Food Allergy (Pediatric) Initial Assessment

A key part of the diagnostic work-up is a detailed allergy-focused clinical history. This allows the estimation of the likelihood (pretest probability) that a patient has an IgE-mediated food allergy and guides the choice of allergens to test for. Obtain the following information: Age at onset of symptoms; suspected food/foods that caused the adverse reaction and the symptoms that occurred (organ involved and severity of reaction); time interval between ingestion of food and development of symptoms, and the duration of symptoms; the amount of food that caused the reaction; the type of food (raw, cooked or processed) and route of exposure (ingested, inhaled or touched); reproducibility of the reaction in relationship to food ingestion; other cofactors (eg exercise, alcohol, infection, drugs [eg NSAIDs]); length of time from previous reaction; details of previous medications for the presenting symptoms, including response to these treatments; previous diagnosis of food allergy and result of elimination diet, if available; the adequacy of diet and foods avoided for personal, cultural or religious reasons; and for children, obtain their feeding history (if breastfed, consider mother’s diet), including age of weaning. It is important to identify comorbidities, risks and predisposing factors for possible recurrence (eg history of previous anaphylactic reactions, history of atopy, asthma even if well-controlled, adolescence, and the family history of atopic disease or any type of food allergy). The family history of first-degree relatives remains the most practical and useful tool in identifying allergy-prone infants. The presence of allergic diseases in one or both parents and in a sibling increases the likelihood of allergy in a child. This is more useful in the diagnosis of immediate food-induced allergies than delayed reactions. Although useful, history alone is not considered diagnostic of food allergy.