Sickle Cell Disease: The Complete Guide to Symptoms, Crises, Treatment and Living Well

Sickle cell disease affects millions of people worldwide, yet many families still learn about it in an emergency department. This guide explains how it works, how to prevent crises, and the warning signs that cannot wait.

Imagine your eight-year-old wakes at 2am crying that her legs hurt. It is the third time this month. You give her water and painkillers and hold her, wondering whether to wait until morning. Then you notice she is breathing fast and her temperature is 38.6°C. Knowing which signs mean “go now” can change the outcome.

What is sickle cell disease?

Sickle cell disease (SCD) is a group of inherited blood conditions. It affects haemoglobin, the protein in red blood cells that carries oxygen. People with SCD produce an abnormal form called haemoglobin S. When oxygen levels drop, haemoglobin S can cause red blood cells to become stiff and curved like a sickle or crescent.,Sickled cells do not flow smoothly. They can block small blood vessels, causing pain and damaging organs, and they break down faster than normal cells, causing anaemia. The condition is lifelong, but good care has transformed survival and quality of life.

Who is affected?

SCD is most common in people whose families come from sub-Saharan Africa, the Caribbean, the Middle East, India and the Mediterranean. Nigeria has the largest number of affected births in the world, and the condition is also one of the most common inherited disorders in the United States, the United Kingdom and Brazil. The World Health Organization estimates that hundreds of thousands of babies are born with SCD every year.

How it is inherited

Everyone inherits two copies of the haemoglobin gene, one from each parent. A person with one normal gene (A) and one sickle gene (S) has sickle cell trait (AS). They usually have no symptoms but can pass the gene on. A person with two sickle genes (SS) has sickle cell anaemia, the most common and often most severe form. Other combinations, such as SC or S-beta thalassaemia, also cause sickle cell disease.,When both parents carry the trait (AS), each pregnancy has a one in four chance of a child with SS, a one in two chance of a child with the trait, and a one in four chance of a child with AA. This is why genotype testing before marriage or pregnancy is encouraged in many countries.

Sickle cell trait

Sickle cell trait is not a mild form of the disease. Most carriers live normal, healthy lives. Rarely, under extreme conditions such as severe dehydration, very intense exercise or high altitude, people with the trait can develop complications, so athletes and military recruits are advised to stay well hydrated and rest when unwell. Knowing your status matters most for family planning.

How it is diagnosed

Many countries screen newborns with a heel-prick blood test, which allows treatment to start before symptoms appear. Where newborn screening is not routine, diagnosis often follows a first painful episode, swelling of the hands and feet, or repeated infections in early childhood.,Haemoglobin electrophoresis or high-performance liquid chromatography (HPLC) confirms the type. A full blood count usually shows anaemia and may show a raised reticulocyte count. Prenatal testing is available for couples who are both carriers.

Early signs in babies and children

• Painful swelling of the hands and feet (dactylitis), often the first sign at six months to two years
• Pale skin or yellow eyes from anaemia and jaundice
• Frequent infections
• Irritability, poor feeding or failure to thrive
• Sudden pallor and a swollen tummy (a sign of splenic sequestration, an emergency)

Pain crises

A vaso-occlusive or pain crisis happens when sickled cells block blood flow to bones, joints or organs. Pain can be in the back, chest, arms, legs or abdomen, and ranges from mild to severe. Crises can last hours to days. Common triggers include dehydration, cold, infection, stress, overexertion, alcohol and sudden changes in temperature, though often there is no clear cause.,Mild crises can sometimes be managed at home with fluids, rest, warmth and pain relief as agreed in your care plan. Severe pain, or pain not controlled with home medicines, needs hospital care, where guidelines recommend effective pain relief within 30 to 60 minutes of arrival.

Acute chest syndrome

Acute chest syndrome is a serious lung complication and a leading cause of death in SCD. It often starts with a pain crisis or infection and causes chest pain, cough, fever, fast breathing and low oxygen levels. It can worsen quickly. Anyone with SCD who develops chest pain, breathing difficulty or a fever with a cough needs urgent hospital assessment. Treatment may include oxygen, antibiotics, incentive spirometry and blood transfusion.

