Allergens and irritants

Allergens are the substances triggering allergies, those that make your body produce allergy anti-bodies (lgE) and react allergic. Irritants are substances that can stimulate and irritate and for example, start an allergic reaction.
Examples of allergens are tree pollen, grass pollen, mugwort pollen, animal allergens, dust mites, mould (fungi), bees and wasps, medical drugs etc., etc.