Anaphylaxis (an-a-fi-LAK-sis) is a serious allergic response that often involves swelling, hives, lowered blood pressure and in severe cases, shock. If anaphylactic shock isn't treated immediately, it can be fatal.
A major difference between anaphylaxis and other allergic reactions is that anaphylaxis typically involves more than one system of the body.
Symptoms usually start within 5 to 30 minutes of coming into contact with an allergen to which an individual is allergic. In some cases, however, it may take more than an hour to notice anaphylactic symptoms.
Warning signs may include:
Red rash (usually itchy and may have welts/hives)
Swollen throat or swollen areas of the body
Wheezing
Passing out
Chest tightness
Trouble breathing...