Conditions & Treatments

Food Allergies

A food allergy is an abnormal response of the body to a certain food.

Food Allergies

What is food allergy?

A food allergy is an abnormal response of the body to a certain food. It is important to know that this is different from a food intolerance, which does not affect the immune system, although some of the same signs may be present.

What causes food allergy?

Before having a food allergy reaction, a sensitive person must be exposed to the food at least once before. It is the second time the person eats the food that the allergic symptoms happen. At that time, when IgE antibodies react with the food, histamines are released, which can cause hives, asthma, itching in the mouth, trouble breathing, stomach pains, vomiting, or diarrhea.

What is the difference between food allergy and food intolerance?

Food allergy causes an immune system response, causing symptoms that range from uncomfortable to life-threatening. Food intolerance does not affect the immune system, although some symptoms may be the same as in food allergy.

What foods most often cause food allergy?

Approximately 90 percent of all food allergies are caused by eight foods, including the following:

  • Milk

  • Eggs

  • Wheat

  • Soy

  • Tree nuts

  • Fish

  • Shellfish

  • Peanuts

Eggs, milk, and peanuts are the most common causes of food allergies in children, with wheat, soy, and tree nuts also included. Peanuts, nuts, fish, and shellfish commonly cause the most severe reactions. Nearly 5 percent of children under the age of 5 years have food allergies. From 1997 to 2007, the prevalence of reported food allergy increased 18 percent among children under age 18 years. Although most children "outgrow" their allergies, allergy to peanuts, tree nuts, and shellfish may be lifelong.

What are the symptoms of food allergy?

Allergic symptoms may begin within minutes to an hour after ingesting the food. The following are the most common symptoms of a food allergy. However, each individual may experience symptoms differently. Symptoms may include:

  • Vomiting

  • Diarrhea

  • Cramps

  • Hives

  • Swelling

  • Eczema

  • Itching or swelling of the lips, tongue, or mouth

  • Itching or tightness in the throat

  • Difficulty breathing

  • Wheezing

  • Lowered blood pressure

According to the National Institute of Allergy and Infectious Disease, it does not take much of the food to cause a severe reaction in highly allergic people. In fact, as little as 1/44,000 of a peanut kernel can cause an allergic reaction for severely allergic individuals.

The symptoms of a food allergy may resemble other medical conditions or problems. Always consult your doctor for a diagnosis.

Treatment for a food allergy in adults

Specific treatment for a food allergy will be determined by your doctor based on:

  • Your age, overall health, and medical history

  • Extent of the disease

  • Your tolerance for specific medications, procedures, or therapies

  • Expectations for the course of the disease

  • Your opinion or preference

At this time, no medication is available to prevent food allergy. The goal of treatment is to avoid the food that causes the symptoms.

People with food allergy must be prepared to treat any accidental ingestion of the foods that cause the allergic reaction. Discuss this further with your doctor.

There are medications available to treat some symptoms of food allergy after the food has been eaten. These medications may relieve rhinitis symptoms, gastrointestinal symptoms, or asthma symptoms. Discuss this further with your doctor.

Although research is ongoing, currently, there is no allergy injection approved for the treatment of food allergies. Strictly avoiding the allergy-causing food is the only way to prevent a reaction.

Treatment of food allergies in children

After being examined by a doctor and determining foods to which your child is allergic, it is very important to avoid these foods and other similar foods in that food group. If you are breastfeeding your child, it is important to avoid foods in your diet to which your child is allergic. Small amounts of the food allergen may go to your child through the breast milk and cause a reaction.

It is also important to give vitamins and minerals to your child if he or she is unable to eat certain foods. Discuss this further with your child's doctor.

For children who have a food allergy, your child's doctor may prescribe an emergency kit that contains epinephrine, which helps stop the symptoms of severe reactions. Discuss this further with your child's doctor.

Some children, under the direction of your doctor, may be given certain foods again after three to six months to determine if the child has outgrown the allergy. Many allergies may be short-term in children and the food may be tolerated after the age of 3 or 4.

What is anaphylaxis?

Anaphylaxis, also called anaphylactic shock, is a severe and sometimes life-threatening reaction to an allergen (the items that you are allergic to are called allergens). It is a medical emergency, in most cases. The reaction to the allergen can occur seconds to as long as an hour after the exposure. It is necessary to have come in contact with the allergen at a previous time for sensitization to occur.

What causes anaphylaxis?

Anaphylaxis is caused by exposure to an allergen. The type of allergen may be different for every person. Some of the most common causes include the following:

  • Medications, such as penicillin

  • Foods

  • Dyes used for medical procedures

  • Allergy injections

  • Insect stings

  • Latex

What are the symptoms of anaphylaxis?

The following are the most common symptoms of anaphylaxis. However, each individual may experience symptoms differently. Symptoms may include:

  • Tightness or swelling of the throat

  • Wheezing or difficulty breathing

  • Uneasy sensation or agitation

  • Generalized hives

  • Severe itching of the skin

  • Nausea and vomiting

  • Stomach pain

  • Heart failure

  • Irregular heartbeats

  • Lowered blood pressure

The symptoms of anaphylaxis may resemble other medical conditions or problems. Always consult your doctor for a diagnosis.

