What is anaphylaxis – a commonly asked question on the subject of food allergies. Anaphylaxis occurs when certain allergens whether they are foods, bee venom, or other such substances cause the body to produce huge amounts of histamine because the body recognizes the substance as an invader. It is an extreme overactive response of the immune system to deal with an invading substance. The histamine causes hives and difficulty in breathing due to inflammation which may progress to the point of airway blockage causing respiratory and cardiac arrest. It can be life-threatening and these severe reactions are treated initially with epinephrine. Those with severe allergies usually carry an EpiPen which is an injectable dose of epinephrine.