Each year, an estimated 30,000 Americans visit hospital emergency rooms after suffering a severe food allergy, the FDA reports. While allergies often occur in childhood, they can develop in later years and after eating certain foods. These foods can cause dangerous symptoms, including swelling, also known as edema. As the number of people with food allergies grows, understanding your risk factors and how you can protect yourself may help avoid a life-threatening allergic reaction.
Common Food Allergens
While the National Institute of Allergy and Infectious Diseases links more than 170 foods to food allergies, six are commonly known to cause the condition in children in the U.S. These foods include eggs, peanuts, milk, tree nuts such as walnuts and pecans, soy and wheat. In adults, tree nuts, peanuts, shellfish such as lobster, crab and shrimp, and fish are the most frequent triggers of food allergies. Together, the foods are responsible for more than 90 percent of all food allergies, according to Kurt Kurowski and colleagues in the June 2008 issue of "American Family Physician." Children who develop milk, egg, wheat and soy allergies often outgrow the allergies by age 5, while those who develop allergies as adults tend to have them for life.
Edema
A food allergy occurs when your immune system attacks a food protein it views as harmful to your body and produces immunoglobulin E, or IgE, antibodies. The antibodies trigger your immune system to release chemicals, including histamine, that cause your blood vessels to swell. During an allergic reaction, your throat, tongue, lips, face or other body parts may swell. In severe allergic reactions, you may experience swelling of your eyelids, throat or airways, a condition known as angioedema.
Risk Factors
Your risk of developing a food allergy increases if you have a family history of the condition. If both parents have allergies, you have a 75 percent chance of also having allergies, the American College of Allergy, Asthma and Immunology reports. That number falls to 30 to 40 percent if only one parent has an allergy. If you previously had a food allergy or have other diseases, such as eczema or asthma, your chance of a food allergy also increases. You are at greater risk of developing angioedema if you previously had hives or suffered an anaphylactic reaction, a serious whole body allergic reaction.
Treatment
For a minor allergic reaction, your doctor may suggest an over-the-counter antihistamine to reduce swelling. In severe cases and during an anaphylactic reaction, you may require epinephrine, a type of self-injectable medication that relaxes airway muscles and tightens blood vessels. The medication, which includes brand names EpiPen, Epipen Jr. or Twinject, is available by prescription only. Once you receive the drug, visit your nearest hospital immediately for treatment.
Prevention
Avoid foods that may cause an allergic reaction. Read food labels carefully to note the presence of any common food allergens. By law, U.S. food manufacturers must list the eight common food allergens --- egg, tree nuts, milk, peanut, soy, wheat, shellfish and fish --- that are in or may be in their products. If you are pregnant or nursing, experts recommend breastfeeding your baby for the first four months to prevent food allergies. Also, avoid introducing solid food to your baby until 4 to 6 months. Wear a medical-alert bracelet or necklace to advise medical professionals of your allergies, and carry an injectable epinephrine device with you at all times.
References
- FDA; Food Allergies --- Reducing the Risks; January 2009
- National Institute of Allergy and Infectious Diseases; Guidelines for the Diagnosis and Management of Food Allergy in the United States; Joshua A. Boyce, et al.; December 2010
- "American Family Physician"; Food Allergies --- Detection and Management; Kurt Kurowski, et al.; June 2008
- American College Allergy, Asthma and Immunology: Food Allergies
- MayoClinic.com; Food Allergy; February 2011
- Medline Plus: Food Allergy
