The Most Common Causes of Pneumonia

There are more than 30 pneumonia-causing germs.

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Pneumonia is a common infection that causes the air sacs (alveoli) in the lungs to fill with fluid or pus. With the proper treatment, most healthy people recover from pneumonia within a few weeks, but it can be life-threatening for some.

Tens of thousands of people in the U.S. die from pneumonia every year, most of them adults over the age of 65, according to the American Lung Association. That’s why it’s important to be aware of the symptoms of pneumonia and what type you may have, so you can get the proper treatment as soon as possible.

The Main Types of Pneumonia

In general, the types of pneumonia are categorized based on the germ that caused it: a type of bacteria, virus, or fungi. These germs can be spread via coughing, sneezing, touching, and even breathing. 

Bacterial pneumonia tends to be more serious than other forms, and can come on gradually or suddenly. The most common type is called pneumococcal pneumonia, which is caused by the bacteria Streptococcus pneumoniae that normally lives in the upper respiratory tract. 

Bacterial pneumonia can occur on its own or piggyback off a cold or flu. It can cause a dangerous fever (as high as 105 degrees), rapid pulse rate, bluish lips or nail beds, and confusion. Bacterial pneumonia may also lead to severe complications.

Viral pneumonia is caused by a virus. In adults, the most common pneumonia-causing virus is the influenza virus (psst … that’s the flu). In children, it’s the respiratory syncytial virus (RSV), a common virus that causes respiratory infections. 

Viral pneumonia often develops over a period of several days. It can cause symptoms such as fever, a dry cough, headache, muscle pain, and weakness. Most viral pneumonias are not serious and last a shorter time than bacterial pneumonia. However, viral pneumonia caused by the influenza virus can be serious and sometimes fatal. The virus invades the lungs and multiplies, but there are often no signs of the lung tissue filling with liquid. 

Fungal pneumonia is caused by certain types of fungi, such as Coccidioidomycosis (valley fever), Histoplasmosis, and Cryptococcus. It’s most common in people with weakened immune systems or chronic health problems, as well as people who are exposed to soil or bird droppings that are contaminated with pneumonia-causing fungi. 

Symptoms of fungal pneumonia may include fever, cough, headache, rash, muscle aches, or joint pain. 

If you even have a slight suspicion that you or someone you know has pneumonia, don’t wait to see if the condition gets worse. Call a doctor as soon as possible—especially if you or a loved one is at high-risk for severe pneumonia.

Most cases of pneumonia can be treated successfully, but the sooner you get treatment, the better.