Sickle cell disease affects the red blood cells and is the name for a group of inherited conditions. Sickle cell anaemia is the most serious type.
“Peculiar elongated and sickle-shaped” is how sickle cells were first described in 1904 by intern Ernest Edward Irons when examining the blood of Walter Clement Noel, a 20-year-old first-year dental student from a wealthy Black family in Grenada. Noel had been admitted to the Chicago Presbyterian Hospital suffering from anemia and was readmitted several times over the next three years before completing his studies and returning to Grenada to successfully practice dentistry. He died of pneumonia in 1916.
Iron’s supervising physician, James B. Herrick, wrote a paper published in 1910 in the Archives of Internal Medicine documenting the first known case of sickle cell disease in the United States. (Source: https://www.sicklecellnewjersey.org/)
Sickle cell disease mainly affects people of African, Caribbean, Middle Eastern, Eastern Mediterranean and Asian origin. In the UK, it’s particularly common in people with an African or Caribbean family background.
People with sickle cell disease produce unusually shaped red blood cells that can cause problems because they don’t live as long as healthy blood cells and they can become stuck in blood vessels.
Sickle cell disease is a serious and lifelong condition, although long-term treatment can help manage many of the problems associated with it.
Sickle cell disease can cause a wide range of symptoms.
These can start from a few months of age, although many children have few or no symptoms if treatment is started early on.
Some of the main symptoms are outlined below, although not everyone with the condition will experience all of these.
Episodes of pain – known as sickle cell crises – are one of the most common and distressing symptoms of sickle cell disease. They occur when blood vessels to part of the body become blocked.
The pain can be severe and lasts for up to seven days on average.
A sickle cell crisis often affects a particular part of the body, such as the:
- hands or feet (particularly in young children)
- ribs and breastbone
- legs and arms
How often someone with sickle cell disease gets episodes of pain varies a lot. Some people may have one every few weeks, while others may have less than one a year. The average is one bad episode a year.
It’s not always clear what triggers bad pain, but sometimes they can be caused by the weather (such as wind, rain or cold), dehydration, stress or strenuous exercise.
People with sickle cell disease are more vulnerable to infections, particularly when they’re young.
This is because the condition can mean the body isn’t very good at dealing with bacteria and viruses.
Vaccinations and daily doses of antibiotics can help reduce the risk of many infections.
Nearly all people with sickle cell disease have anaemia, where the haemoglobin in the blood is low. Haemoglobin is the substance found in red blood cells that’s used to transport oxygen around the body.
This doesn’t usually cause many symptoms, but sometimes it can get worse if you become infected with the virus that causes slapped cheek syndrome (parvovirus).
This can lead to a sudden drop in the number of red blood cells and may cause additional symptoms such as headaches, a rapid heartbeat, dizziness and fainting. It’s usually treated with a blood transfusion.
In young children, swelling of the spleen can also cause sudden anaemia that requires a blood transfusion.
Sickle cell disease can also sometimes cause a wide range of other problems, including:
- delayed growth during childhood and delayed puberty
- gallstones (small stones in the gallbladder), which can cause tummy (abdominal) pain and yellow skin and eyes (jaundice)
- bone and joint pain
- priapism (a persistent and painful erection of the penis), which can sometimes last several hours
- leg ulcers (painful, open sores on the lower legs)
- strokes or transient ischaemic attacks (where the flow of blood to the brain is blocked or interrupted)
- a serious lung condition called acute chest syndrome, which can cause a fever, cough, chest pain, and breathing difficulties
- swelling of the spleen, which can cause shortness of breath, a rapid heartbeat, abdominal pain, a swollen tummy and worse anaemia
- vision problems, such as floaters, blurred or patchy vision, reduced night vision and occasionally sudden vision loss
- pulmonary hypertension (high blood pressure in the blood vessels that carry blood from the heart to the lungs)
- kidney or urinary problems, including blood in the urine and bedwetting
Sickle cell disease is caused by faulty genes that a child inherits from their parents.
