Erythrocytosis

Overview

Erythrocytosis means you have more red blood cells than usual, or your red blood cells contain more haemoglobin (the red protein that carries oxygen) than normal. Red blood cells are made in your bone marrow and their job is to carry oxygen from your lungs to the rest of your body. When there are too many of them, your blood becomes thicker and stickier than it should be, which can make it harder for blood to flow smoothly. Erythrocytosis is not a disease on its own — it is more like a signal or a clue. Something else is usually behind it, such as smoking, a lung problem, sleep apnoea (a condition where breathing stops and starts during sleep), or, less often, a problem in the bone marrow itself. Many people find out they have it from a routine blood test and feel completely well.

A raised red cell count is a fairly common finding on blood tests. Most cases are mild and are caused by something straightforward, like smoking, being dehydrated on the day of the test, or living at high altitude. The rarer bone marrow cause, polycythaemia vera, is uncommon — roughly a few people in every 100,000 are diagnosed each year.

It can affect anyone at any age. It is more often noticed in men and in people over 60, and in people who smoke, have long-term lung or heart problems, are very overweight, use anabolic steroids (medicines sometimes used to build muscle), or live at high altitude. Children can get it too, usually because of an underlying heart or lung condition or, very rarely, an inherited blood condition.

Symptoms

Common symptoms

• Often no symptoms at all — it may only show up on a blood test
• Headaches or a heavy, throbbing feeling in the head
• Feeling tired, weak, or light-headed
• Dizziness or ringing in the ears
• Blurred vision or 'floaters' in your sight
• A flushed, red face or generally redder skin than usual
• Sweating more than usual, especially at night
• Itchy skin, which can be worse after a warm bath or shower
• Unusual tiredness or breathlessness with mild effort
• Aching or burning in the hands and feet
• Bruising or bleeding more easily than usual

Symptoms in children

• Often found by chance on a blood test done for another reason
• Headaches, irritability, or trouble concentrating
• Looking flushed or having very red cheeks and lips
• Bluish lips or fingertips if the cause is a heart or lung problem
• Poor feeding or slow weight gain in babies
• Tiredness or getting out of breath more quickly than other children when playing

Symptoms in older adults

• Symptoms may be put down to 'just getting older', such as tiredness, dizziness, or poor concentration
• Headaches or visual changes that come and go
• Symptoms of the underlying cause, such as loud snoring or daytime sleepiness from sleep apnoea
• Itchy skin, especially after a hot shower or bath
• Gout (sudden painful, swollen joints, often the big toe)
• A higher risk of clots, so any new chest pain or weakness needs urgent attention

Causes

Main causes

• Not enough oxygen reaching your tissues, so your body makes extra red cells to compensate — for example from smoking, long-term lung disease (such as COPD), sleep apnoea, some heart conditions, or living at high altitude
• The 'relative' type: your red cells are normal in number but your blood plasma (the watery part) is low, usually from dehydration, vomiting, diarrhoea, or certain water tablets
• Bone marrow problems, including polycythaemia vera — a condition where the bone marrow makes too many blood cells (a type of blood cancer)
• Kidney problems such as cysts or, rarely, tumours, because the kidneys make the hormone that tells the bone marrow to produce red cells
• Rarely, liver tumours or other growths that produce the same hormone
• Medicines or hormones, including anabolic steroids and some testosterone treatments
• Inherited conditions that change how haemoglobin holds oxygen, or how the body senses oxygen levels
• Blood doping (using extra blood or hormones to boost performance in sport)

Risk factors

• Smoking
• Long-term lung disease, such as COPD or pulmonary fibrosis
• Sleep apnoea or long-term snoring with daytime sleepiness
• Living at high altitude
• Being overweight or having obesity
• Dehydration
• Kidney disease, kidney cysts, or having had a kidney transplant
• Use of anabolic steroids or testosterone treatments
• Being male, and being over 60
• A family history of polycythaemia vera or of a rare inherited red cell condition
• Some heart conditions present from birth