Infection risk and the spleen

The spleen helps fight certain bacteria. In SCD, sickled cells damage the spleen early in life, often by the age of five, leaving children highly vulnerable to serious infections such as pneumococcal sepsis and meningitis. A fever can be the first sign of a life-threatening infection.,This is why children with SCD are usually given daily penicillin from early infancy and why vaccinations, including pneumococcal, meningococcal, Hib, and yearly flu vaccines, are so important. Any temperature of 38°C or more in a person with SCD needs urgent medical assessment, the same day, without waiting to see if it settles.

Splenic sequestration

In young children, sickled cells can suddenly become trapped in the spleen, which swells rapidly and pulls blood out of circulation. Signs include sudden pallor, weakness, a swollen and tender left side of the tummy, and fast heartbeat. It is an emergency that can be fatal within hours. Parents are often taught to feel their child’s spleen daily so they know what is normal.

Stroke

Children with sickle cell anaemia have a much higher risk of stroke than other children. Signs include sudden weakness or numbness on one side, facial droop, slurred speech, confusion, a severe headache, a seizure or loss of vision. Call emergency services immediately.,Transcranial Doppler (TCD) ultrasound, a painless scan of blood flow in the brain, is recommended every year for children aged 2 to 16 with HbSS or HbS-beta zero thalassaemia. Children found to be at high risk can be started on regular blood transfusions or hydroxyurea, which greatly reduces stroke risk.

Other complications

• Anaemia and fatigue
• Gallstones from rapid breakdown of red cells
• Priapism (painful, prolonged erection) needing urgent care if it lasts more than 2 hours
• Avascular necrosis of the hip or shoulder
• Leg ulcers
• Eye damage (retinopathy); yearly eye checks are advised from late childhood
• Kidney damage and high blood pressure
• Pulmonary hypertension
• Delayed growth and puberty
• Complications in pregnancy

Hydroxyurea (hydroxycarbamide)

Hydroxyurea is a daily oral medicine that increases levels of foetal haemoglobin, which does not sickle. It reduces pain crises, acute chest syndrome, hospital admissions and the need for transfusions, and it improves survival. Guidelines now recommend offering it to children with sickle cell anaemia from nine months of age, and to adults with frequent crises.,Regular blood tests are needed to monitor blood counts. Hydroxyurea is affordable and on the WHO list of essential medicines, and access is expanding in Africa. It should not be taken in pregnancy, so effective contraception is important.

Blood transfusions

Transfusions are used in emergencies such as severe anaemia, acute chest syndrome and stroke, and regularly to prevent stroke in high-risk children. Long-term transfusions can cause iron to build up in the body, so iron levels are monitored and chelation medicines may be needed to remove excess iron. Exchange transfusion, where sickled blood is removed and replaced, is used in some serious complications.

Newer treatments

Several newer medicines aim to reduce crises or anaemia, including L-glutamine and crizanlizumab in some countries. Availability and evidence vary, and some approvals have been reviewed as new data emerged.,Bone marrow (stem cell) transplant from a matched sibling can cure SCD, especially in children, though it carries serious risks. Gene therapies, including exa-cel (Casgevy) and lovo-cel (Lyfgenia), approved in the United States, the United Kingdom and other countries since 2023, offer a potential cure for some patients aged 12 and over. They are very expensive and require intensive treatment, so access remains limited worldwide.

Your sickle cell care plan

Everyone with SCD should have an individual care plan agreed with their specialist team. It should cover usual pain medicines and doses, what to do at home, when to go to hospital, contact numbers, and baseline blood results such as usual haemoglobin. Carry a copy or keep it on your phone, and show it when you attend an emergency department.

