30 Days Allergy & Hayfever Relief Cetirizine Tablets can be used to prevent and treat allergic conditions such as hayfever and allergic skin reactions. Exposure to pollen, pet fur, house dust or an insect bite can cause the body to produce histamine. The release of histamine causes allergic symptoms which can include rashes, sneezing, watery eyes and a running or blocked nose. Cetirizine is a 2nd generation antihistamine, which means it does not cause drowsiness in the majority of people. This medicine treats people suffering from hay fever (seasonal allergic rhinitis), perennial allergic rhinitis (a similar condition to hay fever caused by allergies, that continues throughout the year) and urticaria (swelling, redness and itchiness of the skin).Antihistamines like cetirizine relieve the unpleasant symptoms and discomfort associated with the above conditions, such as sneezing, itchy, runny and blocked nose, itchy, red and watering eyes and itchy skin rashes.