Useful components of the medical history
| Was one of the most common allergenic foods ingested within 2 hours before the onset of the reaction? | A few foods (cow’s milk, eggs, peanuts, tree nuts, shellfish, finned fish, wheat and soy) account for most food allergies14 |
| Had the suspect food been ingested previously? | A history of repeated tolerance to the food means it is less likely the culprit |
| Had there been prior reactions? | Repeated reactions to the same food means it is more likely the culprit |
| What is the age of onset? | Onset in childhood is mostly likely due to milk, egg, wheat or peanut allergy, whereas onset in adulthood is usually due to nut or shellfish allergy or to pollen–food allergy syndrome8 |
| What was the mode of preparation? | Larger amounts of food are more likely to cause a reaction, although reactions to trace amounts can also occur; a person reactive to whole cow’s milk or egg may tolerate lesser amounts of heated forms in baked goods (e.g., cookie, muffin)15,16 |
| Were there augmenting factors? | Exercise, infection, use of medications (e.g., nonsteroidal anti-inflammatory drugs), menstruation and alcohol consumption can increase the likelihood of reactivity or make a reaction more severe17 |
| What symptoms were experienced by the patient? | Cutaneous, respiratory, gastrointestinal and cardiovascular symptoms are indicative of an IgE-mediated reaction. An older individual may experience a sense of “doom,” whereas a young child may cry, stop playing or become listless |