Is Polycythemia Dangerous? Why Your Blood Is Thickening & Medically Approved Next Steps

Polycythemia is a medical condition where your body makes too many red blood cells. Because red blood cells carry oxygen, that may sound like a good thing. But when levels become too high, your blood can become thicker than normal. Thickened blood does not flow as easily, and that can increase the risk of serious health problems.

So, is polycythemia dangerous?
The honest answer is: it can be, especially if it goes untreated. The good news is that with proper medical care, many people live long and stable lives.

Let's break down what polycythemia is, why it happens, what risks it carries, and what steps doctors recommend.

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What Is Polycythemia?

Polycythemia means an increased concentration of red blood cells in the bloodstream. This is usually detected through a blood test showing elevated:

• Hemoglobin
• Hematocrit
• Red blood cell count

There are two main types of polycythemia:

1. Primary Polycythemia (Polycythemia Vera)

• A rare blood cancer.
• Caused by a genetic mutation (most commonly in the JAK2 gene).
• The bone marrow makes too many red blood cells without needing a signal from the body.

2. Secondary Polycythemia

• Caused by another condition.
• Often triggered by chronic low oxygen levels.
• Common causes include:
  • Smoking
  • Sleep apnea
  • Chronic lung disease (like COPD)
  • Living at high altitude
  • Certain tumors that increase erythropoietin (EPO)

In short:
Primary polycythemia starts in the bone marrow. Secondary polycythemia is the body reacting to something else.

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Why Is Thick Blood Dangerous?

When red blood cells increase too much, blood becomes thicker (more viscous). Thick blood moves more slowly and can form clots more easily.

This raises the risk of:

• Stroke
• Heart attack
• Deep vein thrombosis (DVT)
• Pulmonary embolism
• Heart strain
• High blood pressure

In polycythemia vera, there is also a small risk of progression to:

• Myelofibrosis (bone marrow scarring)
• Acute leukemia (rare but serious)

That said, not everyone with polycythemia experiences complications. Risk depends on:

• Age
• Cardiovascular health
• Smoking status
• Clotting history
• How well the condition is managed

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Symptoms of Polycythemia

Some people have no symptoms at first. Others may notice:

• Headaches
• Dizziness
• Blurred vision
• Fatigue
• Itching after a warm shower (common in polycythemia vera)
• Red or flushed skin
• Shortness of breath
• Numbness or tingling
• Easy bruising

These symptoms happen because thick blood does not circulate as smoothly, reducing oxygen delivery and increasing pressure in blood vessels.

Interestingly, some symptoms like fatigue and shortness of breath can overlap with the opposite condition—low red blood cell count. If you're experiencing unexplained tiredness or weakness and want to explore whether Anemia might be contributing to your symptoms, a free AI-powered assessment can help you better understand what to discuss with your doctor.

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How Serious Is Polycythemia?

Mild Cases

In some people—especially with secondary polycythemia caused by altitude or mild oxygen deprivation—the condition may be manageable and reversible.

Moderate to Severe Cases

Polycythemia vera is considered a chronic blood cancer. Without treatment, it can significantly increase the risk of life-threatening clots.

However:

• Early diagnosis
• Regular monitoring
• Proper treatment

…dramatically lower these risks.

Many patients live decades with controlled disease under specialist care.

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How Is Polycythemia Diagnosed?

Doctors use:

• Complete blood count (CBC)
• Hematocrit and hemoglobin levels
• Erythropoietin (EPO) level
• JAK2 mutation testing
• Bone marrow biopsy (in some cases)

Diagnosis is important because treatment differs between primary and secondary forms.

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Medically Approved Next Steps

If your blood work shows elevated red blood cells, here's what typically happens next.

1. Confirm the Diagnosis

Your doctor will:

• Repeat blood tests
• Check oxygen levels
• Test for genetic mutations
• Evaluate underlying conditions

Do not assume polycythemia based on one lab result. Dehydration alone can temporarily increase hematocrit.

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2. Treat the Underlying Cause (Secondary Polycythemia)

If the cause is identified, treatment focuses on correcting it:

• Quit smoking
• Treat sleep apnea with CPAP
• Manage lung or heart disease
• Adjust medications if needed

When oxygen levels improve, red blood cell production often decreases.

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3. Therapeutic Phlebotomy

This is one of the most common treatments for polycythemia vera.

• Blood is removed (similar to donating blood).
• Reduces hematocrit.
• Lowers clot risk.

Many patients need this regularly.

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4. Low-Dose Aspirin

Doctors often prescribe low-dose aspirin to reduce clot risk, unless contraindicated.

Do not start aspirin without medical advice, especially if you have bleeding risks.

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5. Medications

For higher-risk patients (such as those over 60 or with clot history), medications may be prescribed:

• Hydroxyurea
• Interferon
• JAK inhibitors (such as ruxolitinib)

These medications help suppress excess red blood cell production.

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6. Lifestyle Changes

While lifestyle alone cannot cure polycythemia vera, it reduces complications:

• Stay hydrated
• Exercise regularly (moderate activity improves circulation)
• Maintain a healthy weight
• Control blood pressure and cholesterol
• Avoid smoking

Hydration is especially important because dehydration can further thicken blood.

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When Is Polycythemia an Emergency?

Seek urgent medical care if you experience:

• Sudden chest pain
• Shortness of breath
• Sudden weakness on one side
• Trouble speaking
• Severe headache
• Swelling or pain in one leg

These could signal a blood clot, stroke, or heart attack.

Do not wait. These are medical emergencies.

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Can Polycythemia Be Cured?

• Secondary polycythemia may resolve if the underlying cause is treated.
• Polycythemia vera is not currently curable, but it is manageable.

With regular monitoring and treatment, many patients maintain good quality of life.

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Should You Be Worried?

Concern is reasonable. Panic is not helpful.

Polycythemia is serious because of clot risk. But it is also:

• Detectable
• Treatable
• Manageable

The biggest danger comes from ignoring symptoms or avoiding follow-up care.

If you've been told your blood is thick or your hematocrit is high, your next best step is simple:

Schedule an appointment with your doctor or a hematologist.

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The Bottom Line

Polycythemia can be dangerous, particularly if untreated. Thickened blood increases the risk of clotting, stroke, and heart attack. In rare cases, polycythemia vera may progress to more serious blood disorders.

But here's what matters most:

• Early detection saves lives.
• Proper treatment dramatically reduces risk.
• Most patients do well with consistent care.

If you have symptoms, abnormal blood tests, or risk factors, speak to a doctor promptly. Anything involving blood clot risk can become life-threatening if ignored.

Your health decisions should always be made with a qualified medical professional who can assess your full medical history and risk profile.

If something feels wrong, don't guess.
Speak to a doctor.