Pneumocystis Pneumonia

Many people live with the fungus Pneumocystis jiroveci in their lungs every day. Most of the time, the organism causes little to no trouble for people with a healthy and strong immune system.

But if your immune system is weakened by HIV/AIDS, cancer, or another condition, you have a greater chance of developing pneumocystis pneumonia (PCP). PCP is a crippling lung infection that's related to the fungus.

If you are HIV-positive, PCP is an opportunistic infection. This means that PCP takes advantage of your weakened immune system to attack. If you develop PCP, your HIV infection has turned into AIDS. But effective treatments are available for both illnesses.

Treatment is a must. If not treated right away, PCP can be severe and even fatal. It is the most common serious infection in the U.S. among people who have advanced HIV disease. It is also a leading cause of death among people who have AIDS. Fortunately, the disease is less common here than it used to be, but when it occurs, it requires immediate medical attention.


If you have advanced HIV disease, the symptoms of PCP may develop over a period of weeks or months. Watch for:

  • Sudden onset of fever

  • Cough

  • Difficulty breathing, especially with exercise

  • A dry cough, with little or no production of mucus

  • Chest tightness

  • Weight loss

  • Night sweats


If you experience any of the above symptoms and believe that you might have PCP, see your doctor immediately. Usually, your doctor can correctly diagnose PCP through an X-ray, a sample of lung fluids or tissue, and other common tests.


If you have HIV and get a severe pneumocystis pneumonia infection, you will likely be treated in a hospital with medicine given through an IV. The common medication given for PCP is trimethoprim-sulfamethoxazole, also called TMP-SMX. If you can't take that medication, other drugs are available to treat the condition. As you improve, you will likely be able to switch to a medication in a pill form.


Most people with diagnosed HIV are put on medication to prevent the disease before it occurs. This is the reason there has been a decrease in the incidence of PCP in recent years.

If you have HIV, your doctor will likely check your blood count regularly in order to determine the strength of your immune system. If your blood cell count known as CD4 drops below 200, your doctor will likely put you on a course of TMP-SMX to prevent PCP from occurring.

Even with a CD4 count between 200 and 300, you may be given this medication if you've had your spleen removed, or if your doctor sees signs that your immune system is getting weaker. Signs of this could be recurring fevers or fungal infections, including a fungal infection in the mouth known as thrush.

Pregnant women with HIV sometimes have a drop in their CD4 count during the third trimester. If you have HIV and are pregnant, your doctor may recommend that you take medicine to ward off PCP at that stage of your pregnancy.

Smokers are also thought to be at a greater risk of developing the disease. If you smoke, quitting will improve the health of your lungs and help you fend off lung infections like PCP.

The fungus that causes PCP is common all over the world. Researchers believe it might be spread through the air or soil. For this reason, your best approach to preventing the disease if you have HIV is to stay vigilant about getting regular blood tests and to take preventive medications if appropriate.