Classifying an upper respiratory infection as bronchitis is imprecise. However, studies of bronchitis and upper respiratory infections often use the same symptoms. Cough is the most commonly observed symptom of acute bronchitis. The cough begins within two days of infection in 85 percent of patients. Most patients have a cough for less than two weeks however, 26 percent are still coughing after two weeks, and a few cough for six to eight weeks. When a patient's cough fits this general pattern, acute bronchitis should be strongly suspected.
Although most physicians consider cough to be necessary to the diagnosis of acute bronchitis, they vary in additional requirements. Other signs and symptoms may include sputum production, dyspnea, wheezing, chest pain, fever, hoarseness, malaise, rhonchi, and rales. Each of these may be present in varying degrees or may be absent altogether. Sputum may be clear, white, yellow, green, or even tinged with blood. Peroxidase released by the leukocytes in sputum causes the color changes; hence, color alone should not be considered indicative of bacterial infection.
Because acute bronchitis is most often caused by a viral infection, usually only symptomatic treatment is required. Treatment can focus on preventing or controlling the cough (antitussive therapy) or on making the cough more effective.
Protrusive therapy is indicated when coughing should be encouraged (e.g., to clear the airways of mucus). Antitussive therapy is indicated if cough is creating significant discomfort and if suppressing the body's protective mechanism for airway clearance would not delay healing.