What Is It?

Pneumonia is an infection of the lungs. Most pneumonias are caused by bacterial infections, and the most common cause in the United States is the bacteria Streptococcus pneumoniae. Other bacteria, such as Mycoplasma and Legionella, as well as certain viruses, also can cause pneumonia. However, because these less common infections do not always cause all of the classic pneumonia symptoms, they often are called atypical pneumonias. Atypical pneumonias most commonly occur in people under age 40.

Pneumonia that develops when someone is hospitalized for another illness tends to be more serious, because the organisms found in a hospital have become resistant to many antibiotics. Also, because you are hospitalized, you are apt to be weakened by your other illnesses and less able to fight off the infection.

A type of pneumonia called aspiration pneumonia develops when chemical irritants and bacteria from the mouth or stomach are inhaled into the lungs. It is more common in people who have had strokes and have difficulty controlling their swallowing reflexes or people who are unconscious as a result of alcohol or other drug overdoses.


Most pneumonias cause fever, cough with sputum (coughed-up mucus), shortness of breath and fatigue. In older patients, fatigue or confusion can be the only or most noticeable symptoms. In atypical and viral pneumonias, a dry cough without sputum is more common.


Your doctor first will ask about your symptoms. During the physical exam, your doctor will check to see if you are breathing rapidly. He or she also will look for confusion and a purplish hue in your lips, fingernails or hands because these can indicate that you have low levels of oxygen in your blood. Using a stethoscope, your health-care provider can listen through your back for abnormal sounds from the lungs. The diagnosis of pneumonia most often is confirmed by an X-ray. If the chest X-ray does not show pneumonia, but your symptoms and physical exam suggest pneumonia, your doctor may make the diagnosis by looking at sputum (coughed-up mucus) under a microscope or checking if a blood test shows an elevation of infection-fighting white blood cells. Samples of your sputum or blood also can be sent to a laboratory to identify the specific cause of your pneumonia. Identifying the infectious organism can help your doctor to choose the best antibiotic to treat the infection. However, even when no organism can be identified, the pneumonia still can be treated successfully with antibiotics.

Expected Duration

How long pneumonia lasts can vary from a few days to a week or longer, depending on how early a person starts antibiotics and what other medical problems he or she may have. Antibiotic treatment for pneumonia usually lasts from 10 to 14 days. Many people find that it takes a few weeks to several weeks to regain the level of energy they had before the pneumonia.


There are two vaccines that can prevent the development of pneumonias. A vaccine against some of the common types of Streptococcus pneumonia (pneumococcal polysaccharide vaccine, or PPV) is recommended for people over the age of 65 and for people at higher risk of developing serious pneumonia. This includes people with:

  • Lung disease
  • Heart disease
  • Liver disease
  • Kidney disease
  • A damaged spleen or no spleen
  • Certain types of cancer or people undergoing cancer treatment
  • A weakened immune system

Another type of pneumonia vaccine (pneumococcal conjugate vaccine — PCV) is given to children under the age of 2. While it is used mostly to reduce the risk of meningitis and ear infections, it also lowers the risk of pneumonia.

The influenza vaccine, which is given annually, effectively reduces both the incidence of influenza and subsequent bacterial infections or pneumonia that can complicate the initial viral infection. Anyone over the age of 6 months can have the vaccine. It is strongly recommended for people over the age of 65, and the following people who are at higher risk of developing serious influenza:

  • Residents of nursing homes and other long-term health care facilities
  • Anyone with chronic lung or heart lung disease
  • Anyone who has been hospitalized within the past year for chronic medical problems
  • Anyone with a weakened immune system due to HIV/AIDS, cancer or certain medications (such as prednisone or cancer chemotherapy)
  • Women who will be past the third month of pregnancy during the influenza season (November through April)
  • Children and adolescents on long-term aspirin therapy (because of the risk of Reye’s syndrome)

The influenza vaccine also is recommended for adults between the ages of 50 and 65, children between the ages of 6 and 23 months and people who are in close contact with someone at high risk, including parents, household and day-care contacts of young children, health-care workers and employees of long-term and assisted-living facilities.

For the 2003-2004 season, a new nasal influenza vaccine called FluMist is available. It is a live, weakened form of the virus that doesn’t require an injection, but is inhaled. It has initially been approved for use in healthy people between the ages of 5 and 50.


The main treatment for pneumonia is an antibiotic. A younger or healthier person can be treated safely with antibiotics at home and can feel better in a few days. Some people are at higher risk of complications and may need to be hospitalized for two days to a week. They include people who are older than 60 or have other diseases such as congestive heart failure, chronic kidney disease or chronic obstructive pulmonary disease (COPD); a high white-blood-cell count; or a low oxygen level in the blood.

In addition to antibiotics, other treatments for pneumonia include: rest, adequate fluids and supplemental oxygen to raise the level of oxygen in the blood. Coughing is important because it helps to clear infected material from the lungs, so your doctor may not want to give you medication to suppress your cough completely. If your pneumonia is severe, you may be placed on a mechanical ventilator to get enough oxygen into your blood.

When To Call A Professional

A simple cold or bronchitis caused by a virus can share many of the same symptoms as pneumonia. Pneumonia is possible when your cough produces sputum with a green or brown color, you are having shaking chills or you are having trouble breathing. Shortness of breath may mean that pneumonia is developing, or that the breathing tubes are going into spasm and making it harder to breathe. In these cases, you should call your doctor for an urgent evaluation.

Also, if you have been diagnosed with a cold or bronchitis and symptoms are getting worse or persist after a week, you should call your doctor’s office for another evaluation.


Most pneumonias are treated successfully, especially if antibiotics are started early. Pneumonia can be fatal, but usually only when it is not diagnosed until it is severe, or when it develops in people with many other medical problems.

Pneumonia usually does not cause permanent damage to the lungs. In rare cases, aspiration pneumonia may develop into a lung abscess, called an empyema.

Johns Hopkins patient information

Last revised:

Diseases and Conditions Center

  A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z

All ArmMed Media material is provided for information only and is neither advice nor a substitute for proper medical care. Consult a qualified healthcare professional who understands your particular history for individual concerns.