Asthma and Respiratory Co-Morbidities.

Asthma is a common respiratory condition with various phenotypes, non-specific symptoms and variable clinical course. The occurrence of other respiratory conditions with asthma, respiratory co-morbidities (RCs), is not unusual. A literature search was performed for asthma and a variety of respiratory co-morbidities using Pub-Med for the years 2019-2024. The 5 conditions with the largest number of references, other than rhinitis and rhinosinusitis addressed in another paper in this issue, or which are the most problematic in the authors' clinical experience are summarized. Others are briefly discussed. The diagnosis and treatment of both asthma and RCs are complicated by the overlap of symptoms and signs. Recognizing RCs is especially problematic in adult onset, non-type 2 asthma as there are no biomarkers to assist in confirming non-type 2 asthma. Treatment decisions in subjects with suspected asthma and RCs are complicated by the potential similarities between the symptoms or signs of the RC and asthma, the absence of a sine quo non for the diagnosis of asthma, the likelihood that many RCs improve with systemic corticosteroids, and the possibility that the manifestations of the RCs are misattributed to asthma or vice versa. Recognition of RCs is critical to the effective management of asthma, particularly severe or difficult to treat asthma.