What would most likely provide clues regarding to the source of a patient's allergic reaction?

Clues regarding the source of a patient's allergic reaction can often be gleaned from their medical history, including details about recent exposures to allergens such as foods, medications, or environmental triggers. The timing and severity of symptoms, as well as any previous allergic reactions, can also help identify the allergen. Additionally, skin tests or blood tests for specific IgE antibodies can provide further insights into potential allergens responsible for the reaction.