Background: Although peanuts and peanut butter are well recognized as food allergens, few reports describe allergic reactions associated with eating peanut flour.
Objective: To describe an allergic reaction that occurred in a peanut-sensitive woman who ate undeclared peanut flour that was part of a flavor ingredient contained in a dry soup mixture, and to estimate the amount of peanut protein the patient ingested.
Methods: The patient was interviewed, medical records from her emergency room visit were reviewed, and the manufacturer of the soup mix was investigated to ascertain the proportion of the soup mix constituted by the undeclared peanut flour.
Results: Minutes after ingesting the soup, a 33-year-old woman experienced a systemic allergic reaction. She was treated successfully in the emergency room with intravenous fluids, corticosteroids, and diphenhydramine. Investigation of the soup manufacturer revealed that undeclared peanut flour was a component of a flavoring ingredient in the soup. Based on the concentration of peanut flour in the flavoring, we estimated the patient ate approximately 45 mg of peanut protein.
Conclusions: Inadvertent ingestion of peanut flour by peanut-sensitive individuals may lead to systemic allergic reactions.