Types of Pneumonia

Pneumonia is named for the way in which a person gets the infection or for the germ that causes it.

Community-Acquired Pneumonia

Community-acquired pneumonia (CAP) occurs outside of hospitals and other health care settings. Most people get CAP by breathing in germs (especially while sleeping) that live in the mouth, nose, or throat.

CAP is the most common type of pneumonia. Most cases occur during the winter. About 4 million people get this form of pneumonia each year. About 1 out of every 5 people who has CAP needs to be treated in a hospital.

Hospital-Acquired Pneumonia

Some people catch pneumonia during a hospital stay for another illness. This is called hospital-acquired pneumonia (HAP). You’re at higher risk for getting HAP if you’re on a mechanical ventilator (a machine that helps you breathe).

HAP tends to be more serious than CAP. This is because you’re already sick. Also, hospitals tend to have more germs that are resistant to antibiotics—a treatment for pneumonia.

Health Care-Associated Pneumonia

Patients also may get pneumonia in other health care settings, such as nursing homes, dialysis centers, and outpatient clinics. This is called health care-associated pneumonia.

Other Common Types of Pneumonia

Aspiration Pneumonia

This type of pneumonia occurs when you accidentally inhale food, drink, vomit, or saliva from your mouth into your lungs. This usually happens when something disturbs your normal gag reflex, such as a brain injury, swallowing problem, or excessive use of alcohol or drugs.

Aspiration pneumonia can cause pus to form in a cavity in the lung. This is called a lung abscess.

Atypical Pneumonia

Several types of bacteria—Legionella pneumophila, mycoplasma pneumonia, and Chlamydophila pneumoniae—cause this type of CAP. Atypical pneumonia is passed from person to person.