Cann't see it myself, could be an old wifes tail.
It is to do with inhaled dust from bees triggering your immune system. There are a few research papers out there. For example:
Journal of the Royal Society of Medicine Volume 78 March 1985. Allergy to insect stings: a review, Pamela W Ewan MB MRCP
A few patients, usually beekeepers, become sensitized by the inhalant route to allergens derived from the insect bodies. These are distinct from the allergens in venom. These patients have inhaled 'bee-dust' while working amongst bees.
Curr Opin Allergy Clin Immunol 5:343–347, Bee venom allergy in beekeepers and their family members, Ulrich R. Muller
It has been suggested [8] that during their work
in the beehive, atopic beekeepers get more easily sensi-
tized than non-atopic beekeepers, most likely through
inhalation of bee dust or multiple stings.
Clinical Allergy, 1975, Volume 5, pages 389-395, Clinical and immunological studies of beekeepers
IgE antibodies to both bee venom and whole bee body protein were found in some beekeepers. There was a poor correlation between the levels of these antibodies, suggesting that in general they are reacting with different antigenic determinants. In contrast to the findings with bee venom IgE antibodies, the level of whole bee body IgE was similar in beekeepers with and without reactions. This finding supports the importance of bee venom antigens in the etiology of systemic allergic reactions.
As beekeepers are exposed to inhalation of bee 'dust' as well as frequent stings, this finding of antibody production to bee body proteins is not unexpected.
The original source of the suggestion may be reference [8] above which is
Comparison of the Atopic Background between Allergic and Non-Allergic Beekeepers, S. Miyachi, M.H. Lessof, D.M. Kemeny, L.A. Green Current Opinion in Allergy and Clinical Immunology 2005, 5:343–347
but I do not have free access to that article and am unwilling to pay $38.
Paul