An allergen is a general term used to describe something that causes an allergic reaction.Allergens are tiny particles found on certain substances and can be transmitted in a variety of ways.The most commonly inhaled allergens are pollen, mould, dust mites and pet dander.Pollens frequently found in Bermuda air at Easter include: Easter lilies, mulberry, nettle, periwinkle, Palmetto palms, Chinese Fan palms, plantain weed, dandelion, daisies, roses, snapdragons, sugar cane, Bermuda grass and many ornamental grasses.Additionally, garden fertilisers contain allergens that can affect allergy sufferers.