Is going unconscious normal if having an allergic reaction?

Severe allergy: There are many kinds of allergic reactions. Some start slowly, and may produce a rash, or itching or swelling, like poison ivy, and some come very quickly and can be very serious and even cause death. Allergy to bee stings, peanuts or drugs, like penicillin can cause unconsciousness, and even death. Discuss this with your doctor, and get an Epipen (epinephrine) to keep on hand, and avoid what caused the allergy.