It’s not caused by anything the parents did before or during the pregnancy and you can’t catch it from someone who has it.
How sickle cell disease is inherited
Genes come in pairs. You inherit one set from your mother and one set from your father.
To be born with sickle cell disease, a child has to inherit a copy of the faulty sickle cell gene from both of their parents.
This usually happens when both parents are “carriers” of the faulty gene – also known as having the sickle cell trait.
Sickle cell carriers don’t have sickle cell disease themselves, but there’s a chance they could have a child with the condition if their partner is also a carrier.
If both parents are sickle cell carriers, there’s a:
- 1 in 4 (25%) chance each child they have will not inherit any faulty genes and won’t have sickle cell disease or be able to pass it on
- 1 in 2 (50%) chance each child they have will just inherit a copy of the faulty gene from one parent and be a carrier
- 1 in 4 (25%) chance each child they have will inherit copies of the faulty gene from both parents and will be born with sickle cell disease
The Sickle Cell Society has more information about the inheritance of sickle cell disease, including what the risks are if a parent has sickle cell disease themselves.
Who’s most at risk of sickle cell disease?
Sickle cell disease mainly affects people with an African, Caribbean, Middle Eastern, Eastern Mediterranean and Asian family background.
In the UK, it’s most commonly seen in people of African and Caribbean backgrounds. It’s estimated that one in every 10 people in this group carries sickle cell.
A simple blood test will show whether you’re a carrier. This is done routinely during pregnancy and after birth, but you can ask to have the test at any time.
Read more about getting tested for the sickle cell trait and being a sickle cell carrier
How sickle cell disease affects the body
Your genes are the set of instructions found inside every cell in your body. They determine characteristics such as the colour of your eyes and hair.
People with sickle cell disease have a problem with the genes involved in the development of haemoglobin – a substance found in red blood cells that carry oxygen around the body.
Normal red blood cells are flexible and disc-shaped, but in sickle cell disease they can become rigid and shaped like a crescent or sickle because the haemoglobin inside them clumps together.
These unusual cells can cause symptoms of sickle cell disease because they don’t live as long as normal red blood cells and can become stuck in blood vessels.
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Sickle cell disease is usually detected during pregnancy or soon after birth.
Blood tests can also be carried out at any time to check for the condition or to see if you’re a sickle cell carrier and are at risk of having a child with the condition.
Screening during pregnancy
Screening to check if a baby is at risk of being born with sickle cell disease is offered to all pregnant women in England.
In parts of England where conditions such as sickle cell disease are more common, pregnant women are offered a blood test to check if they carry sickle cell.
In areas where these conditions are less common, a questionnaire about your family origins is used to determine whether you should have a blood test for sickle cell.
You can also ask to have the test even if your family origins don’t suggest your baby would be at high risk of sickle cell disease.
Screening should ideally be carried out before you’re 10 weeks pregnant, so you and your partner have time to consider the option of further tests to find out if your baby will be born with sickle cell disease.
Read more about screening for sickle cell disease during pregnancy.
In England, screening for sickle cell disease is offered as part of the newborn blood spot test (heel prick test).
This can help to:
- indicate whether your baby has sickle cell disease if pregnancy screening suggested they were at high risk but you decided not to have tests to confirm the diagnosis at the time
- identify any babies with sickle cell disease whose parents weren’t screened while pregnant
- show if your baby is a carrier of sickle cell and is at risk of having children of their own with the condition
- pick up certain other inherited conditions, such as cystic fibrosis
If newborn screening suggests your baby may have sickle cell disease, a second blood test will be carried out to confirm the diagnosis.
Read more about the newborn blood spot test.
Testing for the sickle cell carriers
A blood test can be done at any time to find out if you carry sickle cell and are at risk of having a child with sickle cell disease. This is also known as having the sickle cell trait.
Getting tested can be particularly useful if you have a family history of the condition or your partner is known to carry sickle cell.
