Omalizumab and food allergy: does reaction severity improve in adult patients?

Introduction
In adults, IgE-mediated food allergy is associated with clinically relevant allergic reactions of variable severity. Omalizumab has been shown to reduce food-related reactions in selected populations; however, evidence in adults, particularly those with chronic spontaneous urticaria (CSU), remains limited. Aim: To evaluate whether omalizumab treatment reduces the severity of food-related allergic reactions upon re-exposure in adult patients with chronic spontaneous urticaria and concomitant IgE-mediated food allergy.

Material and methods
Adult patients with CSU receiving omalizumab and a documented history of IgE-mediated food allergy were retrospectively evaluated with a limited prospective component. Reaction severity before and after omalizumab treatment was assessed using the EAACI, Brown, and Ring–Messmer classification systems. Analyses were restricted to patients who were re-exposed to the culprit food after treatment. Baseline clinical and laboratory parameters were compared between responders and non-responders.

Results
Forty adult patients were included (median age: 42 years; 70% were female). Anaphylaxis history was more frequent in patients with chronic spontaneous urticaria and concomitant IgE-mediated food allergy than in CSU patients without food allergy (p = 0.040). Thirty-one patients were re-exposed to the culprit food after initiation of omalizumab treatment. Reaction severity was significantly reduced following treatment across the EAACI, Brown, and Ring–Messmer classification systems (all p < 0.001). Baseline total IgE levels, eosinophil counts, serum tryptase levels, and atopy status were not associated with clinical response. Higher baseline C-reactive protein levels were observed among responders (p = 0.039).

Conclusions
Omalizumab treatment was associated with a consistent reduction in the severity of food-related allergic reactions upon re-exposure in adults with CSU and IgE-mediated food allergy. Clinical improvement occurred largely independently of conventional allergic biomarkers.