Food Allergies

What Is a Food Allergy?

A food allergy is one type of food hypersensitivity reaction mediated by the immune system and involves allergic antibodies against specific foods. When an allergenic food comes in contact with the allergy antibody IgE, the antibody causes the release of chemicals into the bloodstream, producing the various reactions and symptoms seen.

Symptoms may include gastrointestinal symptoms such as bloating, nausea, vomiting, diarrhea, or throat itching; cutaneous symptoms such as hives, eczema, or other skin rashes; and respiratory symptoms including asthma, nasal congestion, and nasal itch. Other symptoms such as vascular headaches and colic have also been seen in individuals with food allergies.

These allergic symptoms need to be distinguished from other adverse reactions to foods, such as food intolerance, toxic food reactions, food-borne infections, and chemicals or additives in certain foods which may mimic allergic symptoms or psychological reactions.

It is important to note that there is no well-documented evidence that foods or food allergies cause learning disorders, seizures, behavioral problems, psychiatric disorders, fatigue syndrome, or hyperactivity.

What Is Known About Food Allergies?

1. Food allergies are relatively common, particularly in infants, ranging between 2 and 5% of the general population, with the incidence being highest in infants.
2. Although potentially hundreds of foods can be allergenic, certain foods cause the greatest number of symptoms: eggs, fish, shellfish, soy, wheat, peanuts, and tree nuts.
3. The most common organ systems affected by food allergies are the skin and gastrointestinal tract.
4. Food allergies can occur even in very young infants and can be tested for.
5. Many infants and children tend to outgrow food allergies. However, the older one gets, the less the chance of outgrowing a specific food allergy.
6. Allergies can be diagnosed by skin tests and blood tests. These tests have value only in the presence of a comprehensive history.
7. Although allergy shots are very effective for inhalant allergies such as pollens and dust mites, allergy shots for food allergies have not been proven effective and may cause severe or even fatal reactions.
8. Allergy treatment plans including placement of "food extract" under the tongue are ineffective.

Diagnosis

1. A careful history is the most important part of diagnosing food allergy.
2. Symptomatic dietary elimination including food diaries are helpful.
3. Selective food challenges under medical guidance in a blinded fashion.
4. Carefully selected skin tests and blood tests. Positive skin and blood tests have relevance only in the context of a compatible history.

Treatment

1. Recognition and avoidance of offending foods.
2. Careful reading of labels and attention to commercially prepared foods.
3. Pre-treatment with antihistamine, steroids, or cromolyn is of unproven value.
4. Where there is a history of a severe or life-threatening reaction to food, injectable epinephrine in the form of an Epi-Pen or Ana-Kit should be immediately available at all times. Family members, companions, and school nurses must also be taught how to administer epinephrine as well as how to recognize the symptoms of food allergy. Particular attention should be taken when eating at restaurants and at schools, with close scrutiny of menus and dietary selections. Despite all of these measures, fatalities continue to occur, and only proper vigilance can provide true protection.

If you have further questions, please contact your primary care physician or our office: Omaha: 402-391-1800 Lincoln: 402-464-5969