If you think you could be a carrier, you can ask for a test from your GP surgery or nearest sickle cell and thalassaemia centre.
Both men and women can have the test.
Sickle cell disease usually requires lifelong treatment.
Some of the main treatments that may be used are outlined below:
Children and adults with sickle cell disease will be supported by a team of different healthcare professionals working together in a specialist sickle cell centre.
Your care team will help you learn more about the condition and work with you to come up with an individual care plan that takes into account all your needs and health concerns.
Preventing painful episodes
The main thing you can do to reduce your chances of experiencing a painful episode (sickle cell crisis) is to try avoiding possible triggers.
This may mean you need to:
- drink plenty of fluids to avoid dehydration
- wear appropriate clothing to stop you getting cold
- avoid sudden temperature changes, such as swimming in cold water
If you continue to experience episodes of pain, a medication called hydroxycarbamide (hydroxyurea) may be recommended. This is usually taken as a capsule once a day.
Hydroxycarbamide can lower the amount of other blood cells, such as white blood cells and platelets (clotting cells), so regular blood tests will usually be recommended to monitor your health.
If you experience a sickle cell crisis, you can usually manage it at home. The following can help:
- take over-the-counter painkillers, such as paracetamol or ibuprofen (aspirin should not be given to children under 16) – if the pain is more severe, your GP may prescribe stronger painkillers
- ensure you have plenty to drink
- use a warm towel or a heated pad to gently massage the affected body part – many pharmacies sell pads that can be used for this purpose
- try suitable distractions to take your mind off the pain– for example, children might like to read a story, watch a film or play their favourite computer game
Contact your GP if these measures don’t work or the pain is particularly severe. If this isn’t possible, take your child to your local accident and emergency (A&E) department.
Treatment with very strong painkillers (such as morphine) in hospital for a few days may be needed.
As people with sickle cell disease are more vulnerable to infections, treatment will usually be needed to reduce this risk.
Most people need to take a daily dose of antibiotics (usually penicillin), often for the rest of their life. Long-term use of antibiotics won’t pose any serious risks to your health.
Treatments for anaemia
Anaemia often causes few symptoms and may not require specific treatment.
However, dietary supplements such as folic acid (which helps stimulate the production of red blood cells) may sometimes be required to help improve anaemia if your child has a restricted diet, such as a vegetarian or vegan diet.
Anaemia caused by sickle cell disease isn’t the same as the more common iron deficiency anaemia. Don’t take iron supplements to treat it without seeking medical advice as they could be dangerous.
If anaemia is particularly severe or persistent, treatment with blood transfusions or hydroxycarbamide may be necessary.
Stem cell or bone marrow transplants
Stem cell or bone marrow transplants are the only cure for sickle cell disease, but they’re not done very often because of the significant risks involved.
Stem cells are special cells produced by bone marrow (a spongy tissue found in the centre of some bones) that can turn into different types of blood cells.
For a stem cell transplant, stem cells from a healthy donor are given through a drip into a vein. These cells then start to produce healthy red blood cells to replace the sickle cells.
A stem cell transplant is an intensive treatment that carries a number of risks. The main risk is graft versus host disease, which is a life-threatening problem where the transplanted cells start to attack the other cells in your body.
Stem cell transplants are generally only considered in children with sickle cell disease who have severe symptoms that haven’t responded to other treatments, when the long-term benefits of a transplant are thought to outweigh the possible risks.
Treating other problems
Sickle cell disease can also cause a number of other problems that may need to be treated. For example:
- a short course of hormonal medication may be prescribed to help trigger puberty in children with delayed puberty
- gallstones may be treated with gallbladder removal surgery
- bone and joint pain can be treated with painkillers, although more severe cases may require surgery
- persistent priapism (a persistent and painful erection) may require medication to stimulate blood flow or using a needle to drain blood from the penis – read more about treatments for priapism
- leg ulcers can be treated by cleaning the ulcer and dressing it with a bandage (read more about treating leg ulcers)
- people at increased risk of having a stroke, or those who’ve had a stroke, may need regular blood transfusions or treatment with hydroxycarbamide
- acute chest syndrome (a serious lung condition) usually requires emergency treatment with antibiotics, blood transfusions, oxygen and fluids given into a vein – hydroxycarbamide may be needed to prevent further episodes
People who need a lot of blood transfusions may also need to take medication to reduce the amount of iron in their blood to safe levels. This is called chelation therapy.
