Asthma: Phenotyping EXacerbations

Inclusion criteria

INCLUSION * Clinician diagnosed asthma. * Male or female aged ≥ 18 and ≤ 85 years of age. * One asthma exacerbation requiring additional treatment in the year prior to informed consent. This is defined as either: 3 or more consecutive day's treatment with oral corticosteroids; for participants not on maintenance steroids, OR at least a doubling of treatment with oral corticosteroids for 3 or more consecutive days, from a stable dose, for participants on maintenance therapy with oral corticosteroids. These can be patient-reported. * On British Thoracic Society (BTS) step 1-5 treatment * Current smokers can be included, provided there is good evidence of underlying asthma (for example, a life-long history of asthma, \> 12% FEV1 reversibility or sputum or blood eosinophilia). * Able (in the Investigator's opinion) and willing to comply, with all clinical investigation requirements. * Non-English speaking participants should be proficient in their understanding of the English language, in order to be able to fully participate in the study. EXCLUSION: * Exacerbation in the 4 weeks prior to the Baseline visit. The use of biologic therapy, including Omalizumab, Mepolizumab or Benralizumab, at any time during the 3 months. * prior to informed consent. Participants who commence biologic therapy during the course of the study will be withdrawn. * A history more in keeping with smoking-related Chronic Obstructive Pulmonary Disease (COPD) * Other clinically significant respiratory diseases. * Use of regular high dose maintenance systemic corticosteroids (for example, a dose of \> 10mgs of Prednisolone daily) * Any other clinically significant medical disease or uncontrolled concomitant disease, that is likely, in the opinion of the investigator, to impact on the ability to participate in the study or the study results. * Pregnant women, lactating women or women who are planning to become pregnant. * Participants with uncontrolled hypertension. Participation in a study involving an investigational medicinal product at any time during the 3 months prior to informed consent.