Although 25 percent of people think they're allergic to certain foods, studies show that about only 6 percent of children and 2 percent of adults have a food allergy.
A true food allergy is a reaction triggered by the immune system (the part of your body that fights infection). Far more people simply have a food intolerance, which is unpleasant symptoms triggered by food (but does not involve the immune system).
For example, milk allergy is much more common in children than in adults. However, most children outgrow the allergy by 2 or 3 years of age. Symptoms of milk allergy include hives, vomiting and breathing problems after consuming a dairy product. Many adults may experience symptoms similar to milk allergy, as adults often have trouble digesting the sugar in milk. This is called "lactose intolerance," and it isn't an allergy because it doesn't involve the immune system. The symptoms of lactose intolerance are bloating, cramping, nausea, gas and diarrhea.
The most common immediate symptoms of food allergy include the following:
The person may also feel that something bad is going to happen, have pale skin because of low blood pressure or lose consciousness. The most common chronic illnesses associated with food allergies are eczema and asthma.
Food allergy can be fatal if it is severe enough to cause a reaction called anaphylaxis (say: "anna-phil-ax-iss"). This reaction blocks the airways and makes it hard for a person to breathe. Fast treatment with a medicine called epinephrine (say: "epp-in-eff-rin") can save your life. If you or your child has a severe allergy, your doctor might give you a prescription for epinephrine self-injection pens. Your doctor can show you how and when to use the pen. If your doctor thinks you might need to use this medicine, you'll need to carry one with you at all times.
A person having an allergic reaction should be taken by ambulance to a hospital emergency room, because the amount of adrenaline being pumped into the body can be dangerous. A doctor can provide epinephrine to help slow down a person's blood circulation, breathing and metabolism.
Although people can be allergic to any kind of food, most food allergies are caused by tree nuts, peanuts, milk, eggs, soy, wheat, fish and shellfish. These eight foods account for 90% of food allergies. Most people who have food allergies are allergic to fewer than 4 foods.
Studies have found that some food additives, such as tartrazine, or yellow No. 5, and aspartame (brand name: NutraSweet), an artificial sweetener, do cause problems in some people.
No. A condition is called a food allergy when the immune system thinks a certain protein in a food is a "foreign" agent and fights against it. This doesn't happen with sugars and fats.
Once a true food allergy is diagnosed, avoid the food that caused it. If you have an allergy, you must read the labels on all the prepared foods you eat. Your doctor can help you learn how to avoid eating the wrong foods. If your child has food allergies, give the school and other caretakers instructions that list what foods to avoid and what to do if the food is accidentally eaten. There is no cure for food allergy.
Although most children usually outgrow allergies to milk, eggs, soybean products and wheat, not all do. People rarely outgrow allergies to peanuts, tree nuts, fish and shellfish.
Manifestations of Food Allergy: Evaluation and Management by SH Sicherer, M.D. (American Family Physician January 15, 1999, http://www.aafp.org/afp/990115ap/415.html)