Anaphylaxis to insect stings.

Anaphylaxis to insect stings has occurred in 3% of adults and can be fatal even on the first reaction. Large local reactions are more frequent but rarely dangerous. The chance of a systemic reaction to a sting is 5% to 10% in large local reactors and in children with mild (cutaneous) systemic reactions, and varies between 30% and 65% in adults with previous systemic reactions, depending on the severity of previous sting reactions. Baseline serum tryptase level is increased in many patients with sting anaphylaxis. Venom immunotherapy is 75% to 98% effective in preventing sting anaphylaxis.