It seems more and more children are being diagnosed with food allergies or food sensitivities. To help us understand the symptoms of these conditions and what a parent should know we called on Manish Ramesh, M.D., Ph.D., head of Montefiore’s Food Allergy Center with locations in the Bronx and Scarsdale to answer a few critical questions.
1. What are the principal symptoms of food allergies and food sensitivities?
The most common type of food allergy also called “IgE mediated allergy,” “severe anaphylactic type of allergy” or simply “food allergy,” is caused by an abnormal “IgE” type antibody against foods. This antibody, designed to protect against certain kinds of infections, instead starts reacting against the food that we eat.
The symptoms of an allergic reaction can start within minutes of eating the food. They include:
• Hives (red, itchy, slightly swollen patches of skin
that may look like bug bites)
• Swelling usually around lips, mouth or tongue
or eyes
• Runny nose
• Vomiting
• Itchy or swollen throat
• Cough
• Wheezing
• Difficulty breathing
• Loss of consciousness
Any reaction in which there is breathing difficulty, loss of consciousness, or two or more of the symptoms listed above occurring together, is considered a severe reaction also called “anaphylaxis.”
At different times the same food can cause different reactions in the same person and symptoms can differ from person to person. A variety of factors such as the amount of food, how the food was prepared, whether other food or drink was consumed with it, whether the person is asthmatic and the general state of health can determine the severity of a reaction. Because of this it is not possible to predict how severe any given reaction will be. It is important to keep in mind that any food-allergic person can develop a severe reaction. It is for this reason that all food-allergic persons must carry an epinephrine autoinjector.
Food sensitivities or food intolerances are not caused by these antibodies and are not life threatening. Some food intolerances such as lactose intolerance are caused by the absence of an enzyme, which helps digest the sugars in milk. Food intolerances usually cause gastro-intestinal symptoms such as indigestion, flatulence, abdominal pain or diarrhea. Drinking “Lactaid” instead of regular milk helps prevent these symptoms.
Celiac disease is a special kind of food sensitivity. It is caused when the immune system reacts to a wheat protein called “gluten” and starts attacking the intestine. The principal symptoms are abdominal pain, diarrhea, gas and bloating, and loss of appetite. In severe cases, nutritional problems, anemia, weak bones and loss of weight can develop. Of late, people have noticed that some people have difficulty digesting gluten and can develop stomach pain, nausea, bloating but do not have celiac disease. This condition is not well understood and is being studied. People with these symptoms do not develop life-threatening allergic reactions (such as those seen in wheat allergy) or intestinal damage (as seen in celiac disease).
2. What are the principal signs of allergic reaction?
During an allergic reaction, a person may notice hives, wheezing, swelling of lips, mouth, eyes or tongue, difficulty breathing or loss of consciousness.
3. What are the most common allergic reactions (food allergies) and food sensitivities?
The most common foods that people are allergic to include:
• Milk
• Eggs
• Peanut
• Tree nuts (e.g. cashews, walnuts, almonds,
pecans, pistachios)
• Wheat
• Soy
• Fish (e.g. cod, salmon, tilapia)
• Shellfish (e.g. shrimp, crab, lobster)
The most common food intolerance or sensitivity is lactose intolerance.
4. How are food allergies diagnosed?
Food allergy can usually be diagnosed without much difficulty when it is accompanied by its typical symptoms and by performing certain tests such as blood and skin tests. Blood tests look for the “IgE” type of antibodies in your blood. Skin tests involve making a scratch on your skin with an extract of the food that you may be allergic to and looking for a hive-like response at the test site. Sometimes, the results of such tests can be inconclusive. When this happens, allergists may perform a feeding test called a “food challenge.” In a food challenge, the allergic person eats the suspected food while being observed closely by the doctor or a nurse.
5. When should a parent take their child to be tested for food allergies?
If your child develops hives or swelling, itchy mouth, cough, wheezing, vomiting or diarrhea within minutes to hours of eating a food or you observe your child’s eczema getting worse after introduction of a food in your child’s diet, then you should take your child to his pediatrician or an allergist to test for allergies.
Manish Ramesh, M.D., Ph.D., is head of Montefiore Medical Center’s Food Allergy Center with locations in the Bronx and Scarsdale, N.Y.
