What condition might lead to increased heart rate among allergic reaction symptoms?

Increased heart rate during an allergic reaction is closely associated with histamine release. Histamine is a chemical that the body produces during allergic responses, which can lead to various physiological changes. When histamine is released, it causes blood vessels to dilate, which can lead to a drop in blood pressure. In response, the heart compensates for this adjustment by beating faster, resulting in an increased heart rate.

Nasal congestion, pruritus (itching), and hives are common symptoms of allergic reactions but do not directly influence heart rate. While they indicate that an allergic process is occurring, they do not have the same cardiovascular implications as histamine release does. Thus, histamine's direct role in altering vascular dynamics is why it is linked to tachycardia (increased heart rate) in the context of an allergic reaction.