Although any food can have the potential of causing an allergic reaction, there are a limited number of foods that contribute to the majority of these reactions. These foods include: milk, soy, wheat, egg, peanut, tree nut, fish, and shellfish. Most known food allergens are proteins, however, carbohydrates can also lead to allergic reactions. Within the last 15 years, galactose-alpha-1,3-galactose, also referred to as alpha-gal has been identified as a carbohydrate allergen. A bite from the Lone Star tick can cause people to become sensitized to alpha-gal and develop an allergy to meat, at any time. Once sensitized to alpha-gal, allergic symptoms can develop after eating most mammalian meat, such as beef, lamb, pork, or goat.
Symptoms can include itching, hives, rash, swelling, nausea, vomiting, diarrhea, runny nose, difficulty breathing, or anaphylaxis. Anaphylaxis is a severe, life threatening, allergic reaction. Most reactions to food occur immediately. However, an allergy to alpha-gal can take a few hours (3-5 hours after eating red meat) to occur.
Your trusted Allergy Partners Allergist will take a thorough history including a series of questions including:
- What food was eaten?
- How much of the food was eaten?
- When and what symptoms occurred?
- How long did symptoms last?
- How was it treated?
A skin test to specific foods can be performed in the office and provide results in about 20 minutes. Blood tests measure the amount of Immunoglobulin E (IgE) antibody to the specific food to be tested, as well as the alpha-gal allergen. These results will help make a diagnosis.
The best treatment for a food allergy is strict avoidance of the trigger(s). It is important to read ingredient labels on food products and to know any other names the allergen can be labeled. Symptoms from a food allergy can range from mild to severe/life-threatening. Previous reactions do not predict the severity of future reactions and therefore can be unpredictable. The first line treatment for anaphylaxis is epinephrine. Once a diagnosis has been confirmed, your Allergy Partners Allergist prescribes an epinephrine auto-injector and will review how and when to use it.
Chitra R Natalie, MD
Allergy Partners of Bloomington