Caution. Steroids are effective medications at indiscriminately reducing inflammation. However, they have a number of potential side effects such as elevation of blood pressure/blood sugar, temporary emotional changes, gastritis and idiopathic bone necrosis. Additionally they actually suppress the natural immune system. Antibiotics, fluids, mucus thinners usually suffice unless severe airway swelling.
Acute bronchitis. Prednisone is a very powerful steroidal anti-inflammatory drug. The usual acute bronchitis, should be treated with hydration, antibiotics if bacterial, inhaled bronchodialator and possibly steroid. Prednisone is an over kill unless symptoms indicate severe airway inflammation. Prednisone will definitely improve inflammation but not the underlying infection.
Lungs. Its often helpful. It may be given with antibiotics. A chest X-ray may be needed to be sure you don't have a pneumonia.