Food Allergic Patient Management

Current management of food-allergic patients consists of the dietary avoidance of causal foods and optimizing the prompt treatment of symptoms resulting from accidental exposure. An individualized approach, taking into consideration the immunologic mechanism involved, the age of the patient, the suspected degree of sensitivity, the number of implicated foods, and the severity of previous reactions, is required.

Dietary avoidance of implicated foods is accomplished through the design of a palatable, nutritionally adequate elimination diet, education regarding label reading, and a review of potential sources of accidental exposure. The ease of designing a single food elimination diet depends upon the pervasiveness of the offending food in the diet.

Diets eliminating commonly encountered foods or multiple foods are best developed with the aid of a skilled dietician experienced in working with patients with food allergies. Reliable resources for obtaining further information, such as the Food Allergy and Anaphylaxis Network, should be provided.

Wearing a medical information bracelet or necklace or carrying a card listing the patient’s allergies and other important medical information can save time, particularly when the patient is found unconscious or cannot communicate as a result of a reaction.

A food allergy action plan should be developed that lists the steps to take in case of a reaction, including the order and doses of all medications to be administered, as well as contact information for family members and health care providers. This plan should be thoroughly reviewed with patients, their family members, and all other caretakers.

Fatal allergic reactions to foods have been associated with the delayed administration of epinephrine. As a result, an epinephrine autoinjector, along with instruction about when and how to use it, should be provided to those patients considered to be at risk for food-induced anaphylaxis.

Features of the history that should prompt providing an epinephrine autoinjector include: a previous severe reaction or one involving the respiratory or cardiovascular system; generalized urticaria or angioedema during previous reactions; coexistent asthma; allergy to peanuts, nuts, fish, or shellfish; or a history of other family members with severe allergic reactions to foods.

Injection of the epinephrine dose intramuscularly into the lateral thigh is recommended, based upon studies demonstrating improved absorption by this route over subcutaneous administration.

Currently, epinephrine autoinjectors are available in doses of 0.15 mg and 0.30 mg, with the 0.15-mg dose suggested by the manufacturer for patients weighing 15 kg to 30 kg, and 0.30-mg dose recommended for those over 30 kg, with the caveat that physician discretion regarding dosing is suggested based upon the history.

Autoinjector use is preferred over the use of an epinephrine ampule and syringe, to avoid delay in administering the dose and reduce the potential for significant errors in dosing. Providing more than one autoinjector is generally recommended, particularly in situations where access to medical care is limited or could be delayed.

Once an epinephrine autoinjector is used, emergency medical services should be notified for transport of the patient to the appropriate medical facility. Other medications commonly available to patients, for use in the immediate treatment of allergic reactions to foods, include oral antihistamines and inhaled bronchodilators.

Antihistamines carried for the first-aid treatment of allergic reactions should be chewable or liquid preparations, to reduce the time required for absorption. Appropriate doses of these medications and when to use them should be reviewed.

The first-aid treatment of food-induced anaphylaxis, including the rationale for epinephrine administration, has been reviewed by Simons. Although epinephrine is the drug of choice for the treatment of anaphylactic reactions to foods, it does not reverse the symptoms of nonIgE-mediated reactions, such as food proteininduced enterocolitis, where the mainstay of therapy is fluid replacement.

Upon arrival at a medical facility for treatment of an allergic reaction to a food, the patient should be rapidly assessed and supportive care provided as indicated. Oxygen should be rapidly provided for any evidence of respiratory distress. If 10 to 15 minutes have elapsed since the initial dose, and the reaction persists or is progressing, another dose of epinephrine should be given.

Patients presenting with hypotension should receive intravenous fluids with consideration for instituting vasopressor therapy. If antihistamines have not been given or symptoms persist, an additional dose of antihistamine should be administered and use of an H2 blocker considered.

Other supportive care, such as bronchodilator therapy for patients with bronchospasm, should be provided as indicated. Looking for factors that inhibit response to therapy, such as beta-blocker use, is encouraged in patients unresponsive to standard treatment.

Intravenous glucagon may effectively treat hypotension in patients on beta blocker therapy who are not responding to the vasopressor effects of epinephrine. Before the patient with food-induced anaphylaxis is released from medical care, the means for obtaining an epinephrine autoinjector should be provided, along with appropriate teaching and arrangement for follow-up with an allergist.

Long term management of the food allergic patient involves monitoring for evidence of the development of tolerance, or for the acquisition of new food allergies, by obtaining interim histories regarding reactions to foods, and evaluating the results of immunoassays for food-specific IgE or skin testing as indicated.

Other important aspects of long-term follow-up include analyzing the diet for nutritional adequacy, reviewing the first-aid treatment of allergic reactions to foods, discussing patient concerns, and providing psychologic support. The psychologic impact on patients and their families is a frequently ignored aspect of food allergy, often successfully managed with appropriate psychosocial intervention, resulting in a significant improvement in quality of life.