Glossary Terms ALLERGEN October 4, 2022 Posted by Sean McWard 09 Jul Allergen [al-ler-jen] What it is: A substance that causes an allergic reaction in the body. This reaction can be topical or systemic. VIDEOS RELATED TO THIS TERM Dafne FernandezRussian Almond: ApplicationScarlett Senter LEARN MORE TERMS View All Glossary Terms CHEMICAL REACTION ORGANIC KERATIN CELLS