When to see a doctor

See a doctor urgently if:

• Chest pain, sudden breathlessness, or signs of a stroke — call your local emergency number straight away
• A sudden severe headache, confusion, or a seizure
• Heavy bleeding, or bleeding that will not stop
• A hot, red, swollen joint, or pain in the upper left of your abdomen
• A rapid change in your vision

Book a routine appointment if:

• A blood test has shown a raised haemoglobin or haematocrit level
• You have had headaches, dizziness, flushing, or itchy skin that keep coming back
• You snore heavily, wake unrefreshed, or feel very sleepy during the day
• A close family member has been diagnosed with polycythaemia vera
• You are taking testosterone, anabolic steroids, or other hormone treatments and are worried

Diagnosis

Your doctor will start by asking about your health, medicines, smoking, sleep, and where you live, and will examine you. They will usually repeat the blood test — often after making sure you are well hydrated — to confirm the reading is real. Further tests then look for the underlying cause. If no simple cause turns up, or if your levels are clearly high, you may be referred to a haematologist (a doctor who specialises in blood).

Tests that may be done

• A full blood count — measures haemoglobin, haematocrit, and all the different blood cell types
• A blood test to check your level of erythropoietin (EPO), the hormone that tells your bone marrow to make red cells
• A genetic test on your blood for a change called JAK2, which is common in polycythaemia vera
• Tests for iron levels, vitamin B12, and folate
• A blood oxygen reading (a small clip on your finger) and possibly a test of your breathing
• A sleep study if sleep apnoea is suspected
• An ultrasound scan of your kidneys and abdomen
• A chest X-ray if a lung problem is suspected
• Rarely, a bone marrow biopsy — a small sample of bone marrow taken from your hip under local anaesthetic

What to expect at your appointment

Most of the tests are simple blood tests, and you may need to visit your GP or a clinic a few times over several weeks. Results can take a little while, especially the genetic test. It helps to write down your questions as you go, and to take someone with you if you can. Try not to worry while you wait — your doctor is checking for common, treatable causes first, and most people do not need every test on this list.

Treatment

Treatment depends entirely on what is causing the erythrocytosis. If the cause is something you can change, such as smoking or dehydration, fixing that often brings your red cell count back to normal. If an underlying condition is found — such as sleep apnoea, a heart problem, or a kidney problem — treating it usually settles the red cells too. If the cause is polycythaemia vera or your levels are high enough to raise the risk of clots, a specialist will recommend treatment to bring your count down and keep it in a safer range.

Self-care at home

• Drink plenty of water through the day, and more in hot weather or when exercising
• Stop smoking — this is one of the single biggest things you can do, and ask your doctor or pharmacist for support
• Keep moving: regular gentle activity helps your circulation
• Avoid long periods of sitting still, especially on long journeys — stretch your legs regularly
• Tell your doctor or pharmacist about every medicine you take, including testosterone, steroids, and supplements bought online
• Avoid altitude holidays without checking with your doctor first if your levels are high
• Go for your follow-up blood tests even when you feel well

Medical treatments

Doctors may use one or more approaches. The first is treating the underlying cause — for example, support to stop smoking, treatment for sleep apnoea, or treatment for a heart, lung, or kidney problem. The second is lowering the number of red blood cells directly. This is often done by removing some blood at regular intervals (sometimes called blood letting or venesection) — a bit like giving blood — which brings the count down safely. Some people are given medicines that reduce how many blood cells the bone marrow makes, or a low dose of a medicine that makes the blood less likely to clot. Your specialist will explain which option suits you, based on your age, your levels, your symptoms, and your other health conditions.

When is surgery considered?

Surgery is not used to treat erythrocytosis itself. Occasionally, surgery may be needed for a condition found during the tests — for example, removing a kidney growth that is producing the hormone driving the red cell count. Your specialist team would discuss this with you in detail if it applied to you.

