Allergic eosinophilic esophagitis Any, but especially infants, children, adolescents Children: chronic/intermittent symptoms of gastroesophageal reflux, emesis, dysphagia, abdominal pain, irritability Adults: abdominal pain, dysphagia, food impaction History, positive PST, and/ or food-IgE in 50%, but poor correlation with clinical symptoms Patch testing may be of value Elimination diet and OFC Endoscopy, biopsy provides conclusive diagnosis and response to treatment information Variable, not well established, improvement with elimination diet within 6–8 wk Elemental diet may be required Often responds to swallowed topical steroids
Biopsy diagnostic: villus Lifelong atrophy Screening with serum IgA antitissue transglutaminase and antigliadin Resolution of symptoms with gluten elimination and relapse on oral challenge
From Adkinson NF Jr, Bochner BS, Busse WW, et al: Middleton’s Allergy: Principles and Practice, ed 7, Philadelphia, 2008, Mosby. OFC, Oral food challenge; PST, prick skin test.
Adapted from Sampson HA: Food allergy, J Allergy Clin Immunol 111:S544, 2003.
An in vitro serum specific IgE assay can be used to helpconfirm clinical allergy as well. Many allergists and laboratories regard the ImmunoCAP system as the method of choice.This method uses a quantitative fluorescent immunoassay,which is more sensitive than other assays; this method also has improved specificity and reproducibility compared toother assays. These tests provide supplementary informationto skin tests. Researchers have tried to determine concentrations of food-specific IgE at which clinical reactions are highlylikely to occur (Table 84-2). Patients with allergen specific IgElevels greater than 95% of the predictive value may be considered allergic, and there is no need for an oral food challenge.Monitoring the allergen specific IgE level may be helpful in predicting whether a child has outgrown the food allergy.Oral food challenges remain the standard of diagnosis andcan be performed to determine whether a child can eat thefood safely.
Management of food allergies consists of educating the patient to avoid ingestion of the responsible allergen and to initiate therapy if ingestion occurs. For mild symptoms limited to the skin only, such as mild itching or hives in the area of allergen contact, oral antihistamines such as diphenhydramine or cetirizine can be administered. If symptoms extend beyond skin, including but not limited to difficulty breathing or swallowing, tongue or throat swelling, vomiting, and fainting or symptoms not responding to diphenhydramine within 20 minutes, injectable epinephrine should be administered and immediate medical attention pursued. Types of injectable epinephrine include EpiPen (0.3 mg), EpiPen Jr. (0.15 mg), and Twinject (0.3 or 0.15 mg).
Anaphylaxis is the most serious complication of allergic food reactions and can result in death (see Chapter 81).
Hypersensitivity to egg, milk, wheat, and soy resolves within the first 5 years of life in approximately 80% of children. Sensitivity to certain foods, such as peanuts, tree nuts, fish, and shellfish, tends to be lifelong. However 20% of children who manifested peanut allergy younger than 2 years of age may outgrow it.
Avoidance of the suspect food is crucial. Careful reading of food labels is a priority. A MedicAlert bracelet with appropriate information should be worn. The Food Allergy Research & Education organization ( www.foodallergy.org ) is a useful educational resource for families and physicians.