Many people believe they are allergic to certain foods, but true food allergies are not as common as you may think. In fact, only about 1.5 percent of adults and about 6 percent of children have true food allergies — an adverse reaction to a food triggered by the immune system. More people suffer food intolerance, an unpleasant reaction to a food that does not involve the immune system.

This may offer you small comfort if you’ve had a bad experience with a food and fear another incident. A real food allergy, also known as hypersensitivity, can cause serious problems and even death. Each year, approximately 200 people in the United States alone die of food-related reactions. If you develop a reaction to a particular food, tell your doctor about it. Tests can help diagnose a food allergy, so you can take steps to avoid a repeat problem.

In a true food allergy, your immune system mistakenly sees a specific food or a component of food as a harmful substance. Your immune system triggers certain cells to produce antibodies to fight the food allergen. So, the next time you ingest that food, even the smallest amount, the antibodies sense it and signal your immune system to release histamine and other chemicals into your bloodstream. These chemicals cause a range of allergic signs and symptoms that I already have mentioned.

Symptoms of a food allergy usually develop within an hour after consuming the offending item. Symptoms include hives, itching and swelling of the face, lips, tongue, throat or extremities. Wheezing, difficulty breathing, nasal congestion, abdominal pain, nausea, vomiting, diarrhea, dizziness, and light-headedness also may be present.

During a severe allergic reaction to food, called anaphylaxis, a person could suffer constrictions of the airway, making it difficult to breathe. The victim may go into shock, suffer a severe decrease in blood pressure and develop a rapid heart rate. Dizziness and loss of consciousness also may occur.

The top offenders triggering allergic reactions in adults include certain proteins in tree nuts (walnuts and pecans), peanuts, shellfish (shrimp, lobster, and crab), fish, eggs, milk, wheat and soybeans. Proteins in these eight major foods are estimated to cause 90 percent of allergic reactions.

Certain factors such as family history and age may place you at a greater risk for developing a food allergy. If other allergies such as hay fever, asthma, hives or eczema are common in your family, you are at increased risk for developing a food allergy. Food allergies are most common in children, especially toddlers and infants. As you grow older, your digestive system matures and your body is less likely to absorb food and the food components that trigger allergies. Many children typically outgrow allergies to milk, soy, wheat and eggs. Severe allergies and allergies to nuts and shellfish are more likely to endure into adulthood.

See a doctor or allergist if you experience food allergy symptoms shortly after eating. If possible, see your doctor when the allergic reaction is happening. This will aid the physician in making a diagnosis. Your doctor may perform a physical exam, ask you to describe your symptoms, have you keep a food diary, and suggest you eliminate suspected foods. Also your physician may suggest allergy skin testing to determine your reaction to particular foods and draw a blood sample to measure your immune response to offending foods.

The only way to avoid an allergic reaction is to avoid foods that cause symptoms. Seek emergency care and treatment if you develop any signs or symptoms of anaphylaxis. You may need to carry an “epi pen” — a syringe of epinephrine. Consider wearing a medical alert bracelet or necklace to alert others if you already have had a severe reaction. For less severe allergies, your doctor may prescribe antihistamines, which can be taken after exposure to an allergen to control your reaction and help relieve discomfort.

Frequent travelers are well advised to carry language translation cards. One brand, Select Wisely, makes cards that were brought to my attention as a helpful solution for travelers with food allergies or food restrictions. The cards are available in more than 20 languages. If you require cards in a language not currently in Select Wisely’s inventory, visit the company’s Web site at www.selectwisely.com to access their special order page.

For more information about food allergies, visit www.fda.gov.

Warning Signs

Some countries use potentially allergic foods in their sauces and seasonings. Read product labels carefully. Peanuts are present in some types of Dim Sum and hot mustard greens in China. Rice is sometimes mixed with barley and soybeans for flavor in Korea. Borscht can be thickened with barley in Russia. Cookies, chocolate candy and cakes often contain ground peanuts or nuts in the United States.