There might be a risk of anaphylaxis due to omalizumab therapy

Xolair (Omalizumab), a humanized mAb that binds to the CH3 domain, near the binding site for the high-affinity type-I IgE Fc receptors of human IgE, can neutralize free IgE and inhibit the IgE allergic pathway without sensitizing mast cell and basophils.We propose that mediators and cells classically involved in pro-coagulant and anticoagulant pathways altogether play a role in asthma and urticaria  pathophysiology and omalizumab effect.

I had  a female patients with severe persistent allergic asthma , aged 58. Anti Nuclear Antibody,and hepatitis markers (HBsAg, HBsAb, anti HCV HIV, thyroid antibodies were negative in patients. Autologous Serum Skin Test were positive in patients. Liver, thyroid, and renal function tests, serum IgG, IgA, IgM, levels were within normal ranges. Skin prick tests (SPTs) were highly positive for mite and mold. The specific IgE levels were correlated with the SPTs. Total IgE level were 480 IU/L. Her body temparature was 38.5 ⁰C . Patients on omalizumab therapy had laryngeal oedema during a common cold infection after omalizumab injection. Pulse steroid (500 mg prednisolon) was given. We did not stop omalizumab therapy. Oral antihistaminics and mast cell stabilizing agens used for treatment afterwards.  

We  do not suggest omalizumab during  the first five  days of  viral infections such as common cold.