Blood disorders: types, symptoms and how they are diagnosed and treated

Blood is made of red cells that carry oxygen, white cells that fight infection, platelets and clotting proteins that stop bleeding, and plasma. A blood disorder is any condition that disturbs one of these. This guide gives a map of the main groups and points you to the detailed guide for each. It covers anaemias, inherited haemoglobin conditions, bleeding disorders and blood cancers, using NHS and charity information.

The groups differ greatly in how serious they are. Iron deficiency anaemia is common and treatable with tablets, according to the NHS, while some inherited conditions need lifelong specialist care and some blood cancers need treatment from a haematology team. A haematologist is the doctor who specialises in diseases of the blood.

Symptoms depend on which blood component is affected. The NHS describes the following for the main conditions.

The NHS describes iron deficiency anaemia as caused by lack of iron, often because of blood loss or pregnancy, and treated with iron tablets and iron-rich foods. It says it is the most common type of anaemia. Heavy periods and pregnancy are very common causes, and bleeding in the stomach and intestines from NSAIDs, stomach ulcers, bowel inflammation, piles or, less commonly, cancers of the bowel or stomach is another. Your GP will usually do a full blood count and, if the reason is unclear, may arrange further tests such as a FIT test for blood in poo. Iron tablets are usually taken for about 6 months, with repeat blood tests to check iron levels return to normal.

The NHS says vitamin B12 or folate deficiency anaemia occurs when a lack of these vitamins causes the body to produce abnormally large red blood cells that cannot function properly. The most common cause of B12 deficiency in the UK is pernicious anaemia, where the immune system attacks cells in the stomach, but low dietary intake (for example a vegan diet without supplements) and some medicines, including anticonvulsants and proton pump inhibitors, can also lower levels. It says deficiency affects around 1 in 10 people aged 75 or over. Treatment is B12 injections or tablets, and folic acid tablets, usually for about 4 months. The NHS stresses early treatment because some problems caused by the condition can be irreversible.

The NHS describes sickle cell disease as an inherited condition that affects red blood cells and can cause pain, swelling and tiredness. It is usually lifelong, but treatments can help. Symptoms can start from around 6 months old and typically come and go. A sickle cell crisis is sudden, severe pain or other symptoms such as blurred vision, a high temperature or a painful erection that does not go away, lasting hours, days or weeks. It can be triggered by dehydration, a sudden change in temperature and stress. Treatments include painkillers, penicillin or erythromycin to prevent infection (particularly in children), vaccinations, hydroxycarbamide to reduce pain crises, blood transfusions and red cell exchange. Stem cell or bone marrow transplants and gene therapy are sometimes used to cure sickle cell disease.

Thalassaemia is a group of inherited conditions affecting haemoglobin, according to the NHS. Beta thalassaemia major is the most severe type. A child can be born with thalassaemia only if they inherit faulty genes from both parents, and the NHS says that where both parents carry beta thalassaemia major there is a 1 in 4 chance of each child being born with the condition. Treatments for serious types are regular blood transfusions, sometimes around once a month, and chelation therapy to remove excess iron. The only possible cure is a stem cell or bone marrow transplant, which is not done often because of the risks. With current treatments the NHS says people are likely to live into their 50s, 60s and beyond.

The NHS says haemophilia is a rare condition that affects the way your blood clots, caused by a lack of a clotting factor protein. Haemophilia A is a lack of factor 8 and haemophilia B a lack of factor 9. Most people are born with it, symptoms usually begin in early childhood, and men with the altered gene have symptoms; women who carry it can have symptoms but less commonly and less severe. Treatment is usually injections of clotting factor, and the NHS says people with severe haemophilia usually need injections up to 3 times a week to prevent bleeding, which they can often do at home, while those with mild or moderate haemophilia usually only need treatment to stop bleeding once it starts. Other medicines include emicizumab, desmopressin and tranexamic acid.

The NHS describes von Willebrand disease as an inherited condition where the blood does not clot properly, so you bleed more easily. There is no cure but most people have mild symptoms that can be managed. It can be hard to diagnose because symptoms are often mild, and several blood tests over days or weeks are needed. Types 1 and 2 are most common and usually mild; type 3 is rare and more severe. The NHS advises people with von Willebrand disease not to take ibuprofen, other NSAIDs or aspirin, and to speak to their specialist team before surgery, dental treatment or pregnancy.

