I think 2.10 y.o. DS is allergic to sunflower seeds as they bring his face up in a rash just as other allergens do. (He has diagnosed allergies to hazelnuts, peanuts, kiwi & coconut and suspected allergies to egg, cucumber, melon and banana.)
Presumably if he's allergic to the seeds, he'd be allergic to sunflower oil and margarine made with sunflower oil? We've been avoiding the seeds for some time but it only just occurred to me that the oil & marg we use could be a problem.