Pneumonia CAN cause asthma. 

The question of whether pneumonia causes asthma or not depends completely on the type of bacteria resulting in infection. Many bacterium that result in the development of pneumonia do not cause asthma. The bacteria that causes "walking pneumonia" called mycoplasma pneumoniae has been linked to an increase in asthma in many patients.

Organisms Causing Pneumonia

More than 30 microorganisms are known to cause pneumonia. After a diagnosis of pneumonia, doctors test the microorganism to determine the type of pneumonia and appropriate treatment method. The three most common organisms to cause pneumonia include the influenza virus, streptococcus pneumoniae bacteria and respiratory syncytial virus. These require antibiotic treatments to eliminate. Mycoplasma pneumoniae bacteria does not require antibiotics and eventually heals without treatment.

Mice Show Links to Asthma

New studies have shown that patients who develop "walking pneumonia" from mycoplasma pneumoniae continue to have restriction in the bronchial tubes months and even years after the infection has healed. After seeing a common trend, researchers infected lab mice to determine whether asthma develops or not. The results showed that after 18 months without the infection, the mice developed bronchial restriction resulting in asthma.

Pulmonary Testing

Medical testing of patients who have healed from mycoplasma pneumoniae infections in the lungs has shown pulmonary abnormalities that remain after the infection completely clears. The doctors ran tests three months after the infection was healed and again three years later. The resulting abnormalities remained similar between three months and three years, suggesting that an infection resulting in walking pneumonia causes asthma in some patients.