Living with this condition

For most people, living with erythrocytosis means a few adjustments and regular check-ups rather than big changes. You may have blood tests every few months and, if your levels are high, appointments to remove some blood. It helps to know your own warning signs — such as a new headache, changes in vision, or unusual breathlessness — so you can act on them quickly. Keep a simple record of your appointments and test results if that helps you feel in control.

Lifestyle tips

• Stay well hydrated, especially before blood tests, in hot weather, and during exercise
• Get support to stop smoking — this can make a real difference to your red cell count
• Keep to a healthy weight and be active most days
• If you snore heavily or feel sleepy in the day, ask about a sleep apnoea assessment
• Avoid taking testosterone or anabolic steroids without medical advice
• Take care of your skin if it is itchy — lukewarm rather than hot showers, and a gentle moisturiser
• Get recommended vaccinations and routine health checks, since you may be at slightly higher risk from infections and heart strain

Diet and exercise

There is no special diet for erythrocytosis, but a balanced diet and plenty of fluids help your circulation and general health. Aim for regular, moderate activity — walking, swimming, cycling, or whatever you enjoy — which helps keep blood flowing and supports your heart and lungs. Avoid getting badly dehydrated during exercise, and take breaks on very hot days. If you have another condition such as heart or lung disease, ask your doctor what level of activity is right for you before starting something new or intense.

Mental health and emotional wellbeing

Being told you have a raised blood count, and waiting for test results, can be worrying — especially if the word 'blood cancer' comes up. It is very normal to feel anxious, and many people find their mind goes to the worst case while they wait. Talking about how you feel helps: with your doctor, a trusted friend or family member, or a counsellor. If low mood or worry is affecting your sleep, appetite, or daily life for more than a couple of weeks, please speak to your doctor. If you ever feel overwhelmed or have thoughts of harming yourself, contact your local emergency number or a crisis support line in your country straight away — you deserve support and you do not have to cope alone.

Prevention

Some types can be prevented and some cannot. The kinds caused by smoking, dehydration, obesity, or untreated sleep apnoea can often be avoided or reversed by tackling those issues. The kinds caused by an inherited condition, a bone marrow disorder, or a kidney problem cannot be prevented, but they can be picked up early and managed well.

Vaccines

There is no vaccine for erythrocytosis. It is still worth keeping up to date with the vaccinations your doctor recommends for your age and health, as this helps protect you from infections that can make any underlying heart or lung condition harder to cope with.

Screening programmes

There is no national screening programme for erythrocytosis. A raised red cell count is usually picked up on a routine full blood count done for another reason. If you have a strong family history of polycythaemia vera or a rare inherited red cell condition, speak to your doctor about whether any checks are appropriate for you.

Complications

If left untreated

• A higher chance of blood clots, which can cause a stroke, heart attack, or a clot in the leg or lung
• Thicker blood that flows less easily, which can cause headaches, dizziness, and tiredness
• Gout — a painful, swollen joint caused by a build-up of uric acid
• An enlarged spleen, which can cause discomfort or fullness in the upper left of the abdomen
• Persistent itchy skin, especially after a warm shower or bath
• In people with polycythaemia vera, a small risk over many years of the bone marrow changing and, rarely, developing into a more serious blood condition
• Bruising or bleeding more easily than usual

Long-term outlook

The outlook is generally good, and for most people erythrocytosis is manageable rather than life-limiting. If the cause is something like smoking, dehydration, or sleep apnoea, correcting it often brings levels back to normal. If you have polycythaemia vera, it is a long-term condition that needs monitoring, but with regular follow-up and treatment most people live full and active lives for many years. Your medical team will work with you to keep your levels in a safer range and to watch for any changes early.

Find support

External links open third-party websites. Ruqelo Health is not responsible for external content. Listing an organisation does not imply endorsement.