Pneumocystis Jiroveci Pneumonia: Causes, Symptoms, and Treatment
Medically reviewed by Harsha Moole, MD, Internal Medicine. Last reviewed: October 2, 2026.
What kind of doctor treats Pneumocystis Jiroveci Pneumonia?
A pulmonologist, a doctor who specializes in lung diseases, usually treats this infection. Many people first see their primary care doctor, who can start testing and bring in the right specialists. A direct primary care or concierge doctor can be a first stop for an evaluation and can refer you to a specialist when needed.
What is Pneumocystis Jiroveci pneumonia?
Pneumocystis Jiroveci pneumonia is a lung infection caused by a tiny germ that most people carry without ever getting sick. It mainly affects people with weakened immune systems. The infection makes it hard to breathe and can be serious without treatment.
Pneumocystis Jiroveci pneumonia, often called PJP or PCP, is an infection that fills the air sacs of the lungs with fluid and debris. The germ is a fungus that many healthy people carry without ever knowing. Problems start when the immune system becomes weak from illness or medicine.
Symptoms
Symptoms usually come on slowly over days or weeks: fever, a dry cough, and shortness of breath that gets worse with activity. Some people feel very tired or lose weight without trying. If you have trouble breathing, you need medical care right away.
Causes and who gets it
The cause is the fungus Pneumocystis Jiroveci, which lives in the lungs of many people without causing harm. People at higher risk include those with untreated HIV, people getting cancer treatment, and people taking medicines that lower the immune system after an organ transplant.
How doctors diagnose it
Doctors start by asking about symptoms and doing a physical exam. They often order a chest X-ray and a blood test that measures oxygen levels. To confirm the infection, doctors look for the germ in a sample from the lungs, taken from coughed-up mucus or through bronchoscopy.
Treatment
Treatment uses antibiotic medicines that kill the fungus. The most common one is trimethoprim and sulfamethoxazole, known by the brand name Bactrim. People with low oxygen may also get a steroid to reduce swelling in the lungs. Treatment usually lasts several weeks.
When to see a doctor
Call a doctor if you have a cough, fever, or shortness of breath that does not go away, especially if something weakens your immune system. Get emergency care for severe trouble breathing, chest pain, or confusion. Early treatment usually leads to better results.
How a direct primary care or concierge doctor fits in
A direct primary care doctor charges a flat monthly fee instead of billing insurance, while a concierge doctor usually charges more and often works alongside insurance. These doctors often have longer visits, making it easier to discuss symptoms and risk factors. They can order chest X-rays and blood tests, start early treatment, and refer you to a pulmonologist if needed.
Common questions
Is Pneumocystis pneumonia contagious?
Not in the usual sense. Most people who get it already carry the germ, and it flares up only when the immune system is weak. It does not spread like the flu or a cold.
Can healthy people get it?
It is rare in people with normal immune systems. When it does appear in otherwise healthy people, it is usually mild.
Does it come back after treatment?
It can come back if the immune system stays weak. Doctors often prescribe a preventive medicine for people at high risk.
How long does treatment take?
Treatment commonly lasts about three weeks. Your doctor will decide the exact length based on how sick you are and how you respond.
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Medical Disclaimer
This content is for general educational and informational purposes only and is not medical advice. It is not a substitute for professional medical advice, diagnosis, or treatment, and reading it does not create a doctor-patient relationship. Always seek the advice of your physician or another qualified health provider with any questions about a medical condition, and never disregard or delay seeking professional advice because of something you read here. If you think you may have a medical emergency, call 911 (or your local emergency number) immediately.
