Prior research indicates that IgE-mediated phatophysiological mechanisms often occur in allergic diseases, including severe allergic asthma (SAA). With the hypothesis that the anti-IgE monoclonal antibody omalizumab might benefit patients with SAA and multiple allergic comorbidities (AC)—including perennial/seasonal rhinitis, conjunctivitis, atopic dermatitis (AD), and food allergy—researchers conducted a post-hoc analysis of participants in the STELLAIR study. At 4-6 months after starting omalizumab, patients with at least three AC showed a higher combined response to treatment (74.7% vs 58.3%) and experienced reduced yearly exacerbation and hospitalization rates (88.9% vs 77.4% and -94.0% vs -70.5%, respectively) when compared with those with less than three AC. Those with more than three AC were also more likely to experience improvements in AC at 12 months (85.3% vs 51.9%). While all participants experienced improvements in AD (73.2%) and food allergies (38.7%) at 12 months, presence of AD was associated with greater omalizumab effectiveness at months 4-6 and greater AC improvement at month 12. Results were similar regardless of patient age.