A food allergy is an abnormal response of the body's immune system to certain foods. This is not the same as food intolerance, although some of the symptoms may be very similar.
A person must be exposed to the food at least once before the allergic symptoms occur. At that time, the immune system releases IgE antibodies that react to the food. Histamines are released, which cause allergy symptoms such as hives, asthma, itching in the mouth, trouble breathing, stomach pains, vomiting, or diarrhea.
About 90% of all food allergies are caused by 8 foods, that include:
Some facts about food allergies:
Eggs, milk, and peanuts are the most common causes of food allergies in children
Peanuts, tree nuts, fish, and shellfish commonly cause the most severe reactions.
Nearly 5% of children under the age of 5 years have food allergies.
From 1997 to 2007, food allergies increased 18% among children under age 18 years.
Most children "outgrow" their allergies, however, allergies to peanuts, tree nuts, and shellfish may be lifelong.
According to the National Institute of Allergy and Infectious Diseases, it doesn't take much food to cause a severe allergic reaction -- 1/44,000 of a peanut can cause a severe reaction in a highly allergic person.
Allergic symptoms may begin within minutes to an hour after eating the food. The following are the most common symptoms of a food allergy. However, each person may experience symptoms differently. Symptoms may include:
Swelling, itching of lips and mouth
Tightness in the throat or hoarse voice
Nausea and vomiting
Diarrhea and cramps
Hives, or itchy, raised bums
Swelling of the skin
The symptoms of a food allergy may look like other medical conditions or problems. Always consult your doctor for a diagnosis.
Anaphylaxis is a severe allergic reaction. It is life-threatening. Symptoms can include those above as well as the following:
Trouble breathing or wheezing
Flushing of the skin
Itching of palms, soles of feet
Low blood pressure
Loss of consciousness
Anaphylaxis is a medical emergency. Call 911 for immediate medical assistance. Severe allergic reactions are treated with epinephrine. Those with known severe allergies should carry emergency kits with self-injecting epinephrine or Epi-pens.
The goal of treatment is to avoid the food that causes the allergic symptoms. There is no medication to prevent food allergies, although research is ongoing.
You need to be prepared should you eat something with the food that causes your allergic reaction. You may need an emergency kit to stop severe reactions. Make sure you talk with your health care provider about what you should do.
There are medications available for some symptoms caused by food allergy after the food has been eaten. Discuss available medications with your doctor.
As in adults, it is very important to avoid these foods that cause allergies. If you are breastfeeding your child, it is important that you avoid foods to which your child is allergic.
You may need to give vitamins to your child if he or she is unable to eat certain foods. Discuss this with your child's doctor.
Your child's doctor may also prescribe an emergency kit. Be sure to ask your child's doctor about an emergency kit if you don't already have one.
Some children under the supervision of their doctor, may be given certain foods after a period of 3 to 6 months. This determines whether or not the child has outgrown the allergy.
The following related clinical trials and research studies are currently seeking participants at Massachusetts General Hospital. Search for clinical trials and studies in another area of interest.
Read about three patients who have benefited from services at the Food Allergy Center.
With the hope of making a long-term impact in the field, The Food Allergy Center at Massachusetts General Hospital (MGH) and MassGeneral Hospital for Children (MGHfC) has been established to diagnose and treat known and suspected cases of food allergies.
After-school activities can be difficult with a food allergic child. Rose Ann Miller talks about her own experience sending her food allergic child to summer camp. Learn about how she worked together with the Food Allergy Center to prepare herself, the camp and her child for this new life hurdle.
Nancy S. Rotter, PhD, a pediatric psychologist in the Food Allergy Center at Massachusetts General Hospital, treats children who are impacted by medical illness and specializes in understanding the challenges of preparing allergic children for transitions at different developmental stages. Sarah Wolfgang talks about her own experience managing her day to day activities with her two allergic children.
Qian Yuan, MD, PhD, is a gastroenterologist and clinical director at the Food Allergy Center (FAC) at Massachusetts General Hospital. Before coming to Mass General, Dr. Yuan worked with renowned immunologist and allergist K. Frank Austen, MD, at Brigham and Women’s Hospital in Boston, where he sparked an interest in Eosinophilic Esophagitis (EE or EoE). Read about the exciting research projects and advancements in EoE at the center.
Research at the Food Allergy Center including an oral immunotherapy study of peanut-allergic children, a study of older adolescents and adults with milk and peanut allergies, and plans for a new, multi-food study with Stanford University, and more.
The Food Allergy Center at Massachusetts General Hospital has conducted more than 200 food challenges with a pass rate of about 70 percent. A food challenge is the most definitive procedure for testing whether someone can tolerate a specific food. Parents from the Food Allergy Center talk about their own experiences with food challenges.
The Food Allergy Center is currently enrolling peanut allergic children ages 7–21 years in an oral immunotherapy (OIT) study, which involves administering small doses of peanut powder, increased over time. Read about Deb Edmunds’ insiders experience with her daughter, Ashley Edmunds, who is currently enrolled.
In addition to practicing pediatric allergy/immunology at MGHfC and the Newton-Wellesley Hospital outpatient Pediatric Specialty Ambulatory Care Center, Dr. Iyengar conducts translational research on breast milk factors implicated in the development of allergic disease. As an Associate Investigator of the Harvard Clinical Nutrition Research Center (HCNRC) at MGH, she studies the role of breast milk in modulating gut mucosal responses in allergic disease.
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