Thing That Causes a Reaction, Like Pollen, Gluten
This page is the CodyCross answer for the clue below from House of Horrors, Group 1115, Puzzle 1 (No Electricity).
Question is: Thing That Causes a Reaction, Like Pollen, Gluten
and the answer is: ALLERGEN
Word Meaning:
ALLERGEN — (medicine) A substance which causes an allergic reaction.
Definitions from Wiktionary.