By Jeff Daniels EBS Medical Columnist
What precisely is a food allergy? The term “allergy” in general is often loosely used to explain a set of symptoms, ranging from mild itching to life-threatening anaphylaxis, that occur from a certain exposure.
A food allergy is an adverse effect resulting from a specific immune response occurring consistently upon exposure to a given food. A food allergy has substantial negative effects on health and quality of life for kids and adults with this condition.
One major problem with diagnosing food allergies is that the testing that has been traditionally used—and even newer methods of testing—can give misleading results and fail to truly diagnose significant allergies. More often than not, testing will over-diagnose food allergens. This means that tests that use multiple panels of multiple food allergens, in the hunt for one specific food, are of no good use.
A patient’s medical history is the most important tool for making the correct diagnosis. A food allergy diagnosis must be considered when allergic symptoms (rash, itching, swelling, difficulty breathing) occur within minutes to hours upon ingesting a specific food, especially if it recurs on repeat exposure.
Most, but not all, significant allergies to foods are caused by an overproduction of a certain immunoglobulin called IgE. IgE triggers the release of histamine, which can lead to hives, facial swelling, throat swelling, asthma and even anaphylactic shock. These symptoms could be life threatening, and having the right dose of epinephrine for intramuscular injection is the recommended way to treat a reaction.
There are other types of immune-mediated reactions to foods that don’t involve IgE. Some foods cause intense abdominal pain about two hours after ingestion. The term for this condition is protein-induced enterocolitis. In some people, ingestion leads to mucous-coated bloody stools, a condition called allergic colitis. Allergy tests that look for excess IgE will not help diagnose this condition.
An oral food challenge is the definitive test for determining if an infant, child or adult truly has a food allergy. Since a life-threatening reaction could occur from such exposure, this type of test has to be well thought out and performed by an allergist who specializes in treating severe reactions.
There has been a sea change in the thinking about helping children avoid developing certain food allergies. Newer thinking about allergy prevention includes the recent endorsement of introducing allergenic foods in an infant’s diet earlier than previously advised. This includes peanuts, a leading cause of severe allergies. We now know that we can specifically decrease the incidence of peanut allergy by introducing peanuts as early as four to six months. Such exposure prevents infants who are at a high risk for peanut allergy from becoming allergic to peanuts, but not other allergenic foods.
Once an allergy has developed, avoidance of the offending food is of utmost importance. Attempts to de-sensitize an individual with shots, drops and a host of other unproven methods usually have poor results.
Treatment of a reaction, mild or severe, involves the administration of epinephrine (also called adrenaline) into a muscle. The epinephrine can be delivered with an Epi-Pen or similar intramuscular injection device. There is an adult dose (0.3 cc) and a child’s dose (0.15 cc), but they’ve yet to manufacture an infant’s dose (0.075 cc). Epi-Pen devices are expensive, but could be life saving. Antihistamines and steroids also have a place in treatment.
Dr. Jeff Daniels was the recipient of the 2015 Chamber of Commerce Chet Huntley Lifetime Achievement Award had has been practicing medicine in Big Sky since 1994, when he and his family moved here from New York City. A unique program he implements has attracted more than 800 medical students and young doctors to train with the Medical Clinic of Big Sky.