Polycythemia vera facts for kids
Polycythemia vera (PV) is a rare blood condition where the bone marrow makes too many red blood cells. The bone marrow is the spongy center inside bones where blood cells are made. When there are too many red cells, the blood becomes thicker. This can make it harder for blood to flow through the body.
Most people with this condition have a specific change, or mutation, in a gene called JAK2. This gene helps control how blood cells are made. This condition is considered a type of myeloproliferative neoplasm, which means it involves rapid growth of blood cells.
Doctors treat PV by helping to thin the blood. This is often done by removing small amounts of blood or using medicine. With proper care, people with PV can live for many years.
Contents
What Causes Polycythemia Vera?
The JAK2 Gene
Inside the body's cells, genes act like instruction manuals. In about 98% of people with PV, there is a mutation in the JAK2 gene. This gene normally acts like an on/off switch for making blood cells.
In people with PV, the mutation makes the switch get stuck in the "on" position. This causes the body to keep making red blood cells even when it does not need them. This is different from other types of polycythemia where the body makes more red cells because of low oxygen or other reasons.
How It Affects the Body
Normally, a hormone called erythropoietin (EPO) tells the body when to make more red blood cells. In PV, the cells grow on their own without waiting for the EPO signal. Because of this, people with PV usually have very low levels of EPO in their blood.
Signs and Symptoms
Common Symptoms
Some people with PV do not feel sick at all. Doctors might find it during a routine blood test. When symptoms do happen, they can include:
- Itching (Pruritus): This is very common. It often happens after a warm bath or shower. About 40% to 55% of patients experience this.
- Skin Changes: The face or skin might look reddish. Sometimes, the skin can look bluish because of slow blood flow.
- Burning Pain: A condition called erythromelalgia can cause burning pain in the hands or feet. The skin may turn red or blue. This happens because sticky blood cells (platelets) clump together in small blood vessels. Aspirin often helps stop this pain.
- Fatigue: Feeling very tired is a common complaint.
- Night Sweats: Sweating a lot while sleeping.
Other Health Issues
People with PV might have other conditions related to the disease:
- Enlarged Spleen: The spleen is an organ that filters blood. It can get bigger because it is working hard to handle the extra blood cells.
- Joint Pain: A condition called Gout can cause swollen and painful joints.
- Stomach Issues: Some people may develop peptic ulcers.
Diagnosis
How Doctors Test for PV
Doctors use specific rules to diagnose PV. According to guidelines from 2016 and updates through 2025, doctors look for three main things:
- High Red Blood Cell Count: Tests show high levels of hemoglobin (the protein that carries oxygen) or hematocrit (the amount of space red cells take up in the blood).
- Bone Marrow Biopsy: Doctors may take a tiny sample of bone marrow to look at it under a microscope. They look for lots of cells and specific changes.
- Genetic Test: A blood test checks for the JAK2 gene mutation.
Doctors also check the level of erythropoietin (EPO). A very low EPO level is a strong clue that a person has PV.
Treatment and Management
Goals of Treatment
There is currently no cure for PV, but it can be managed well. The main goal is to prevent blood clots (thrombosis) by keeping the blood from getting too thick. Doctors try to keep the hematocrit level below 45%.
Blood Withdrawals
The most common treatment is called phlebotomy. This is very similar to donating blood. A nurse draws blood from a vein to reduce the number of red blood cells.
- At first, this might be done once a week.
- Once the blood levels are safe, it is done less often.
Medications
Doctors may prescribe medicines to help manage the condition.
Lifestyle Choices
Living a healthy life is important. Doctors recommend:
- Not smoking.
- Keeping a healthy weight.
- Staying active to help blood flow.
- Taking cool baths or showers if itching is a problem.
Outlook and Future
Living with PV
PV is a chronic condition, meaning it lasts a long time. However, with proper treatment, many people live a normal lifespan. Studies show that people can live with the condition for decades, especially if it is controlled well.
Possible Complications
The biggest risk with PV is blood clots. These can block blood vessels. Older patients (over 60) or those who have had clots before need to be extra careful.
In rare cases, PV can change into other conditions over time, such as myelofibrosis (scarring of the bone marrow) or acute myeloid leukemia. Regular check-ups with a hematologist (blood doctor) help monitor for these changes.
Who Gets Polycythemia Vera?
PV is not very common. It can happen at any age, but it is most often found in older adults.
- The average age for diagnosis is around 60 years old.
- It is rare in people under 40, affecting only about 10% of patients in that age group.
- It affects men slightly more often than women.
- It occurs in people of all ethnic backgrounds.
History and Notable Cases
Discovery
The disease was discovered by doctors William Osler and Louis Henri Vaquez. For a long time, it was known as Osler–Vaquez disease.
Famous People with PV
Some well-known people have lived with this condition:
- Juan Alderete, a musician.
- Will Self, a writer.
- Phyllis George, a sportscaster and former First Lady of Kentucky.
- Chet Lemon, a baseball player.
- Nell Rankin, an opera singer.
