Table of Contents
INTRODUCTION TO THE DISEASE
An allergen is a harmless substance that causes an allergic reaction. Allergic rhinitis, commonly known as hay fever, is an allergic response to specific allergens such as grass, dust and mould. Pollen is the most common allergen.
Body releases histamine whenever it encounters an allergen. Histamine is a natural chemical that defends our body from the allergen. This chemical causes allergic rhinitis.