The study is structured into two distinct and separate phases, an observational and an interventional.
\- Phase 1: Observational Phase The observational component of the study aims to describe the variations in airway inflammation at the onset of asthma symptoms when patients (n=50) are under the appropriate anti-asthma therapy (Standard Of Care, SOC), which includes a rapid-onset bronchodilator (RABD) as needed. The RABD used may be either salbutamol or formoterol, depending on the therapeutic strategy employed by the patient and the GINA Track followed.
Before and after taking the SOC rescue medication, the patient will measure markers of airway inflammation and clinical impact (FeNO, FEV1, PEF, VAS scale) using the "PEFESP kit" provided to each enrolled patient. They will record these values in the "patient diary" for the subsequent 48 hours.
\- Phase 2: Interventional Phase In a crossover design according to the AB/BA scheme, it will be assessed whether there are differences in the airway inflammation profile in patients (n=30) using a reliever medication containing ICS compared to a reliever medication containing only a bronchodilator.
The interventional phase consists of two open-label monitoring phases, each lasting a maximum of 3 weeks, separated by a washout period of 3 to 7 days and for a maximum of 3 symptom episodes. As in the observational part, patients will be asked to record the markers of airway inflammation and the clinical impact of symptoms at the onset of the change from stable condition and in the 48 hours following the administration of the reliever medication.
Patient with mild asthma will be the first group of severity enrolled in the study.
