Thank you for your inquiry.
You are correct that pine nuts are actually seeds. We do not know, unfortunately, the major allergen of pine nuts, but there are several studies which have isolated components which were allergenic in the particular patients evaluated.
However, there is very little information on potential crossreactivity between pine nuts and other foods, including nuts. There is one study which showed crossreactivity with peanuts (1), and another with almonds (2).
In addition, there are patients who have had anaphylactic episodes to pine nuts who have demonstrated allergy to other nuts as well (3), but there are also patients who were only mono-sensitized to the pine nut (4). Thus, unfortunately, we cannot give you a definitive answer as to which nuts or other foods might be cross-reactive in your patient except to say that crossreactivity evidently does occur and has been demonstrated to almonds and peanuts. It is not known whether patients who have shown anaphylactic sensitivity to pine nuts as well as other nuts or seeds do so because of cross-reacting antigens or the fact that they simply are reacting separately because of their highly atopic nature.
The issue, therefore, of whether pine nuts should be avoided in patients who are allergic to nuts and seeds can only be decided by clinical judgment. However, in most instances, we advise that patients who are allergic to nuts to avoid all nuts, including pine "nuts".
Thank you again for your inquiry and we hope this response is helpful to you.
1. A MA, Maselli JP, Sanz Mf ML, Fernandez-Benitez M. Allergy to pine nut. Allergol Immunopathol (Madr) 2002; 30(2):104-8.
2. de las Marinas D, Vila L, Sanz ML. Allergy to pine nuts. Allergy 1998; 53(2):220-2.
3. Rubira N, Botey J, Eseverri JL, Marin A. Allergy to pine nuts in children.
Allerg Immunol (Paris) 1998; 30(7):212-6.
4. Ibanez MD, Lombardero M, San Ireneo MM, Munoz MC. Anaphylaxis induced by pine nuts in two young girls. Pediatr Allergy Immunol 2003; 14(4):317-9.
Phil Lieberman, M.D.