Treating a Severe, Rapidly Developing Allergic Reaction to an Allergy Injection For a rapidly developing allergic reaction causing hives (red. Itchy blotchy rash), swelling of hands, feet or face, breathing difficulties like wheezing, chest tightness, shortness of breath, then do the following: Administer an Epi-Pen Injector if on hand to give. Remove the blue cap and press […]