What exactly is an allergic response?

A reaction: This is your body reacting to what it determines is a foreign protein in your body. Everybody is "programmed" to react to different things or sometimes none at all. So an allergic response is a protective reaction to what your body feels is abnormal.

Allergy: It is an ige mediated hypersensitivity response to whatever is a trigger in your body that causes a release of multiple mediators, with the predominant mediator being histamine.