Mammals (including humans) can have an allergic reaction to insect venom
(antigen) without prior exposure. Such is rare.
However, recent prior exposure to insect venom [ie. repeated incidents
(several days or weeks apart) of bee stings from the same species of bee]
can increase levels of antigen specific immunoglobulin "IgE". Then,
re-exposure to the same species venom induces an anaphylactic reaction
(which can be fatal).
Therefore, the risk of a life-threatening anaphylactic reaction increases,
in pre-disposed individuals, with repeated incidents of exposure to the same
antigen. Ultimately the second or third sting incident in a "season" is
much higher risk. Those individuals with pre-existing asthma, autoimmune
disease, and eczema are at even higher risk.
73, Scott W3TX
TowerTalk mailing list