Unfortunately, allergies can sometimes prove fatal. Some people can be so sensitive to some allergens that they go into anaphylactic shock. This is a severe, whole-body reaction that can result in nausea, hives, abdominal cramps, and possibly constriction of the airways. Many people prone to these dangerous attacks carry an epinephrine autoinjector, which is a medical device that can quickly administer epinephrine, or adrenaline. If someone goes into anaphylactic shock and does not have medication on hand, experts say you should call 911 and to begin rescue breathing and CPR if necessary.