Food allergy affects approximately 5 percent of children and 4 percent of adults in the United States, according to the National Institute of Allergy and Infectious Diseases. Although 90 percent of food allergy is caused by eggs, wheat, soy, nuts, milk, fish and shellfish, allergy can develop to any food, including red meat.
An allergy to the protein in red meat develops when the immune system mistakenly identifies the protein as a potentially harmful substance. An antibody known as immunoglobulin E, or IgE, forms in response to the protein and is specific for that particular protein. When the person eats red meat again, the IgE responds to the protein and releases chemicals that result in the symptoms of an allergic reaction.
Symptoms typically develop within minutes to an hour after ingestion of red meat or of a food product that contains red meat. Hives -- an itchy rash composed of red wheals -- are a common symptom, although skin symptoms might be more mild and present as a localized rash around the mouth or face. The gastrointestinal tract might be involved, with symptoms of nausea and vomiting. Shortness of breath, coughing and a change in voice are symptoms of a more severe allergic reaction. People who notice symptoms hours after eating red meat may be allergic to a carbohydrate found in the meat rather than to the protein.
A diagnosis of allergy to the protein in red meat is often suspected on the basis of a person's clinical history or the chain of events that led up to the reaction. Allergy can be confirmed by performing a skin prick or blood test. A skin prick test involves scratching the surface of the skin with a small amount of the allergen and measuring the reaction. The blood test quantifies the level of IgE to the protein in red meat in order to determine whether the allergic antibodies are present.
Avoidance of all red meat and all food products that contain red meat is the primary treatment for this allergy. If an accidental exposure occurs, an antihistamine such as Benadryl can treat a localized reaction such as a skin rash. If a more systemic reaction occurs, injectable epinephrine can reverse the reaction. All people who are diagnosed with an allergy to the protein in red meat should carry injectable epinephrine with them. If this medication is used, the person should then go to the emergency room for further evaluation and treatment.
The term "red meat" encompasses beef, pork, mutton and all adult mammalian meats. Some people, however, are allergic to proteins in only one specific type of meat and may be able to tolerate other meats. For example, a person might be allergic to beef but tolerate pork and mutton without difficulty. Diagnostic testing can differentiate between an allergy to the protein in red meat vs. an allergy to the protein in specific meats. Additionally, blood testing can be performed to diagnose whether a red meat allergy is related to a carbohydrate in the meat rather than to the protein.