Food Allergy & Food Intolerance


Food allergies can be frustrating, unpleasant and even life threatening. Millions of Americans suffer from food allergies, and it’s likely you’ve been affected by them at some point.

Your body’s immune system is designed to identify and attack germs that can make you sick. When your immune system mistakenly overreacts to a harmless food protein (allergen), it becomes a food allergy.

Experts believe there is a genetic link with food allergies. If someone in your family suffers from hay fever, asthma or eczema, you are more likely to have a food allergy.

Food Allergy vs. Food Intolerance

Food allergies and food intolerances are not the same thing. A food allergy involves your immune system, but food intolerance means your body can’t digest or absorb certain foods like milk, dairy or gluten. Food intolerance generally causes gastrointestinal issues like cramping, bloating and diarrhea. An allergy can result in widespread inflammation with symptoms including cramps, vomiting, diarrhea, hives, swelling, dizziness and even respiratory distress.

It’s important to confirm a food allergy through an evaluation with your doctor.

Common Food Allergens

The most common food allergens in the U.S. include:

  • Milk
  • Eggs
  • Peanuts
  • Tree nuts (Brazil nuts, cashews, chestnuts, macadamia nuts, pecans, pistachios, pine nuts, shea nuts and walnuts)
  • Soy
  • Wheat
  • Fish
  • Shellfish (shrimp, lobster and crab cause the most allergic reactions)

Symptoms of an Allergic Reaction to Food

Signs of food allergies usually occur within minutes to two hours after eating the food to which you’re allergic. Your reaction to a food allergen can range from mild to severe, affecting your skin, gastrointestinal tract, respiratory tract and, in the most serious cases, your cardiovascular system.

Mild to moderate reactions may include:

  • Tingling, itching or swelling of your mouth/lips
  • Stuffy nose, runny nose, sneezing
  • Cramping, upset stomach, vomiting, diarrhea
  • Itchiness/hives

The most severe allergic reaction to food is called anaphylaxis, and it can be deadly. If you experience any of these symptoms (or see someone having them), call 911 immediately:

  • Swelling of your throat or tongue
  • Sudden wheezing or trouble breathing
  • Feeling like you’re going to faint or pass out
  • Feeling sick to your stomach/vomiting (if occurring along with other severe symptoms)

Managing Food Allergies

The best way to manage a food allergy is to not eat the food(s) you’re allergic to. Sometimes, that’s easier said than done. Living with a food allergy requires diligence in reading food labels and asking questions when you’re eating out at a restaurant.

If you have had severe reactions in the past, your doctor may prescribe epinephrine. Epinephrine is a shot that can slow down or stop an allergic reaction. You must keep it with you everywhere you go, and if you have to use it, you’ll still need to go to the emergency room for observation because symptoms can reappear.

Call a Mercy allergist or ear, nose and throat (ENT) specialist* to discuss your concerns around food allergies. He or she may recommend skin tests and blood tests to determine which foods you are allergic to. If allergy testing is inconclusive, you may also do an oral food challenge, where your doctor observes while you eat a food to see if it causes an allergic reaction. If an allergy is confirmed, you’ll need to avoid that particular food item. If no allergies are identified, it’s likely you have a food intolerance rather than an allergy. In that case, an elimination diet where you avoid eating certain foods may be appropriate to see if your symptoms disappear.

Your mercy doctor can help you get back to enjoying your food, worry-free.

*Not all ENTs treat food allergy and food intolerance. Talk to your ENT to find out if he or she offers food allergy testing.

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