Although infection is not the reason or cause of chronic bronchitis, it is seen to aid in sustaining the bronchitis. Diagnosis
A physical examination will often reveal decreased intensity of breath sounds, wheezing, rhonchi, and prolonged expiration. During examination for physicians rely on history and the presence of persistent or acute onset of cough, followed by a URTI with no traces of pneumonia. Acute bronchitis is typically a clinical diagnosis that relies on patients history and exam, and should be suspected in patients with an acute onset of cough, which often follows a URTI without traces of pneumonia.Although there is no universally-accepted clinical definition for acute bronchitis, there is a proposed set of practical criteria (Macfarlane, 2001) that include:

An acute illness of less than three weeks. Cough as the predominant symptom. At least one other lower respiratory tract symptom, such as sputum production, wheezing, chest pain. No alternative explanation for the symptoms.A variety of tests may be performed in people presenting with cough and shortness of breath:
A chest X-ray is useful to exclude pneumonia which is more common in those with a fever, fast heart rate, fast respiratory rate, or who are old. A sputum sample showing neutrophil granulocytes (inflammatory white blood cells) and culture showing that has pathogenic microorganisms such as Streptococcus species. A blood test would indicate inflammation (as indicated by a raised white blood cell count and elevated C-reactive protein).Decreased breath sounds, crackles, wheezing, and rhonchi that clears with coughs may be heard in the chest.
Acute bronchitis, also known as a chest cold, is short-term bronchitis – inflammation of the bronchi (large and medium-sized airways) of the lungs. The most common symptom is a cough. Other symptoms include coughing up mucus, wheezing, shortness of breath, fever, and chest discomfort. The infection may last from a few to ten days. The cough may persist for several weeks afterward with the total duration of symptoms usually around three weeks. Some have symptoms for up to six weeks.In more than 90% of cases, the cause is a viral infection. These viruses may be spread through the air when people cough or by direct contact. Risk factors include exposure to tobacco smoke, dust, and other air pollution. A small number of cases are due to high levels of air pollution or bacteria such as Mycoplasma pneumoniae or Bordetella pertussis. Diagnosis is typically based on a persons signs and symptom. The color of the sputum does not indicate if the infection is viral or bacterial. Determining the underlying organism is typically not needed. Other causes of similar symptoms include asthma, pneumonia, bronchiolitis, bronchiectasis, and COPD. A chest X-ray may be useful to detect pneumonia.Prevention is by not smoking and avoiding other lung irritants. Frequent hand washing and flu vaccination may also be protective. Treatment of acute bronchitis typically involves rest, paracetamol (acetaminophen), and NSAIDs to help with the fever. Cough medicine has little support for its use and is not recommended in children less than six years of age. Antibiotics should generally not be used.