Type I hypersensitivity reaction that is either severe in nature or having two or more organ systems  involved.
Clinically<unk>  and its treatment is virtually identical whether it is the traditional IgE dependent<unk>  reaction (vast majority), or the IgE independent anaphylactoid reaction
Precipitants
Food (most common)
Medications
Insect stings
Latex
Aerobic exercise
Idiopathic (rare)
Food (most common)
Medications
Insect stings
Latex
Aerobic exercise
Idiopathic (rare)
Anaphylaxis
Allergic reaction/urticaria
Heat tetany
Laryngospasm
Angioedema
Cold urticaria
Anxiety attack
Flash pulmonary edema