All patients will be provided diphenhydramine (25 mg po TID) as rescue medication for pruritus relief on an as-needed basis (to a maximum of three doses in 24 hours). Patients who require treatments other than diphenhydramine (e.g., prednisone) to treat persistent/worsening disease will be discontinued from the study. Patients will also be provided an epipen and trained in its use as per American Academy of Allergy, Asthma & Immunology (AAAAI) guidelines for omalizumab.