognizable illness is nearly as old as the history of modern man. However, it was not until 1966 that the exact mechanism for the disease was discovered. Researchers found that some people produce a “skin sensitizing antibody” called IgE (for Immunoglobulin E).

Allergic patients inherit the tendency to produce an overabundance of IgE when exposed to allergens such as dust, ragweed and grass pollens.