Tezepelumab for early-onset severe allergic asthma with persistent airflow limitation and small airway dysfunction: a treatable traits approach.

We report the case of an 18-year-old woman with early-onset severe allergic asthma and no other type 2 biomarkers except the presence of IgE, complicated by persistent airflow limitation, air trapping and forced oscillation technique-defined small airway dysfunction, who achieved significant clinical improvement with first-line tezepelumab (TZP) therapy. Initial treatments, including high-dose extrafine-inhaler triple therapy with a beclomethasone-formoterol-glycopyrronium combination, failed to improve asthma control and lung function. Given the discordance between allergic phenotype and treatable traits, such as persistent airflow limitation and small airway dysfunction, TZP, a thymic stromal lymphopoietin inhibitor with broad anti-inflammatory effects, was initiated instead of omalizumab. After 6 months of treatment, the patient showed marked clinical and functional improvement: Asthma Control Test score increased from 12 to 22, forced expiratory volume in 1 second rose from 67% to 95%, residual volume normalized, and forced oscillation technique parameters improved substantially. This case illustrates how the identification of specific treatable traits can guide personalized biologic therapy, even when conventional phenotype-driven algorithms suggest otherwise. In patients with early-onset allergic asthma and atypical functional profiles, TZP may offer a superior therapeutic option by targeting upstream airway inflammation and reversing small airway dysfunction. Our findings support a precision medicine approach in severe asthma, emphasizing multidimensional assessment and biomarker-guided biologic selection.