A cough that has been present for more than a month is clinically known as a subacute cough, also known as a migratory cough, and is considered to have an effect on the lungs. This is because the common cause of cough is a lung infection followed by a gradual increase in lung inflammation with a tendency to deteriorate, such as the formation of a significant lung abscess or even a tendency to different chronic pneumonia in the lungs, which may lead to a decrease in lung function. Then there are recurrent episodes of cough variant asthma, where the airways become hyper-reactive due to allergens, which can easily lead to a continuous decrease in respiratory function and even cause chronic respiratory failure.