'allergen-rich' originates from the combination of 'allergen' and 'rich', where 'allergen' refers to a substance that causes an allergic reaction, and 'rich' means having a lot of something.

The term 'allergen' comes from the Greek word 'allergia', meaning 'other work', and 'rich' from Old English 'riche', meaning 'powerful or wealthy'.

Initially, 'allergen' referred to any substance causing an allergic reaction, and 'rich' meant abundant. Together, they describe something abundant in allergens.