Allergens: It triggers allergic reactions by stimulating the immune system to produce antibodies (IgE antibodies) and releasing histamine and other chemicals that cause inflammation and allergic symptoms. These symptoms can range from mild (e.g., sneezing, itching) to severe (e.g., anaphylaxis).
Irritants: It directly damages or irritate tissues upon contact, leading to symptoms such as redness, swelling, itching, or pain. Unlike allergic reactions, irritant-induced reactions do not involve the immune system and are not mediated by antibodies.