Anaphylaxis
Venom from stinging or biting insects, like bees and wasps (Hymenoptera) or kissing bugs (Triatominae), may cause anaphylaxis.  If a person has a bad allergic reaction to venom once, they have a greater risk of having anaphylaxis if they are stung or bitten again.  However, half of the people who die of anaphylaxis have had no anaphylactic reaction before.