Living with sickle cell disease
There are a number of things you can do, and precautions you need to take, to ensure you stay as healthy as possible if you have sickle cell disease.
You can reduce your risk of experiencing painful episodes (sickle cell crises) by avoiding things that can trigger them. You should try to:
- drink plenty of fluids, particularly during hot weather – dehydration increases the risk of a sickle cell crisis
- avoid extreme temperatures – you should dress appropriately for the weather and avoid sudden temperature changes such as swimming in cold water
- be careful at high altitudes – the lack of oxygen at high altitudes may trigger a crisis (travelling by plane shouldn’t be a problem because planes are pressurised to maintain a steady oxygen level)
- avoid very strenuous exercise – people with sickle cell disease should be active, but intense activities that cause you to become seriously out of breath are best avoided
- avoid alcohol and smoking – alcohol can cause you to become dehydrated and smoking can trigger a serious lung condition called acute chest syndrome
- relax – stress can trigger a sickle cell crisis, so it may help to learn relaxation techniques such as breathing exercises
Your care team can give you more advice about avoiding triggers.
You’ll usually be given antibiotics and advised to have vaccinations to help prevent most serious infections, but there are also things you can do to reduce your risk.
For example, you should make sure you follow good food hygiene measures to prevent food poisoning.
- wash your hands with soap and water regularly – particularly after going to the toilet and before handling food
- cook food thoroughly – particularly ensure reheated food, meat and most types of seafood are steaming hot in the middle before eating them
- store food correctly – make sure chilled food is kept in the fridge and cooked leftovers that you intend to reheat later aren’t left out for long
You should also make sure you speak to your GP or care team if you’re planning on travelling aboard, as this may mean you need extra medication or vaccinations. You may also need to take extra food and water precautions.
Pregnancy and contraception
Women with sickle cell disease can have a healthy pregnancy, but it’s a good idea to speak to your care team for advice first because:
- it may be useful to find out if your partner is a carrier of sickle cell and to discuss what the implications of this are with a counsellor
- some sickle cell disease medications, such as hydroxycarbamide, could potentially harm an unborn baby and may need to be stopped before trying to get pregnant
- there’s an increased risk of problems such as anaemia, sickle cell pain, miscarriage and pre-eclampsia during pregnancy
- you may need extra monitoring and treatment during pregnancy to help prevent problems
If you’re not planning a pregnancy, you should use a reliable form of contraception.
It’s important to let your care team know if you need to have an operation under general anaesthetic at any point. You should also tell your surgeon that you have sickle cell disease.
This is because general anaesthetic can cause problems for people with sickle cell disease, including an increased risk of experiencing a sickle cell crisis.
You may need close monitoring during surgery to ensure you’re getting enough fluids and oxygen and are kept warm.
Sometimes you may be need a blood transfusion beforehand to reduce the risk of complications.
When to get medical advice
It’s important to make sure you know when to get medical advice and where to go because sickle cell disease can cause a number of serious problems that can appear suddenly.
Problems to look out for include:
- a high temperature (fever) or 38C (100.4F) or above
- severe pain that isn’t responding to treatment at home
- a very severe headache, dizziness or stiff neck
- breathing difficulties
- very pale skin or lips
- sudden swelling in the tummy
- a painful erection (priapism) lasting more than two hours
- confusion, drowsiness or slurred speech
- seizures (fits)
- weakness on one or both sides of the body
- changes in vision or sudden vision loss
Contact your GP or care team immediately if you develop any of the above symptoms. If this isn’t possible, go to your nearest accident and emergency (A&E) department. If you aren’t well enough to travel to hospital yourself, dial 999 for an ambulance.
