17810 High Red Blood Cell Count

Overview

Red blood cells carry oxygen from your lungs to the rest of your body. A high red blood cell count means you have more of these cells than usual. Doctors sometimes call it polycythaemia (say: pol-ee-sy-THEE-mee-uh). It is usually found on a routine blood test, often when you feel perfectly well. There are two broad types. In one type, the number of red cells is normal but the liquid part of your blood (the plasma) is low, usually because you are dehydrated. In the other type, your body really is making extra red cells — sometimes because it is reacting to low oxygen levels somewhere in the body, and sometimes because of a rare problem in the bone marrow itself. Having a high count is not a diagnosis on its own. It is a signal that your doctor needs to look a little closer to understand why.

Mildly raised red cell counts are fairly common, especially in people who smoke, live at high altitude, or were a bit dehydrated when the blood sample was taken. True polycythaemia vera, the bone marrow condition, is rare — it affects only a small number of people each year.

It can affect anyone, but it is more often seen in men, in people over 50, in smokers, in people with long-term lung or heart conditions or sleep apnoea, in people living at high altitude, and in people who take certain hormones or water tablets. It is uncommon in children, and when it does happen, the cause is usually another health condition.

Symptoms

Common symptoms

• Often no symptoms at all — the high count is found by chance on a blood test
• Headaches and dizziness
• Tiredness or weakness, even after a full night's sleep
• A red or flushed face, and skin that feels warm
• Blurred vision or seeing spots
• Itching, especially after a warm bath or shower — this is a classic sign and worth mentioning to your doctor
• Sweating more than usual, sometimes at night
• Ringing or buzzing in the ears
• Easy bruising, nosebleeds, or bleeding gums
• A full or heavy feeling in the upper left side of the belly (this can be an enlarged spleen)
• Sudden sharp pain and swelling in a joint, often the big toe (gout)
• Trouble concentrating or feeling 'fuzzy'

Symptoms in children

• A high red cell count is uncommon in children and is usually linked to another cause, such as a heart or lung problem or living at high altitude
• Newborn babies may look unusually red or, in some cases, slightly blue-tinged around the lips
• Babies may feed poorly, be extra sleepy, or be more irritable than usual
• Older children may complain of headaches, tiredness, or blurred vision
• Children with a high count are usually checked by a children's specialist (paediatrician) to look for the cause

Symptoms in older adults

• Symptoms like tiredness and dizziness are sometimes put down to getting older, so the blood test result is what raises the question
• Confusion or poor concentration can be an early sign in older people
• There is a higher chance of blood clots, so symptoms like leg swelling or breathlessness need prompt attention
• Itching after a warm shower is easily missed but is worth reporting
• Some medicines used for other conditions can affect the red cell count, so bring a full medicine list to your appointment

Causes

Main causes

• Dehydration — less liquid in the blood makes the red cells look more concentrated than they really are
• Smoking, which reduces the oxygen in your blood and makes your body produce more red cells
• Long-term low oxygen levels from lung conditions, heart problems, or sleep apnoea (a condition where breathing briefly stops and starts during sleep)
• Living at high altitude, where the air holds less oxygen
• Kidney problems, because the kidneys make a hormone that tells the bone marrow to produce red cells
• Some hormone treatments and some water tablets
• Rarely, polycythaemia vera — a condition where the bone marrow itself makes too many red cells
• Very rarely, certain tumours or inherited conditions that affect how the body senses oxygen

Risk factors

• Smoking
• Living at high altitude
• Long-term lung or heart disease
• Sleep apnoea, especially if you snore heavily and feel unrefreshed in the morning
• Being male and over 50
• A family history of polycythaemia vera
• Taking certain hormone treatments or water tablets
• Being very overweight
• Long periods without drinking enough fluids

When to see a doctor

See a doctor urgently if:

• Swelling, pain, or redness in one leg
• Sudden changes in your vision
• Chest pain or breathlessness
• Bleeding that keeps coming back
• Confusion or fainting
• A severe headache that feels different from usual

Book a routine appointment if:

• A blood test has shown a high red cell count or high haemoglobin (the oxygen-carrying part of the red cell)
• You have itching after a warm bath or shower
• You feel unusually tired, dizzy, or foggy for more than a few weeks
• Your skin looks redder than usual, or your face is often flushed
• You have a family member with a blood condition
• You are planning a trip to high altitude and have a known lung or heart condition

Diagnosis

Your doctor will start by repeating the blood test, usually when you are well hydrated, because a single high result can be misleading. They will ask about your symptoms, whether you smoke, where you live, your sleep and snoring, and any medicines you take. If the count is still high, they will arrange tests to work out whether it is a 'true' rise and, if so, what is causing it. Most people only need a few of these tests.

