What symptom indicates an allergic reaction to a transfusion?

An allergic reaction to a blood transfusion is characterized by specific symptoms, with hives and wheezing being key indicators. Hives, or urticaria, represent an immune response where the body is reacting to an allergen, which in this case could be components of the donated blood or even substances used in the transfusion process. Wheezing, on the other hand, indicates bronchospasm or narrowing of the airways, which can occur during an allergic reaction as the body's immune system responds.

This combination of symptoms is particularly significant because they reflect an immediate hypersensitivity reaction, which may range from mild to severe, and prompt recognition is critical for management.

Other symptoms like an increasing temperature typically point to a different type of reaction, such as a febrile non-hemolytic reaction, which is not necessarily an allergy. Low back pain can signal hemolytic reactions, and an increased pulse may result from various causes, including anxiety or fluid volume changes, but does not specifically indicate an allergic response.