Pneumonia causes

3 Cause of lung infection

The main pneumonia symptoms— difficulty breathing, chest pain, cough and fever — are usually the same no matter what type of pneumonia you have. But there is more than one reason for pneumonia and understanding what’s behind your illness can help doctors treat your condition effectively.


At the most basic level, pneumonia is an infection of the lungs that causes inflammation and fluid buildup in the air sacs or alveoli of the lungs, depending on the Centers for Disaster Control and Prevention (CDC). It can cause mild to severe illness in people of all ages. Although you’re more likely to get pneumonia if you’re a smoker or have underlying medical conditions like diabetes or heart disease, anyone of any age can get pneumonia, Raymond Casciari, MD, pulmonologist at Saint-Joseph Hospital in Orange, La Californie, tells Health.


Getty Images

Fortunately, pneumonia is not totally inevitable. Vaccines can help prevent some types of pneumonia, as can practicing good hand hygiene and disinfecting frequently touched surfaces. Still, pneumonia happens. In 2017, 3 million people were diagnosed with pneumonia in emergency rooms in the United States, according to data from the CDC— and that does not include people who have been diagnosed by their primary care physician.


In order to stay healthy and keep pneumonia free (at least as much as humanly possible), it helps to arm yourself with all the facts about pneumonia, and that includes what most often causes it. pulmonary infection. Here, experts explain the three main causes of pneumonia and what you need to know about each.





Bacterial pneumonia is usually caused by Streptococcus pneumonia, that lives in the upper respiratory tract, says Dr. Casciari. “It’s the most common cause of pneumonia,” he adds.


You can develop bacterial pneumonia as a complication of a viral infection, such as a cold or the flu. due to aspirating or inhaling a liquid such as saliva or vomit; or you can just develop it on your own. “Previously, the lungs were thought to be a sterile environment, devoid of bacteria. We now know that this is not true and that the lungs are ‘colonized’ by bacteria that are harmless under ordinary circumstances”, Marc A. Sala, MD, a pulmonologist and assistant professor of medicine at Northwestern Medicine, says Health. But, in certain situations, such as after a viral infection that upsets the balance of bacteria in your lungs, you can develop bacterial pneumonia, he says.


Whereas Streptococcus pneumonia is the leading cause of bacterial pneumonia, it’s not the only cause, says Dr. Casciari. Other types of bacteria known to cause pneumonia, according to the US National Library of Medicine’s MedlinePlus resource, include:


  • Legionella pneumophila (pneumonia caused by this bacteria is better known as Legionnaires’ disease)
  • Mycoplasma pneumoniae
  • Chlamydia pneumoniae
  • Haemophilus influenzae


Bacterial pneumonia is usually treated with oral antibiotics, says Dr. Casciari. But, in more severe cases, a patient may receive IV antibiotics, breathing treatments, or oxygen therapy, MedlinePlus said. Also note, according to the CDC: The pneumococcal vaccine can help reduce your risk of getting bacterial pneumonia Streptococcus pneumonia.





Many viruses can cause viral pneumonia. Respiratory syncytial virus (RSV) is the most common cause of pneumonia in children, but influenza virus and SARS-CoV-2, the virus that causes COVID-19[feminine], are the leading causes of pneumonia in adults, says Dr. Casciari. MedlinePlus states that the common cold also has the potential to cause pneumonia.


“The typical way one develops pneumonia is by being exposed to droplets or aerosols from someone who has an active infection, leading to inflammation and an immune response, which we then call pneumonia,” says Dr Sala. Viral pneumonias can also have a secondary bacterial infection, says Dr. Casciari.


Treatment for viral pneumonia usually involves the use of antiviral therapy such as oseltamivir (Tamiflu) or remdesivir, says Dr. Casciari. And just like with bacterial pneumonia, people with severe cases may need supplemental oxygen or breathing treatments.


Certain vaccines can help lower your risk of developing viral pneumonia, including the flu vaccine and the COVID-19 vaccine, says Dr. Casciari.





Fungal pneumonia is more of a potential problem for people with chronic health complications or a weakened immune system. Nicola Hanania, MD, a pulmonologist at Baylor College of Medicine, says Health that doctors “don’t really see fungal pneumonia in people with normal immune systems.” But for people with diabetes, AIDS, HIV or cancer, it can be a risk, she says.


“Overall, fungal pneumonia is not a problem for most people in the United States except for a few organizations,” adds Dr. Sala. The most common fungal infections linked to pneumonia, according to MedlinePlus, include:


  • Pneumocystis pneumonia (PCP), caused by the fungus Pneumocystis jiroveci
  • Valley fever or coccidioidomycosis, caused by the fungus Coccidioides
  • Histoplasmosis, caused by the fungus Histoplasma
  • Cryptococcosis, caused by fungi Cryptococcus neoformans and Cryptococcus gattii


With fungal pneumonia, people often become infected when they breathe in certain fungal spores, says Dr. Casciari. Doctors usually treat fungal pneumonia with antifungal medications like fluconazole.


If you have any of the common signs of pneumonia — fever, chills, cough and shortness of breath, among others — doctors say it’s important to seek treatment no matter what might be behind it. “Pneumonia is serious,” says Dr. Casciari. “It can be deadly.”


To get our best stories delivered to your inbox, subscribe to Healthy lifestyle newsletter