Food allergies affect approximately 11 million children and adults in the United States causing symptoms such as rash, breathing difficulty and certain gastrointestinal symptoms.  Food allergy reactions are immunologically based and commonly can be detected via skin or blood allergy testing.  They are distinct from food intolerance, some examples of which are heartburn from alcohol and spicy foods, insomnia from caffeine or diarrhea and upset stomach from dairy products (lactose intolerance). 

Immediate-type reactions

Most food allergy reactions happen within one hour after ingestion.  Although many foods can be a cause, the most common ones are milk, egg, soy, wheat, peanut, tree nuts and seafood.  The most common type of reaction involves the skin in the form of itching, hives and swelling.  If swelling occurs in the throat, however, it can be life-threatening.  Involvement within the gastrointestinal tract can cause vomiting and abdominal pain.  Diarrhea may follow as long as a couple of hours later.  The most serious reaction is anaphylaxis, when multiple symptoms occur together.  In severe anaphylaxis the person may experience a drop in blood pressure which may lead to unconsciousness, a heart arrhythmia or death.  Generally immediate reactions respond to prompt injection of epinephrine (adrenaline).  Epinephrine is used for any potentially life-threatening reaction.

Oral allergy syndrome is a situation in which a person experiences limited symptoms, such as itchy mouth and throat after ingesting certain raw fruits and vegetables, but tolerates cooked or processed versions.  This phenomenon is related to cross-reacting pollen allergies.

Delayed-type reactions

Delayed-type reactions involve a different immunological mechanism, and include eosinophilic gastrointestinal disorders such as eosinophilic esophagitis (EE), and allergic eczema (atopic dermatitis) in childhood.  In these situations, symptoms may occur 1-2 days later, or are chronic.  Symptoms of EE, a relatively newly identified condition, may include hard-to-treat gastrointestinal reflux in young children, and food getting stuck during swallowing in older children and adults.  With regards to eczema, 30% of children with this chronic itchy rash will have underlying food allergies as a contributing cause. 

Treatment and follow-up
Proper management of food allergies involves identification of the triggering foods using skin or blood testing and avoidance of those foods.  Currently there are no “cures” for food allergies, although sometimes they can be outgrown, particularly in childhood.  Researchers may be able to offer means of treatment in the future, but in the meantime it is important to be aware of what you or your child is eating, read ingredient labels, and have an action plan and emergency medication available in case an accidental ingestion occurs.  We will help you identify those foods you need to avoid, develop an appropriate emergency action plan for you, and keep you informed of the latest developments.  We can also help determine if you or your child may have outgrown a particular food allergy.