Sickle Cell Disease: Symptoms, Crises & NHS Treatment

Sickle cell disease (SCD) is an inherited blood disorder affecting the shape of red blood cells. In the UK, it predominantly affects people of African, Caribbean, Middle Eastern, Mediterranean and South Asian heritage. This guide covers symptoms, the sickle cell crisis, NHS management, and how to live well with SCD.

What Is Sickle Cell Disease?

Sickle cell disease is caused by a mutation in the HBB gene, which codes for beta-globin haemoglobin. This produces abnormal haemoglobin S (HbS). When haemoglobin S loses oxygen, it polymerises and causes red blood cells to deform into a rigid sickle shape.

Sickled cells are fragile and break down prematurely (haemolytic anaemia). They also stick to blood vessel walls, causing blockages that restrict blood flow and oxygen delivery to tissues and organs — a process known as vaso-occlusion.

SCD is a recessive condition: a child must inherit an HbS gene from both parents to develop the disease. If only one copy is inherited, the child has sickle cell trait (HbAS), which is generally asymptomatic.

Types of Sickle Cell Disease

• HbSS (sickle cell anaemia) — two HbS copies; the most common and most severe form
• HbSC disease — one HbS and one HbC gene; often milder but still causes significant complications
• HbS beta-thalassaemia — combination of HbS and a thalassaemia mutation

Symptoms of Sickle Cell Disease

Symptoms typically begin from around 5-6 months of age, when foetal haemoglobin is replaced by adult haemoglobin. Common features include:

• Chronic anaemia — fatigue, pallor, jaundice, and shortness of breath due to shortened red blood cell lifespan
• Painful crises (vaso-occlusive episodes) — severe pain in bones, chest, abdomen or joints
• Swollen hands and feet (dactylitis) — a common first sign in infants
• Delayed growth and puberty in children
• Increased susceptibility to infection — due to functional asplenia
• Acute chest syndrome — chest pain, fever, falling oxygen saturation; a medical emergency
• Stroke — occurs in around 10% of children with HbSS without preventive treatment
• Priapism — prolonged, painful erection requiring urgent treatment
• Leg ulcers, eye disease, avascular necrosis of joints

The Sickle Cell Crisis

A vaso-occlusive crisis (VOC) is the most common reason people with SCD attend A&E. Pain can be sudden and severe, typically in the limbs, spine, ribs or pelvis. It is caused by sickled cells obstructing small blood vessels and causing localised tissue ischaemia.

Common triggers include cold weather, dehydration, physical exertion, infection, stress, and altitude. Many crises have no identifiable trigger.

NHS Diagnosis

In England, all newborns are screened for SCD at 5-8 days via the newborn blood spot (heel prick) test. Screening is also offered to pregnant women as part of antenatal care. In older children or adults, diagnosis involves a full blood count, blood film, and haemoglobin electrophoresis or HPLC to confirm the genotype.

NHS Treatment and Management

Preventive Treatment

Hydroxycarbamide (hydroxyurea) is the most important disease-modifying treatment for SCD. It increases foetal haemoglobin (HbF) production, which inhibits HbS polymerisation and reduces sickling. NICE recommends hydroxycarbamide for adults and children with frequent or severe VOCs, ACS, or stroke risk.

Penicillin prophylaxis is given from around 3 months of age until at least age 5, due to the risk of overwhelming bacterial infection from functional asplenia. Vaccinations are critically important — enhanced schedules include pneumococcal, meningococcal, and Hib vaccines.

Folic acid supplementation (5mg daily) compensates for increased red blood cell turnover.

Regular blood transfusions are used for children with elevated transcranial Doppler (TCD) velocities indicating stroke risk, and for those who have had a stroke. TCD screening is recommended annually from age 2-16.

Newer Disease-Modifying Therapies

Voxelotor (Oxbryta) inhibits HbS polymerisation and was approved by NICE in 2023 for adults and adolescents (12+). Crizanlizumab (Adakveo) is a monoclonal antibody targeting P-selectin that reduces VOC frequency, available on the NHS for adults and adolescents aged 16+ with three or more VOCs per year.

Curative Treatment

Allogeneic haematopoietic stem cell transplant (HSCT) remains the only established cure for SCD. It is recommended for children with severe disease who have a matched sibling donor. Gene therapy is an emerging area; NICE appraisal for NHS use is ongoing.

Managing Acute Pain Crises

Per NICE NG143, patients presenting to A&E with sickle cell pain should receive pain assessment within 30 minutes of arrival and analgesia within 60 minutes, with reassessment every 30 minutes until pain is controlled. Oxygen is only given if SpO2 is below 94%.

Living With Sickle Cell Disease

• Stay well-hydrated — dehydration is a major crisis trigger; aim for 2-3 litres of water per day
• Keep warm — cold is a potent sickling trigger; dress in layers and avoid cold water swimming
• Avoid excessive exertion — exercise at a moderate pace; avoid exercising at altitude or in extreme heat
• Take medications as prescribed — including hydroxycarbamide, penicillin, folic acid, and vaccinations
• Carry a Sickle Cell Emergency Health Care Plan — invaluable in A&E settings
• Recognise ACS and priapism early — these require immediate emergency care
• Inform schools, employers, and travel insurers of your condition

Sickle Cell Trait

Sickle cell trait (HbAS) affects around 300,000 people in the UK. Carriers generally have no symptoms and live normally. Genetic counselling is recommended for couples both found to carry the trait, as each pregnancy then carries a 1-in-4 chance of SCD.