Known allergens which can cause anaphylactic shock:
- Insect stings - Bee,Wasp,Ants,Ticks
- Food - Peanuts, Seeds, Fish, Shellfish, Eggs
- Plants - Spruce, Grass pollen
- Medication - Pain Killers, Antibiotics (especially Penicillin), Iodine (injected)
Anaphylaxis can also be caused by cold or exercise, usually when combined with an allergy.
Also personal experience, and info from BlueDragon and Stavr0