Tests that may be done

• A full blood count — measures red cells, haemoglobin, white cells, and platelets
• A repeat blood test after drinking normally, to rule out dehydration
• A blood film — a drop of blood looked at under a microscope
• A hormone level test (erythropoietin), which helps show whether the bone marrow is being overstimulated
• Oxygen level checks, such as a small clip on your finger or a blood sample from the wrist
• A sleep study if sleep apnoea is suspected
• An ultrasound scan of the tummy to look at the kidneys, liver, and spleen
• A genetic blood test to look for the change linked to polycythaemia vera
• Rarely, a bone marrow sample taken with a small needle under local anaesthetic

What to expect at your appointment

It can take a few appointments and a few weeks to get the full picture. Waiting for results is often the hardest part, so it can help to write down your questions and bring someone with you. Try to remember that many people turn out to have a simple explanation, such as smoking, dehydration, or a breathing problem during sleep, and that these can be treated or improved.

Treatment

Treatment depends entirely on the cause and on how high the count is. If the rise is mild and down to dehydration or smoking, the answer may simply be drinking more and stopping smoking. If another condition is behind it — such as sleep apnoea or a lung problem — treating that usually brings the count down. If a bone marrow condition is found, treatment aims to bring the red cells closer to normal and lower the risk of blood clots.

Self-care at home

• Drink water regularly through the day, and more in hot weather or when exercising
• If you smoke, ask your doctor or pharmacist about the support available to help you stop — this is one of the most effective steps
• Keep moving and avoid sitting still for long stretches, especially on long journeys
• Don't start iron supplements unless your doctor has advised it, as extra iron can raise red cell production
• Keep a note of your symptoms so you can tell your doctor what has changed
• Attend your follow-up blood tests — they are how your team keeps you safe
• Wear a medical alert card or bracelet if your specialist advises it

Medical treatments

Your team may suggest regularly removing a small amount of blood, a bit like giving blood, to bring the red cell level down — this is called venesection. Some people are offered medicines that gently slow the bone marrow's production of red cells. A small daily dose of a blood-thinning medicine is sometimes suggested to lower the chance of clots. If low oxygen from sleep apnoea or a lung problem is the cause, treatment for that — such as breathing support at night or oxygen therapy — can reduce the count on its own. Your doctor will explain the options that fit your situation and the risks and benefits of each.

When is surgery considered?

Surgery is rarely part of treatment for a high red cell count. Occasionally, if a tumour or other growth is found to be causing the extra red cells, an operation may be needed to treat that underlying problem.

Living with this condition

Most people with a high red cell count live a normal life. You may have regular blood tests to keep an eye on your levels, and it helps to know the warning signs of a clot — sudden weakness on one side, chest pain, or a painful swollen leg — so you can act quickly. Tell any doctor, dentist, or nurse you see about your condition, and mention it before long flights or travel to high places.

Lifestyle tips

• Stop smoking if you can — this is the single biggest change that helps
• Stay active most days, and stand up and stretch on long journeys
• Keep to a healthy weight, which helps sleep apnoea and blood pressure
• Get sleep apnoea treated if you have it
• Keep alcohol within recommended limits
• Manage other heart and stroke risks, such as blood pressure, with your GP

Diet and exercise

There is no special diet for a high red cell count. A balanced diet with plenty of vegetables, fruit, and fibre, and plenty of fluid, is a good foundation. Drinking water before, during, and after exercise matters more than usual for you. Moderate exercise — walking, swimming, cycling — is encouraged and helps your circulation. If you exercise hard or in hot weather, take extra fluids and watch for dizziness. Check with your doctor before travelling to high altitude or doing very strenuous activity in the heat.

Mental health and emotional wellbeing

Being told your blood count is abnormal can be worrying, and waiting for results can be stressful. Some people find themselves checking every symptom and fearing clots. That reaction is completely understandable. Talking it through with your GP, a specialist nurse, or a counsellor can help. If you have a family or whānau you trust, let them in. If low mood or anxiety is affecting your sleep, appetite, or daily life, please reach out for support — you do not have to manage it alone.

Prevention

Some causes can be prevented or reduced, and others cannot. You cannot control your age, sex, or family history, and polycythaemia vera is not caused by anything you did. But not smoking, staying well hydrated, keeping active, treating sleep apnoea, and managing long-term lung and heart conditions all lower the chance of a raised count — and they are good for your health in many other ways too.

Screening programmes

There is no routine screening programme for a high red cell count. It is usually picked up on a blood test done for another reason. If you have a close relative with polycythaemia vera, tell your doctor, as they may want to check your blood count from time to time.

Complications

If left untreated

• Blood clots, which can form in the leg, lung, brain, or heart — this is the main reason the count is taken seriously
• Bleeding problems, because the extra cells can affect how your blood clots
• An enlarged spleen, which can cause a full or uncomfortable feeling in the upper belly
• Gout — sudden painful, swollen joints
• Intense itching after warm water, which can disturb sleep
• Stomach ulcers
• In polycythaemia vera, over many years the bone marrow can change and need closer monitoring

Long-term outlook

The outlook is generally good. Most people with a mildly raised count find the cause is something treatable, and the count settles once that is addressed. For people with polycythaemia vera, the condition is long-term but can usually be kept under good control with monitoring and treatment, and most people live full, active lives. Keeping your appointments, taking the steps you can, and knowing the warning signs are the most powerful things you can do.

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