Acute respiratory infection (ARI) is a quite common clinical problem in daily practice. It encompasses a wide range of diseases, from “common cold”, which is mostly viral origin, with slight symptoms, and will cure rapidly without special therapy, to acute exacerbation of chronic lung disease, bothering patients with heavy symptoms and would not cure without proper therapy. Needless to say, antibiotics should not be prescribed for common cold of children and young adult. However, especially in those who are elderly or have lung comorbidity, ARI may progress to serious diseases such as pneumonia without proper treatment.
To distinct these disorders, careful history taking is essential, along with thorough physical examination. In case of positive previous history of severe disease, chest imaging such as computed tomography would be helpful to make diagnosis of lung comorbidity such as bronchiectasis or focal lung fibrosis, which often has not been diagnosed until that time. Short course fluoroquinolone is a good option to treat such patients with preexisting lung disease.