Background: T2 low asthma in children is an emerging yet underexplored endotype that challenges traditional views of type 2 inflammation. Recent data suggest that it is more prevalent than previously thought and is defined by low type 2 biomarkers, non-allergic clinical profiles, and strong associations with modifiable comorbidities such as obesity, passive smoke exposure, and recurrent respiratory infections. This phenotype often shows a poor response to standard inhaled corticosteroid therapy and T2-targeted biologics, underscoring the urgent need for improved diagnostic and therapeutic approaches. Methods: This narrative review conducted a literature search from PubMed and WoS databases (2020–2025), focusing on T2-low asthma defined by low blood eosinophils (<150–300/µL), FeNO (<20–25 ppb), and absent atopy in children under 18. Results: This review highlights the heterogeneity of T2-low asthma, including subtypes from neutrophilic/Th 17-high to paucigranulocytic airway remodeling and metabolic driven forms, as well as diagnostic challenges from biomarker supresssion by high-dose therapies. Pragmatic phenotyping algorithms using routine tests enable identification, directing comorbidity management over ineffective biologics. Conclusions: Systematic T2-low phenotyping in pediatric practice, alongside prospective studies and non-T2 therapy trials, promises precision medicine to enhance outcomes for these children, moving beyond eosinophil-centric care.
Type -2 (T2) low asthma in children represents a clinically important yet still insufficiently recognized endotype. Current data suggest that it is more prevalent than previously thought and is defined by low type 2 biomarkers, non-allergic clinical profiles, and a high burden of comorbidities such as obesity and passive smoke exposure, while remaining largely understudied phenotype in terms of validated biomarkers and specific targeted therapies. This review aims to highlight and clarify T2-low asthma in children by summarizing emerging evidence on risk factors, pathophysiological mechanisms, bi-omarkers, and treatment strategies, with the goal of informing and improving future care for affected children.