Choosing to not eat peanuts or shellfish is a matter of personal taste for some people, but for those with food allergies, it’s a much more serious decision. Reactions to food allergies can range from hives and itching to difficulty breathing and anaphylaxis, a potentially life-threatening condition.
In this video, San Diego Health host Susan Taylor talks with Hannah Wangberg, MD, an allergist and immunologist at Scripps Clinic Carmel Valley and Scripps Clinic Rancho Bernardo, about food allergies and intolerances.
Food allergies are the immune system’s reaction to proteins in certain foods. It’s the job of the immune system to protect the body against infections, but sometimes it mistakenly identifies a particular food protein as a threat. When this happens, a patient may have an allergic reaction to that food. The most common food allergies are peanuts, tree nuts, egg, cow’s milk, soy, wheat, fish, shellfish and sesame.
About 32 million adults and children have food allergies in the U.S. Anyone can develop a food allergy, but people who have a family history of food allergies or atopic diseases, such as asthma, eczema, hay fever or seasonal allergies, have a higher risk.
Food allergy symptoms usually occur within minutes to hours of eating a food. An itchy, red rash called hives may appear anywhere on the body, and the face or lips may swell. More severe reactions include anaphylaxis, in which the immune system releases chemicals that cause difficulty breathing, a sudden drop in blood pressure, nausea or vomiting, and a fast, weak pulse. Anaphylaxis can lead to shock and may be fatal if not treated immediately with an injection of epinephrine. Many people with severe food allergies carry an epinephrine pen with them in case of exposure.
“Food allergies can be life-threatening, so if a patient eats a food and has early onset symptoms such as hives, difficulty breathing, vomiting, they should be seen in the ER right away,” says Dr. Wangberg. “After that evaluation, they really should come to allergy clinic, where we can explore the reaction in greater detail.”
Often, patients who have gastrointestinal symptoms, such as diarrhea or nausea, may blame a food allergy. However, these symptoms are more common with food sensitivity or food intolerance, which is a different condition.
“Food intolerance symptoms are typically gastrointestinal, so there may be nausea, bloating, gas, indigestion,” says Dr. Wangberg. “These symptoms can be very uncomfortable for patients, but they’re not generally life-threatening, and those reactions might be more delayed.”
Many medical conditions are associated with food intolerance. Patients who have irritable bowel syndrome, which can cause abdominal discomfort, bloating, diarrhea or constipation, often improve by eliminating foods that trigger symptoms. Those with lactose intolerance may develop bloating, cramping and gas from the lactose in dairy products. Celiac disease triggers reactions to gluten, which is found in wheat, barley and other grains.
While there are numerous home-testing kits for food sensitivity and allergy on the market, Dr. Wangberg advises against them. These tests are not backed by strong science or evaluated by the FDA, so the results may be misleading and cause confusion about which foods are truly problematic.
If you suspect you’re reacting to a particular food, whether it’s an allergy or a food intolerance, Dr. Wangberg recommends seeing your doctor to get a medical history and determine the next steps.
“If we suspect a food allergy, often times we’ll recommend skin prick testing or blood testing. Other times, we may recommend something called an oral food challenge that involves a patient coming into the allergy clinic and eating the food slowly while we observe carefully for any signs or symptoms of an allergic reaction” she says. “And, we’ll give patients the tools to identify and treat an allergic reaction should there be accidental exposures to the food.”
In cases of food intolerance, tracking symptoms with a food diary can help connect the dots. Eliminating foods that cause problems may lead to improvement within days to weeks.
“A food allergy or food intolerance can really impair your quality of life and it could potentially be dangerous,” says Dr. Wangberg. “It’s very important that you talk to your doctor about your symptoms and the appropriate treatment.”