Preventing crises day to day

• Drink plenty of water throughout the day, more in hot weather, during exercise and when unwell
• Keep warm; avoid sudden cold, swimming in cold water and air-conditioning blasts
• Take daily penicillin and folic acid if prescribed
• Keep vaccinations up to date, including yearly flu vaccine
• Rest when tired and pace activity
• Avoid alcohol and smoking
• Manage stress with sleep, support and relaxation
• Use a malaria net and preventive medicines in malaria areas
• Take extra care when flying or at high altitude, and discuss travel plans with your team

Managing pain at home

Start your agreed pain relief early, at the first sign of a crisis, rather than waiting for pain to become severe. Drink extra fluids, use warm compresses or a warm bath, rest, and use distraction such as music, films or breathing exercises. Gentle massage may help.,Avoid cold packs, which can make sickling worse. Go to hospital if pain is not controlled by your home medicines, if you have a fever, breathing difficulty, chest pain, a swollen tummy, weakness or any stroke symptoms.

Getting fair treatment in hospital

People with SCD report being disbelieved about pain, waiting too long for pain relief, or being labelled as “drug-seeking”. Reports in several countries, including the UK parliamentary inquiry No One’s Listening (2021), found that this contributed to avoidable harm.,You have the right to timely pain relief, to be listened to, and to have your care plan followed. Bring your care plan, ask for the haematology team to be contacted, and bring a relative or friend to advocate for you if you can. If care falls short, raise it with the ward manager or patient advocacy service.

Diet and nutrition

A balanced diet with plenty of fruit, vegetables, whole grains and protein supports growth and health. Folic acid helps the body make new red blood cells. Do not take iron supplements unless a blood test shows iron deficiency, as people who have frequent transfusions may already have too much iron. Vitamin D and calcium are important for bone health. Ask your team before taking herbal remedies.

Exercise and sport

Regular moderate exercise is good for people with SCD. Build up gradually, drink water before, during and after activity, take breaks, avoid becoming overheated or cold, and stop if you feel pain or very tired. Swimming is fine in a heated pool. Let teachers and coaches know about the condition and what to do if a crisis starts.

School and children

Children with SCD may miss school due to crises and appointments. Give the school a copy of the care plan, and ask that your child can drink water freely, use the toilet whenever needed (because the kidneys produce more dilute urine), stay warm, and rest when tired. Many children need extra support to catch up. Fatigue and mild learning difficulties after silent strokes are common, so ask about assessments if your child is struggling.

Mental health and wellbeing

Living with chronic pain, unpredictable crises and stigma can affect mood and relationships. Depression and anxiety are common and treatable. Psychological support, peer support groups and patient organisations can make a real difference. Talk to your nurse or care team about how you are feeling, not just your physical symptoms.

Pregnancy and sickle cell disease

Many women with SCD have healthy pregnancies, but the risks of crises, infections, blood clots, pre-eclampsia, miscarriage and small babies are higher. Plan pregnancy with your specialist team where possible. Hydroxyurea should usually be stopped before conception, and folic acid at a higher dose is often recommended.,Care should be shared between obstetric and haematology teams, with closer monitoring, low-dose aspirin from 12 weeks in many cases, and a plan for pain management in labour. Your partner can be tested to find out the chance of your baby inheriting SCD.

Relationships, marriage and genotype testing

Knowing your genotype, and your partner’s, before starting a family allows informed choices. Two carriers can still choose to have children together; options include prenatal testing, pre-implantation genetic testing with IVF in some settings, or deciding to accept the risk. Counselling should be supportive and free from stigma. A person with SCD can and does have loving relationships, careers and families.

Adults living with sickle cell disease

With good care, many people with SCD now live into their 50s, 60s and beyond in high-income countries, though life expectancy remains much shorter in settings without newborn screening, penicillin and hydroxyurea. The move from children’s to adult services is a vulnerable time; ask for a transition plan in the teenage years so you know your adult team before you need them.

Emergency signs: go to hospital now

• Temperature of 38°C or higher
• Chest pain, cough or difficulty breathing
• Pain not controlled by home medicines
• Sudden weakness, numbness, facial droop, slurred speech, severe headache or seizure
• Sudden pallor, extreme tiredness or a swollen tummy
• Erection lasting more than 2 hours
• Yellow eyes with dark urine and tiredness that is getting worse
• Vomiting and unable to keep fluids down

Understanding your blood results

People with SCD usually have a lower haemoglobin than others, and their “normal” may be 60 to 90 g/L for HbSS, higher for HbSC. Knowing your baseline helps staff judge whether a result is unusual for you. A sudden drop of 20 g/L or more from your baseline is significant.

