Some members of the Anacardiaceae family, such as cashew nut, pistachio nut
and mango, have been reported to cause immediate allergic reactions. We re
port three cases of anaphylaxis to cashew nuts. With the aim of describing
the allergens existing in cashew and pistachio nuts, patients were prick te
sted with cashew and pistachio extracts. Specific IgE against both nuts was
studied by CAP and SDS-PAGE/immunoblotting. It was found that skin tests a
nd specific IgE to cashew and pistachio nuts were positive in the three pat
ients. Both nuts showed several protein bands in SDS-PAGE. The strongest Ig
E-binding bands had similar molecular weights (15, 30 and 60 kDa) in cashew
and pistachio nuts. These main bands were found to be sensitive to reducin
g agents. It was concluded that these three patients suffered immediate rea
ctions to cashew nut due to an IgE-mediated mechanism.