Letter to the editor re: Mallol J, Riquelme C, Aguirre V, Martinez M, Gallardo A, Sanchez C, et al. Value of bronchial reversibility to salbutamol, exhaled nitric oxide and responsiveness to methacholine to corroborate the diagnosis of asthma in children. Allergol Immunopathol (Madr). 2020;48(3):214–22. https://doi. org/10.1016/j.aller.2019.11.001