Make sure that the medical staff looking after you are aware that you have sickle cell disease.
Sickle Cell Society
Finding out as much as possible about sickle cell disease may help you feel more in control of your condition.
The Sickle Cell Society is a UK-based charity for people with sickle cell disease and its website contains a wide range of useful information, including news about ongoing research into the disorder.
Carriers of sickle cell
If you’re a carrier of sickle cell it means you carry one of the faulty genes that causes sickle cell disease, but you don’t have the condition yourself.
It’s also known as having the sickle cell trait.
People who carry sickle cell won’t develop sickle cell disease, but may be at risk of having a child with the condition and may occasionally need to take precautions to stop them becoming unwell.
You can find out if you’re a carrier of sickle cell by having a simple blood test.
Who can be a sickle cell carrier?
Anyone can be a carrier of sickle cell, but it’s much more common in people from certain ethnic backgrounds.
People with family members originally from the following parts of the world are most at risk:
- the Caribbean
- the Middle East
- the eastern Mediterranean
In the UK, most people who carry sickle cell have an African or Caribbean family background. It’s estimated that around 1 in 10 people in this group may be a carrier.
Testing for the sickle cell carriers
Screening for sickle cell disease is offered to all pregnant women in England, although most women will be at low risk and won’t need to have a blood test to check if they’re a carrier.
Read more about screening for sickle cell disease in pregnancy.
Anyone can ask to have a free test to find out if they’re a carrier at any point. This can be useful if:
- you want to find out if you’re at risk of having a child with sickle cell disease
- you have a family history of sickle cell disease or carrying sickle cell
- your partner carries sickle cell
You can request the test from your GP surgery or nearest genetic counsellor who will discuss the result and implications with you if you’re found to carry sickle cell.
If you carry sickle cell, you’re at risk of having children with sickle cell disease, although this can only happen if your partner is also a carrier or has sickle cell disease themselves.
If you’re planning to have a child and you know you’re a carrier, it’s a good idea for your partner to be tested.
If you and your partner both carry sickle cell, there’s a:
- 1 in 4 (25%) chance each child you have will not have sickle cell disease or be a carrier
- 1 in 2 (50%) chance each child you have will be a carrier but won’t have sickle cell disease
- 1 in 4 (25%) chance each child you have will be born with sickle cell disease
If both of you are carriers and you’re planning to have a baby, talk to your GP about getting a referral to a genetic counsellor who can explain the risks to your children and what your options are.
- having tests during pregnancy to see if your baby will have sickle cell disease
- adopting a child
- trying in vitro fertilisation (IVF) with a donor egg or sperm
- trying pre-implantation genetic diagnosis (PGD)
PGD is similar to IVF, but the resulting embryos are tested to check that they don’t have sickle cell disease before they’re implanted in the womb. The Human Fertilisation and Embryology Authority (HFEA) has more information about PGD.
Rare health risks
You’re not at risk of developing sickle cell disease if you carry sickle cell.
The only time you may be at risk of health problems is in rare cases where you might not get enough oxygen, such as:
- having surgery under general anaesthetic – make sure medical staff are aware you carry sickle cell before your operation so they can ensure you get enough oxygen
- during extreme sports such as deep sea diving and climbing at high altitudes – if you do sports like these, ensure you’re never short of oxygen
- during regular, intensive physical activity – make sure you drink plenty of fluids during training and avoid extreme exhaustion
There’s also a very small risk of developing kidney problems associated with carrying sickle cell.
Apart from these uncommon situations, you can lead a completely normal and healthy life if you’re a sickle cell carrier.
Carriers of other blood disorders
People who are carriers of sickle cell are also at risk of having a child with a blood disorder if their partner is a carrier of a different type of blood disorder.