Polycythaemia: Managing High Red Blood Cell Counts in the UK

Polycythaemia, also known as erythrocytosis, is a medical condition characterised by an abnormally high concentration of red blood cells in the blood. Red blood cells are responsible for carrying oxygen around the body; however, having too many can cause the blood to become thicker and less able to flow easily through small blood vessels.

According to NHS guidance, thick blood increases the risk of developing blood clots (thrombosis). There are two main types of the condition: Primary Polycythaemia (such as Polycythaemia Vera), which is a rare blood cancer where the bone marrow produces too many cells, and Secondary Polycythaemia, which is usually a response to other factors like chronic lung disease or smoking.

Many people with polycythaemia may not notice symptoms initially, and the condition is frequently discovered during routine blood tests. However, as the blood thickens, several physical signs may emerge:

• Headaches and Dizziness: Reduced blood flow to the brain can cause frequent lightheadedness.
• Visual Disturbances: Blurred or double vision, often temporary.
• Ruddy Complexion: A noticeable redness in the face, hands, or feet (plethora).
• Itching (Pruritus): Particularly after a warm bath or shower; this is a classic sign of polycythaemia vera.
• Fatigue: Feeling unusually tired or weak throughout the day.
• Painful extremities: A burning sensation in the hands or feet, known as erythromelalgia.

Secondary Polycythaemia

This is the most common form seen by GPs in the UK. It occurs when the body produces extra red blood cells to compensate for low oxygen levels. Common triggers include:

• Smoking: Carbon monoxide in cigarettes reduces oxygen transport, prompting the body to make more red cells.
• Chronic Obstructive Pulmonary Disease (COPD): Lung damage reduces oxygen intake.
• Sleep Apnoea: Brief periods of stopped breathing during sleep lower oxygen levels.
• High Altitude: Living in mountainous regions (less common in the UK, but relevant to travellers).
• Obesity: Which can impair normal breathing patterns.

Primary Polycythaemia (Polycythaemia Vera)

This is caused by a genetic mutation (usually the JAK2 mutation) in the bone marrow cells. It requires specialist management by a haematologist.

Diagnosis typically begins with a Full Blood Count (FBC). In the UK, clinicians look at the haematocrit (HCT) levels—the proportion of red cells in the blood—and the haemoglobin levels. NICE (National Institute for Health and Care Excellence) provides pathways for investigating raised haematocrit levels to differentiate between dehydration (relative polycythaemia) and true erythrocytosis.

If your levels are persistently high, your GP may order further tests, including oxygen saturation checks, erythropoietin (EPO) level tests, or a referral for a JAK2 genetic test to rule out primary bone marrow disorders.

Treatment depends entirely on the underlying cause. For secondary polycythaemia, the focus is on treating the root issue: quitting smoking, managing weight, or using a CPAP machine for sleep apnoea.

For those requiring direct intervention to thin the blood, the following may be recommended:

• Venesection (Phlebotomy): Similar to giving blood, a pint of blood is removed at regular intervals to lower the red cell count.
• Low-dose Aspirin: Often prescribed to reduce the risk of blood clots.
• Medication: In cases of Polycythaemia Vera, drugs like hydroxycarbamide may be used to slow down red cell production.
• Hydration: Maintaining good fluid intake is essential to prevent the blood from becoming too concentrated.

If you have received blood test results showing a high red blood cell count or a high haematocrit level, you may feel anxious about what this means. You can speak to a GP online to discuss these results in detail. An online doctor can help by:

• Explaining your Full Blood Count (FBC) results in plain English.
• Assessing your symptoms to determine if they align with polycythaemia.
• Providing advice on lifestyle changes, such as smoking cessation and weight management.
• Guiding you on whether you need an urgent referral to a haematologist.
• Issuing private referrals or suggesting specific follow-up tests.

Seeking an online GP consultation in the UK is a convenient way to get expert clinical advice without the wait for a traditional surgery appointment.