Other common tests include the reticulocyte count (young red cells, which rise as the bone marrow works harder), bilirubin (raised from red cell breakdown), ferritin (iron stores, especially if you have transfusions), kidney function and urine protein. Ask your team to explain your results and keep a record.

Travel and climate

Hot climates increase dehydration, and cold weather can trigger crises. On long flights, drink water regularly, move around the cabin, keep warm, and avoid alcohol. Most people with SCD fly safely on commercial aircraft, but discuss travel with your team, especially if you have had recent complications. Take your care plan, medicines in hand luggage, and travel insurance that covers your condition. Malaria can be very dangerous for people with SCD, so strict bite prevention and preventive tablets are essential when visiting malaria areas.

Support for families and carers

Caring for a child or partner with SCD can be exhausting and frightening. Siblings may feel left out during hospital stays. Patient organisations offer peer support, practical advice and advocacy. Ask about social work support, school liaison and respite where available, and look after your own health and sleep too.

World Sickle Cell Day

World Sickle Cell Day is marked on 19 June each year, recognised by the United Nations, to raise awareness, encourage genotype testing and push for better access to newborn screening, preventive medicines and modern treatment worldwide. Many organisations hold free testing and education events.

Questions to ask at your next clinic visit

• Am I or my child eligible for hydroxyurea, and what are the benefits and side effects?
• When is the next transcranial Doppler scan due?
• What should my pain plan include, and what dose should I take at home?
• Are my vaccinations up to date, including flu and pneumococcal?
• When should I have eye, kidney and heart checks?
• What is my baseline haemoglobin?
• Am I eligible for any clinical trials or new treatments?
• Who do I call out of hours?

Sickle cell disease and COVID-19 and other infections

People with SCD are at higher risk of severe illness from respiratory infections including flu and COVID-19. Vaccination, good hand hygiene, and early medical review for fever or breathing symptoms are the best protection. Do not delay seeking help because you are worried about busy hospitals.

Ageing with sickle cell disease

As more people with SCD live into later adulthood, complications such as kidney disease, pulmonary hypertension, heart problems and joint damage become more important. Regular screening, blood pressure control, kidney protection with medicines where needed, and joint care help. Staying connected with a specialist team throughout adult life gives the best chance of catching problems early.

Frequently asked questions

Can sickle cell disease be cured?

Bone marrow transplant and newer gene therapies can cure some people, but they carry risks and are not widely available. Most people manage SCD long term with preventive care, hydroxyurea and good crisis management.

Can sickle cell trait turn into sickle cell disease?

No. Trait and disease are determined by your genes at birth and cannot change.

Is sickle cell disease contagious?

No. It is inherited from parents and cannot be caught from another person.

Why is water so important?

Dehydration makes blood thicker and increases sickling. Staying well hydrated is one of the simplest ways to reduce crises.

Can people with SCD get vaccinated?

Yes. Vaccines are especially important because of the increased risk of serious infections.

Can adults with sickle cell disease work full time?

Many do. Flexible working, access to water, warm working conditions and understanding about appointments help. In many countries, SCD is recognised as a disability, giving rights to reasonable adjustments.

But we have always managed crises at home. Why change?

Home care works for many mild crises. But fever, chest symptoms, stroke signs and a swelling spleen can become life-threatening within hours. Combining good home care with a clear plan for when to go to hospital, and daily preventive treatment, is what keeps people with SCD well for longer.

Related: Sickle cell crisis care · Children with SCD · Premarital genotype checks · Loving a partner with SCD

Sources: World Health Organization, US Centers for Disease Control and Prevention, National Heart, Lung, and Blood Institute, National Institute for Health and Care Excellence, Sickle Cell Society, American Society of Hematology.