While an estimated 40 to 50 million Americans have allergies, only one to two percent of all adults are allergic to foods or food additives. Eight percent of children under age six have adverse reactions to ingested foods but of that 8%, only 2-5% have confirmed food allergies. With Spring/Summer Vacation planning and picnics, dining right around the corner Allergy, Asthma & Sinus Center (http://www.allergyasc.com) has provided a quick question and answer overview of Food Allergies
What are the symptoms of a food allergy?
Allergic reactions to foods typically begin within minutes to a few hours after eating the offending food. The frequency and severity of symptoms vary widely from one person to another. Mildly allergic persons may suffer only a runny nose or sneezing, while highly allergic persons may experience severe and life-threatening reactions.
The most common symptoms of food allergy involve the skin and intestines. Skin reactions include rashes (hives and eczema), while intestinal symptoms typically include vomiting, nausea, stomach cramps, indigestion and/or diarrhea. Other symptoms can be swelling of the tongue, lips or throat; asthma, with coughing or wheezing; rhinitis, often including itchy, stuffy, runny nose and sneezing; loss of blood pressure; and rarely, anaphylaxis, a severe allergic reaction that may be life threatening.
Because these symptoms can be caused by a number of different diseases other than food allergy, your physician may want to evaluate you to rule out the source of your problem.
What causes my symptoms?
A food allergy is the result of your body’s immune system over-reacting to food proteins called allergens. Normally your immune system protects the body against allergic reactions; however, in the individual with food allergy, the immune system produces increased amounts of the allergic antibody called immunoglobulin E, or IgE. When these antibodies combine with food allergens, histamine and other chemicals are released as part of the body’s immune reaction. These chemicals can cause blood vessels to dilate, muscles to contract and affected skin areas to become red, itchy and swollen. These IgE antibodies can be found in different body tissues—skin, intestines and lungs—where specific allergy symptoms such as hives, vomiting, diarrhea and wheezing occur.
Not all adverse reactions to foods are due to allergy. Some reactions to cows’ milk, for example, are related to a deficiency of an enzyme (lactase) that normally breaks down a sugar in milk (lactose). When individuals with lactase deficiency drink cows’ milk or eat other dairy products, they may experience intestinal symptoms, the most common examples include stomach cramping, gas and diarrhea. This is sometimes misinterpreted as a food allergy.
Why do I have a food allergy?
Although food allergy occurs most often in infants and children, it can appear at any age and can be caused by foods that had been previously eaten without any problems. Excessive exposure to a particular food may affect the overall rate of allergy to that food as well.
Which foods are most likely to cause a food allergy?
Nine basic foods are responsible for 95% of food allergies. They include:
• Tree Nuts
But almost any food has the potential to trigger an allergy.
Keep in mind that if you are allergic to a particular food you might be allergic to related foods. For example, a person allergic to walnuts may also be allergic to pecans and persons allergic to shrimp may not tolerate crab and lobster. However, complete restriction of all “related” foods based on an allergy is rarely necessary.
Note: Oral allergy syndrome or OAS is a type of food allergy noted by allergic reactions in the mouth. The most common reaction is an itching or burning sensation in the lips, mouth, ear canal, and/or pharynx. Sometimes other reactions can be triggered in the eyes, nose, and skin. Swelling of the lips, tongue and uvula and a sensation of tightness in the throat may be observed. Notify your doctor if you notice any of these symptoms.
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Allergy, Asthma & Sinus Center, http://www.allergyasc.com, has offices located conveniently in Greater Knoxville, Athens, Cookeville, Crossville, Johnson City, Maryville, Morristown, Mt. Juliet, Oak Ridge, Old Hickory, Sevierville, TN and Corbin, KY