Paroxysmal Nocturnal Hemoglobinuria: Causes, Symptoms, and Treatment
Medically reviewed by Harsha Moole, MD, Internal Medicine. Last reviewed: October 23, 2026.
What kind of doctor treats Paroxysmal Nocturnal Hemoglobinuria?
A hematologist, a doctor who treats blood diseases, usually leads care for paroxysmal nocturnal hemoglobinuria (PNH). A primary care doctor can help find the problem and coordinate your care. 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 paroxysmal nocturnal hemoglobinuria?
Paroxysmal nocturnal hemoglobinuria (PNH) is a rare disease in which red blood cells break down earlier than normal. PNH is estimated to affect between 1 and 5 per million people.
People with PNH have sudden, recurring episodes of symptoms. The word paroxysmal refers to these episodes. Hemoglobin is the oxygen-carrying protein in blood. When it shows up in the urine, the condition is called hemoglobinuria. In many, but not all cases, this is most noticeable early in the morning. That is the nocturnal part of the name.
Symptoms
Symptoms may include:
- Dark urine that comes and goes.
- Weakness and tiredness (fatigue).
- Pale skin and shortness of breath.
- Headache and back pain.
- Belly pain.
- Easy bruising or bleeding.
- Blood clots, which may form in some people.
People with PNH may also get infections more easily because of a shortage of white blood cells.
Causes and who gets it
Changes in a gene called PIGA cause almost all cases of PNH. These changes happen during a person's lifetime in a blood-forming cell in the bone marrow. They are not inherited. PNH is acquired, not inherited. It is not passed down to children of affected people.
Two proteins on red blood cells normally protect them from being broken down by the immune system. Without these proteins, the abnormal red blood cells are destroyed too soon. PNH may be linked to aplastic anemia, a condition in which the bone marrow does not make enough blood cells. People with PNH are at increased risk of leukemia, a cancer of the blood-forming cells.
How doctors diagnose it
Doctors may suspect PNH when a person has signs of red blood cell breakdown with no known cause. One example is hemoglobin in the urine. The main test for suspected PNH is flow cytometry. This is a blood test that can identify PNH cells.
Other tests that may be done include a complete blood count (CBC) and a lactate dehydrogenase (LDH) test.
Treatment
Treatment is directed at the symptoms each person has. Soliris (eculizumab) and Ultomiris (ravulizumab) are medicines used to treat PNH. They block the breakdown of red blood cells. Eculizumab does not cure PNH, but it can reduce the risk of blood clots and improve quality of life. Eculizumab raises the risk of a serious infection called meningococcal infection, so patients must be vaccinated first. Follow your doctor's instructions about vaccines.
Newer medicines are also approved for adults with PNH. They include pegcetacoplan (Empaveli) and iptacopan (Fabhalta), the first pill for PNH. Blood transfusions may be needed. Blood thinners may be used to prevent clots. They must be strictly managed because of the risk of too much bleeding. People with severe bone marrow failure may be treated with medicines that calm the immune system.
A bone marrow transplant is the only curative therapy for PNH. In this treatment, damaged bone marrow is replaced with healthy marrow from a donor. Because of the risks, it is saved for people with serious problems, such as severe bone marrow failure or repeated, life-threatening blood clots. Everyone with PNH should get vaccines against certain bacteria to prevent infection. Ask your health care provider which ones are right for you.
When to see a doctor
Call 911 or go to the emergency room if you have chest pain that lasts two minutes or more, severe trouble breathing, fainting, a sudden change in mental state, severe belly pain, or sudden weakness or trouble speaking. Blood clots are a risk with PNH, and clots can cut off blood flow to vital organs. If you take eculizumab or ravulizumab, also get emergency care right away for a fever, a stiff neck, or a bad headache, because these medicines raise the risk of a serious infection called meningococcal infection.
Contact your provider if you find blood in your urine, if symptoms worsen or do not improve with treatment, or if new symptoms develop.
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. A direct primary care doctor can order first blood tests and help you reach a hematologist. After a diagnosis, this doctor can help keep track of your overall health between specialist visits.
Common questions
Is paroxysmal nocturnal hemoglobinuria inherited?
No. PNH is acquired, not inherited. Most cases come from new changes in the PIGA gene and generally occur in people with no family history of the disorder.
Can PNH be cured?
Yes, but only with a bone marrow transplant, which is the only curative therapy for PNH. Medicines such as eculizumab do not cure PNH, but they can reduce the breakdown of red blood cells and the risk of blood clots.
Why does PNH cause dark urine?
The red blood cells break down too early and leak hemoglobin into the blood, which can pass into the urine. This can happen at any time, but is more likely to occur during the night or early morning.
Does PNH raise the risk of blood clots?
Yes. People with PNH may have abnormal blood clotting, especially in large abdominal veins. Blood thinners may be needed to prevent clots from forming.
Sources
- MedlinePlus Genetics - Paroxysmal nocturnal hemoglobinuria
- MedlinePlus - Paroxysmal nocturnal hemoglobinuria (PNH)
- National Organization for Rare Disorders - Paroxysmal Nocturnal Hemoglobinuria
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.
