Omalizumab injection is used to decrease the number of asthma attacks (sudden episodes of wheezing, shortness of breath, and trouble breathing) in people with allergic asthma (asthma caused by inhaling substances such as dander, pollen, and dust mites) whose symptoms are not controlled with inhaled steroids. Omalizumab is also used to treat chronic hives without a known cause that cannot successfully be treated with antihistamine medications such as diphenhydramine (Benadryl), cetirizine (Zyrtec), hydroxyzine (Vistaril), and loratadine (Claritin). Omalizumab is not used to treat other forms of hives or allergic conditions. Omalizumab injection is in a class of medications called monoclonal antibodies.