Treatment for anaphylaxis

Anaphylaxis is a medical emergency. Immediate medical attention is necessary. Your doctor will probably treat the symptoms with an injection of epinephrine, which will help stop the severe effects caused by the allergen. If you do have an anaphylactic reaction to an allergen, your doctor may instruct you on the use of an emergency kit that contains epinephrine to have near you in case of future episodes. Discuss this with your doctor.

Treatment Programs


Massachusetts General Hospital understands that a variety of factors influence patients' health care decisions. That's just one reason why we're dedicated to ensuring patients understand their diagnosis and treatment options. Because a single option might not serve all patients, we offer a wide range of coordinated treatments and related services across the hospital. Patients should consult with their primary care doctor or other qualified health care provider for medical advice and diagnosis information.

Select a treatment program for more information:



Digestive Healthcare Center

  • Weight Center
    The Massachusetts General Hospital Weight Center is a fully integrated center within the Digestive Healthcare Center that supports the spectrum of needs for people of all ages seeking help with obesity and weight loss.
Imaging

  • Pediatric Imaging
    The Pediatric Imaging Program at Massachusetts General Hospital Imaging specializes in ensuring the safety and comfort of child patients while providing the latest technology and the expertise of specialized pediatric radiologists.
MassGeneral Hospital for Children

  • Pediatric Feeding Program
    The Pediatric Feeding Program at MassGeneral Hospital for Children diagnoses and treats feeding and swallowing disorders, or dysphagia, in infants, toddlers, children and adolescents.
  • Food Allergy Center
    A multidisciplinary team at MassGeneral Hospital for Children’s Food Allergy Center provides evaluation and treatment for children with known and suspected food allergies and related conditions.
  • Pediatric Anesthesia
    The Pediatric Anesthesia team at MassGeneral Hospital for Children specializes in caring for children before, during and after surgery and other procedures.
Allergy and Immunology

  • Food Allergy Program
    The Massachusetts General Hospital Food Allergy Program integrates patient-centered research and evidence-based, multidisciplinary care for adults and children with known or suspected allergies to foods including peanuts, tree nuts, shellfish, fish, milk, eggs, wheat and soy.
  • Asthma Program
    The Massachusetts General Hospital Asthma Program diagnoses and manages asthma in adults and children, and provides ongoing care to help patients effectively control their condition and enjoy a better quality of life.

Food Allergy Center patient testimonials

Read about three patients who have benefited from services at the Food Allergy Center.

The Food Allergy Center at Massachusetts General Hospital and MassGeneral Hospital for Children

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.

Summer Camp and your Food Allergic Child

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.

Food Allergy Anxieties

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.

A dream come true: working at Mass General’s Food Allergy Center

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.

What research is currently underway at the Food Allergy 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.

Oral Food Challenges

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.

Peanut Oral Immunotherapy Study at the Food Allergy Center

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.

Breastfeeding and the Development of Allergic Disease

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.

Thirteen tips to Navigate the Holidays Joyfully and Safely

Shift the focus from holiday foods and plan memorable holiday activities for your children to enjoy this season that are safe and free from allergens.

Tips for Travel

Traveling with children who have food allergies can be challenging, but with a little preparation, you don’t need to stay home.

Food Allergy Center Research Provides Hope for Future Treatment of Food Allergies

The Food Allergy Center strives to answer why some people react to certain foods. Research provides hope for future treatment of patients with food allergies.

A Nurse Who Wears Many Hats

As both a pediatric allergy and pulmonary nurse and mother of children with food allergies, Lisa provides an insight into the emerging food allergy developments.

Tips for enjoying the holidays with food allergies

MassGeneral Hospital for Children’s Food Allergy Center experts share their surefire tips for ensuring families with food allergies experience a happy and healthy holiday season.

Living a Full and Happy Life with Food Allergies

Come join us for the third meeting in our series "Living a Full and Happy Life with Food Allergies" on April 10th. Meeting at Mass General, Yawkey, 4th Floor, RM 820 from 6:30-8:00 pm. (To find the room: Face the windows after you exit the elevators, turn left and walk to the end of the hallway. The entrance is on the left.) Children 8 and older are welcome. This meeting intends to address their concerns and give them a chance to share in an age appropriate manner. Upcoming events on May 16th and June 25th.

Frontiers in Pediatrics Gastroenterology, Hepatology & Nutrition 2013

This course is designed to meet one or more of the following Accreditation Council of Graduate Medical Education competencies: Patient care; Medical knowledge; Practice-based learning and improvement; Interpersonal and communication skills; Professionalism; Systems-based practice

Our commitment to quality and safety

Mass General ensures that our patients receive the highest quality and safest care possible. Learn about our performance, our improvement goals and how we compare to other institutions.