Are You Allergic or Just Sensitive?

• Oct. 03, 2012
• Topic: Wellness

Sheila L. loves discussing all things having to do with her 6-year-old daughter, but get onto the topic of the youngster’s newly emerging fruit allergies and her mom seems at a loss. She describes the peanut-free lunch tables – now a hallmark of grade school cafeterias – and her daughter’s recent allergic reactions to citrus fruits, baffled at this seemingly growing problem. “What’s the deal here? Where’s it all coming from? We didn’t have any of these problems when I was a kid.”

We throw around terms such as “allergy,” “sensitivity,” and “intolerance” much more these days, but what are we really talking about? “An allergy is the response of the body's immune system to a normally harmless substance, such as pollen, house dust mites or food,” explains Virtua allergist Jin P. Guo, MD, PhD. “Those normally harmless substances pose no problem in most people. However, these allergens are identified as threats by the immune system of an allergic individual and produce an inappropriate response.”

That response can include a runny nose, itchy eyes and mouth, skin rash, and gastrointestinal symptoms such as abdominal discomfort and vomiting. Severe allergies can cause breathing problems or a drop in blood pressure. Severe allergic reactions are also known as anaphylaxis, and can be life-threatening.

Unfortunately, explains Dr. Guo, the word allergy is commonly used to describe any unpleasant reaction to a drug, food, insect sting, or chemical, and that can be misleading. An intolerance is different from an allergy, and happens for a variety of reasons, for example, because your body does not produce sufficient quantities of a particular enzyme or chemical that is needed to break down a certain food and aid digestion. However, intolerances don’t involve the body’s immune system and, therefore, don’t usually result in life-threatening allergic reactions. So, for example, the difference between a true dairy allergy and a lactose intolerance carries an important distinction.

Just because you didn’t have allergies as a child, doesn’t mean that you’ll go through life without them. Dr. Guo notes that allergies can come and go. “Most food allergies start in childhood, but they can develop at any time in a person's life,” she says. “It isn't clear why, but some adults develop an allergy to a food they could once eat with no problem. Sometimes, a child outgrows a food allergy only to have it reappear in adulthood.”

If you want to pinpoint what you suspect may be an allergy, the most useful first step is to take an allergy history says Dr. Guo. “A good allergy clinician can usually identify the likely allergens from the history alone, and allergy tests may not be needed. However, there are occasions when tests can be useful to confirm the diagnosis.” Such tests include an allergy challenge test, skin testing, blood tests, and skin patch testing, where you body is exposed to small doses of a potential allergen to monitor your body’s reaction. Your doctor will help you determine what type of test you need to identify allergies, as well as explain the potential side effects of these tests.

“The first step in the management of allergic disease is identifying the cause of the problem,” says Dr. Guo. “In some cases, this may be obvious. However, in other cases it may require detailed investigation and necessary tests. Keeping a record of your symptoms may help medical professionals work out the allergen.”