What is typically the cause of acute bronchitis?

Acute bronchitis is most commonly caused by infections, primarily due to viruses or bacteria. Viral infections, such as those that cause upper respiratory tract infections, are responsible for the majority of cases. The inflammation of the bronchial tubes occurs as a response to the infectious agents, leading to symptoms like cough, mucus production, and difficulty breathing.

While exposure to allergens and environmental toxins can contribute to respiratory issues and chronic conditions, they are not the primary causes of acute bronchitis. Long-term smoking does lead to chronic bronchitis, which is a different condition characterized by persistent cough and mucus production, but it does not represent the acute onset of bronchial inflammation associated with acute bronchitis. Thus, the focus on viral and bacterial infections aligns with the most common etiology of the condition.