Pneumocystis pneumonia (PCP) is a form of pneumonia. It affects people who have a weakened immune system. PCP is the most common serious infection among people with AIDS.
The Lungs (Cut-away View)
PCP is caused by a fungus. Most believe that the fungus is spread in the air, but it is not clear if the fungus lives in soil or elsewhere. In healthy people, the fungus can exist in the lungs without causing pneumonia. However, in people who have a weakened immune system, the fungus can spread and cause a lung infection.
A weakened immune system can put you at risk for PCP. The immune system may be weakened in people who:
- Have AIDS
- Have cancer
- Are getting treatment for cancer
- Are using medications that may weaken the immune system, such as steroids
- Have a history of PCP infection
Symptoms of PCP usually develop over the course of a few weeks or months. The main symptoms of PCP are:
- Shortness of breath
- Dry cough
- Tightness or pain in the chest
See your doctor immediately if you have any these symptoms.
Your doctor will ask about your symptoms and medical history. To confirm PCP, a sample of mucus from your lungs will be examined under the microscope. Your doctor will collect samples by giving you either:
- A vapor treatment to make you cough
- A bronchoscopy
Treatment depends on the severity of the infection. This may include:
- Oral or IV medications—anti-infectious agents and corticosteroids
- Supportive treatments to help with breathing
Even when treatment is given for PCP, the death rate is 15% to 20%.
PCP infections can cause damage to your lungs and affect your overall health. Preventing a PCP infection is an important first step. A healthy immune system is the best prevention for PCP. See your doctor as recommended to help monitor your immune system. If you have HIV, follow your treatment program to keep your immune system healthy. This will help prevent a PCP infection.
If you are at risk for PCP, your doctor may recommend that you take medication to prevent getting it. Take preventative medication as recommended, do not skip doses. PCP prevention with medication may be recommended if:
- You have HIV and your CD4 cell count falls below 200.
- You plan to use immune suppressing medications for a long period of time.
- You have other conditions such as a temperature above 100˚F that lasts for more than 2 weeks, or a fungal infection in your mouth or throat.
Talk to your doctor about a pneumonia vaccine. This only protects you from a different kind of pneumonia. It will not prevent you from getting PCP.
AIDS info—National Institutes of Health
Centers for Disease Control and Prevention
Canadian Health Network
Canadian HIV/AIDS Information Centre
Pneumocystis pneumonia. Centers for Disease Control and Prevention website. Available at: http://www.cdc.gov/fungal/diseases/pneumocystis-pneumonia/index.html. Accessed May 20, 2013.
Pneumocystis pneumonia (PCP). Dynamed website. Available at: http://www.ebscohost.com/dynamed. Updated March 4, 2012. Accessed May 20, 2013.
Wilkin A, Feinberg J. Pneumocystis carinii pneumonia. Am Fam Physician. 1999;15(60):1699-1708.
Last reviewed February 2015 by David L. Horn, MD
Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.