Blood cancers affect the cells that make up blood and the lymphatic system. Cancer Research UK says non-Hodgkin lymphoma is a type of blood cancer affecting white blood cells called lymphocytes, with around 13,700 people diagnosed each year in the UK. The NHS says its most common symptom is a painless lump in the neck, armpit or groin. Chronic myeloid leukaemia, according to Cancer Research UK, develops from myeloid stem cells, usually very slowly, with around 900 people diagnosed each year in the UK, and is mainly treated with tablets called tyrosine kinase inhibitors. Chronic myelomonocytic leukaemia (CMML), per Leukaemia Care, is a rare blood cancer affecting monocytes, with around 650 people diagnosed a year in the UK.

Treatment of blood cancers is led by haematology teams. Depending on the type it can include watch and wait, chemotherapy, targeted medicines, immunotherapy, radiotherapy and stem cell transplant. See the dedicated guides for B-cell lymphoma, chronic myeloid leukaemia and CMML for more detail.

The NHS says a blood test can be done to check your general health, find out if symptoms are caused by certain conditions, or see how well a condition is being managed. The full blood count (FBC) measures the number of blood cells to check for blood conditions such as iron deficiency anaemia. The test usually takes about 10 minutes, with blood taken from the inside of the elbow, and the NHS says you may get results after a few days.

Specific tests then follow depending on the suspected condition: clotting factor levels for haemophilia, several blood tests for von Willebrand disease, genetic and carrier testing for sickle cell and thalassaemia, and a lymph node or bone marrow biopsy for suspected lymphoma or leukaemia. The NHS says sickle cell disease is usually found through pregnancy and newborn screening programmes, and that thalassaemia screening in pregnancy is offered to all pregnant women in England.

Several blood disorders are relevant to pregnancy. The NHS says iron deficiency anaemia is commonly caused by pregnancy, most often through lack of iron in the diet, and that untreated it can increase the risk of complications before and after birth. If you are pregnant you will usually be offered screening for sickle cell disease by your midwife before 10 weeks, a blood test that checks whether you carry the genes that could be passed to your baby, though you do not have to have it.

For haemophilia the NHS says to see a GP if you are pregnant or planning a pregnancy and someone in your or your partner's family has it, and a GP may refer you to a genetic counsellor to discuss tests before, during and after pregnancy. For von Willebrand disease, the NHS says to speak to your specialist team if you are pregnant or trying to get pregnant, because you will need monitoring during pregnancy and the birth.

Many inherited blood conditions show up in babies and children. The NHS says most babies are checked for sickle cell disease in the newborn blood spot (heel prick) test, and that sickle cell symptoms can start from 6 months old. It says most people with thalassaemia have health problems from a few months after birth, and that symptoms of haemophilia usually begin in early childhood. For sickle cell disease, antibiotics such as penicillin are given to help prevent serious infections, particularly in children, along with vaccinations. The NHS warns that iron tablets must be kept out of the reach of children, because an overdose of iron in a young child can be fatal.

The NHS says to call 999 if you think you are having a sickle cell crisis with severe pain, breathing difficulties or being sick, if you have sickle cell disease and a high temperature, or if you have an erection that is painful or does not go away. For von Willebrand disease it says to go to A&E if you have a nosebleed lasting longer than 10 to 15 minutes, or an injury or cut and cannot stop the bleeding, and to get urgent help from a GP or NHS 111 if you have blood in your pee or black or dark red poo.

See a GP for a persistent painless lump, as Cancer Research UK advises seeing your GP about a swollen lymph node that does not go away after 3 to 4 weeks, for persistent tiredness, breathlessness and pale skin, for repeated infections, and for unusual bruising or bleeding.

In the NHS, most blood disorders are first picked up by a GP blood test, with referral to a haematology service for specialist diagnosis and ongoing care. People with haemophilia are treated through a haemophilia centre, and people with sickle cell disease or thalassaemia by specialist haemoglobinopathy teams. Some people also use private haematology consultations for faster access to tests or a second opinion; the diagnostic tests and treatment options are the same, and results should be shared with your GP and NHS specialist team.