Asthma in children and young people with sickle cell disease: a diagnostic dilemma.

Asthma is a common complication in children and young people with sickle cell disease (CYP-SCD), contributing to increased morbidity and mortality. However, diagnosis is challenging due to overlapping SCD-related symptoms and pulmonary complications. This narrative review evaluates the utility of objective measures (spirometry, fractional exhaled nitric oxide -FeNO-, and blood eosinophil count -BEC-) in asthma diagnosis in CYP-SCD. Systematic search identified ten studies comparing asthmatic and non-asthmatic CYP-SCD and data were extracted and critically appraised. Spirometry trended towards lower values and increased obstructive patterns in asthmatic CYP-SCD. Although data interpretation was limited due to inhaled corticosteroid use, likely influencing the inability of FeNO and BEC to differentiate asthma status, alongside SCD-specific pathophysiology. Standardised diagnostic criteria, consistent use of reference ranges and further research into alternative lung function tests and asthma phenotyping are essential.