(2) even if allergens are different, if there are similar parts (molecules), cross-reactions can cause allergy or anaphylaxis.
(3) If a substance similar to the internal chemicals involved in the onset of allergy enters the body, it can cause a reaction similar to allergy.
(4) Haptens are substances that do not directly produce antibodies but bind to proteins and become antigen-like, reacting with existing antibodies. https://en.wikipedia.org/wiki/Hapten
Anyway, even researchers have a lot of unknowns, so I think it's better not to put unnecessary things into the blood unless they are related to immediate life.
According to research, allergens are:
(1) foreign (amino acids, peptides, proteins, bacteria, fungi, pollen, drugs, etc.)
(2) even if allergens are different, if there are similar parts (molecules), cross-reactions can cause allergy or anaphylaxis.
(3) If a substance similar to the internal chemicals involved in the onset of allergy enters the body, it can cause a reaction similar to allergy.
(4) Haptens are substances that do not directly produce antibodies but bind to proteins and become antigen-like, reacting with existing antibodies. https://en.wikipedia.org/wiki/Hapten
Anyway, even researchers have a lot of unknowns, so I think it's better not to put unnecessary things into the blood unless they are related to immediate life.