It is also used to relieve itching and hives. It works by blocking a certain natural substance (histamine) that your body makes during an allergic reaction.Levocetirizine does not prevent hives or prevent/treat a serious allergic reaction (such as anaphylaxis).

Levocetirizine does not prevent hives or prevent/treat a serious allergic reaction (such as anaphylaxis). If your doctor has prescribed epinephrine to treat allergic reactions, always carry your epinephrine injector with you. Do not use levocetirizine in place of your epinephrine.