HIV-Related Pneumocystis Pneumonia (PCP)
Last updated: November 2020
Pneumocystis pneumonia (PCP) is a lung infection caused by the fungus Pneumocystis jirovecii. PCP is most often seen in people who have weakened immune systems due to disease, medication, or an organ transplant.
How common is pneumocystis pneumonia?
It is particularly common in people living with HIV/AIDS.1 PCP was rare before the 1980s, but the number of cases increased as the HIV/AIDS epidemic progressed. Now, PCP cases have dropped since doctors have been able to prescribe long-term preventative treatment for people living with HIV/AIDS.
Currently, PCP is most often seen in people who do not know they have acquired HIV. Often, being diagnosed with PCP results in testing and confirmation of an HIV diagnosis. Though PCP is less common today, it is still the most common opportunistic infection among those living with HIV.2
How is PCP related to HIV?
PCP is considered an opportunistic infection. This means that it is most likely to affect individuals with weakened immune systems. PCP usually develops in people who are HIV positive when their CD4+ cell count is low, 200 cells/mm3 or less. CD4+ cells are white blood cells that defend the body from infection.2 HIV kills CD4+ cells. Without CD4+ cells, the body has less defense against infection.
How is PCP transmitted?
The fungus that causes PCP can also be found in people who are not HIV positive. These individuals do not have symptoms because their immune system is able to control the amount of fungus.
Researchers currently believe that PCP infections in individuals with HIV are caused by exposure in the air. The fungus is exhaled into the air from another person who is infected with the fungus. Because of this, PCP can be transmitted easily in a hospital or healthcare setting.2
What are the symptoms of PCP?
PCP can often look like other lung infections. The symptoms of PCP include:1
- Dry cough
- Difficulty breathing
- Chest pain
- Fatigue (tiredness)
For most individuals living with HIV, these symptoms develop slowly over several weeks. Their fever also remains mild. Individuals who have weakened immune systems due to reasons other than HIV/AIDS develop symptoms quickly and experience high fevers.1
Getting a PCP diagnosis
It is important to correctly diagnose PCP so that the right treatment is given. The most common method to diagnose PCP is a sputum collection. The physician asks the patient to cough up sputum (mucus). It is collected and sent to the lab to be examined.
How is PCP treated?
PCP must be treated with prescription antibiotics. If left untreated, the infection may become fatal. The most common antibiotic used is trimethoprim/sulfamethoxazole (TMP/SMX). This drug is usually given for 3 weeks either in a pill form or through an IV.
Some people may develop a rash, fever, or allergic reaction after taking TMP/SMX. Other antibiotics are used in these situations.1
Prevention of pneumocystis pneumonia
With the rise of HIV/AIDS in the late 1980s, the number of PCP cases jumped drastically. It was estimated that 75 percent of people living with AIDS developed PCP during that time.1 Today, individuals living with HIV are often treated with antiretroviral therapy and are prescribed TMP/SMX as a long-term preventative treatment.1 Because of this, PCP cases are much less frequent.
PCP is still a major health concern for people living with HIV because it can be fatal.1 Because it is most likely to infect people with weakened immune systems, it is important to follow good hygiene practices.
If you think you may have PCP, contact your healthcare provider to be tested.