EVIDENCE-BASEDAWAITING CLINICIAN REVIEW

Sickle cell disease

Sickle cell disease (SCD) is a group of inherited haemoglobin disorders in which abnormal haemoglobin makes red blood cells prone to sickling. Sickled cells can break down prematurely, causing chronic haemolytic anaemia, and can block small blood vessels, causing pain and organ injury.

At a glance

Quick facts

Condition snapshot
Category
Inherited haemoglobin disorder
Inheritance
Autosomal recessive
Core mechanisms
Haemolysis + vaso-occlusion
Major emergencies
Pain crisis · acute chest · stroke · infection
Disease-modifying care
Hydroxyurea · transfusion
Curative options
Transplant / gene therapy in selected patients

Names & terminology

How this entity may be named or searched

Canonical name
Sickle cell disease (SCD) is the umbrella term for several genotypes.
Sickle cell anaemia
Usually refers specifically to HbSS, one of the most severe forms of SCD.
Sickle cell trait
Carrier state with one sickle haemoglobin gene; it is not the same as sickle cell disease.
Haemoglobin variants
HbSS, HbSC and HbS-beta-thalassaemia are among the common disease genotypes.

Structured entity profile

Clinical profile

Condition data
CauseInherited abnormal haemoglobinPathogenic HBB variants lead to haemoglobin S and red-cell sickling.
Core pathologyHaemolysis + vaso-occlusionPremature red-cell breakdown causes anaemia; blocked microcirculation causes pain and organ injury.
DiagnosisHaemoglobin analysisNewborn screening and confirmatory haemoglobin testing can diagnose SCD before symptoms begin.
Acute risksPain · infection · acute chest · strokeSome complications are medical emergencies.
Long-term carePreventive + disease-modifyingVaccination, infection prevention, hydroxyurea, screening and transfusion are used according to genotype and risk.
Curative therapyAvailable to selected patientsHaematopoietic stem-cell transplant and gene-based therapies can be curative in some settings.

Overview

SCD is present from birth and includes several genotypes. HbSS is commonly called sickle cell anaemia; HbSC disease and sickle beta-thalassaemia are other forms. Sickle cell trait is different and usually does not produce the clinical syndrome of SCD. [1] [2]

WHO estimated that 7.74 million people were living with SCD in 2021 and about 515,000 affected babies were born that year. Nearly 80% of the global burden is in sub-Saharan Africa, where gaps in newborn screening and comprehensive care contribute to avoidable childhood illness and death. [1]

Symptoms and warning signs

Symptoms vary widely by genotype and person. Chronic anaemia can cause fatigue, pallor and jaundice, while vaso-occlusion can cause acute or chronic pain. Important complications include acute chest syndrome, severe infection, stroke, splenic sequestration, priapism and progressive organ damage. [1] [2]

SYMPTOM MATRIX

SCD combines chronic symptoms with time-sensitive acute complications

Fever, chest symptoms and neurologic deficits require particular urgency.

Inherited blood disorder
Common / recurring features
  • Anaemia and fatigue
  • Jaundice
  • Acute pain episodes
  • Chronic pain in some patients
  • Reduced exercise tolerance
Long-term complications
  • Kidney, eye or bone damage
  • Pulmonary complications
  • Gallstones
  • Priapism
  • Pregnancy complications
Urgent warning signs
  • Fever or suspected serious infection
  • Chest pain or difficulty breathing
  • Sudden weakness, speech or vision change
  • Severe pallor or sudden abdominal enlargement
  • Prolonged painful erection

Acute chest syndrome, stroke, severe infection and splenic sequestration can be life-threatening.

Diagnosis

SCD is diagnosed using blood tests that identify haemoglobin variants, such as high-performance liquid chromatography, electrophoresis or equivalent validated methods. Genetic testing can clarify genotype when needed. [1] [2]

Newborn screening makes it possible to identify affected infants before major complications appear, allowing early education, infection prevention and specialist follow-up. Screening programmes and access to confirmatory testing vary by country. [1] [2]

Diagnostic pathway

Confirm the haemoglobin genotype — then establish a preventive care pathway

Diagnosis is only the first step; early linkage to comprehensive care changes outcomes.

Early diagnosis
1Screen or test haemoglobinUse newborn screening or diagnostic haemoglobin testing when SCD is suspected.
2Confirm the genotypeDifferentiate HbSS, HbSC, HbS-beta-thalassaemia and other variants.
3Establish baseline riskAssess anaemia, infection history, pain, organ function and stroke risk according to age.
4Start preventive follow-upLink vaccination, infection prevention, hydroxyurea assessment, stroke screening and family education.
Core diagnosisHaemoglobin analysisHPLC / electrophoresis or equivalent
Stroke screeningTCD in selected childrenrisk stratification

Sickle cell trait and sickle cell disease should be clearly distinguished when interpreting a haemoglobin result.

Infection risk and fever

Many people with severe SCD develop impaired splenic function, increasing susceptibility to serious bacterial infection. Vaccination and age-appropriate infection prevention are central parts of care. Fever may be the first sign of a life-threatening infection and should be assessed promptly according to age and local protocol. [2] [3]

Stroke risk in children

Sickle cell anaemia substantially increases childhood stroke risk. CDC recommends annual transcranial Doppler ultrasound for children with sickle cell anaemia from age 2 through 16 years to identify high-risk cerebral blood-flow patterns and guide preventive treatment. [4]

Treatment and management

Management aims to prevent complications and treat acute events early. Hydroxyurea increases fetal haemoglobin and can reduce vaso-occlusive pain, acute chest syndrome and other complications in many patients. Vaccination, infection prevention, screening and individualized pain plans are also important. [1] [3]

Blood transfusion is used for selected acute complications and for prevention of stroke in some high-risk patients. Haematopoietic stem-cell transplantation can cure SCD in selected people, and gene-based therapies are now available in some health systems, although access and long-term implementation remain limited globally. [1] [3]

Treatment & care hub

SCD care is preventive, disease-modifying and emergency-ready

The goal is not only to treat pain episodes but to prevent infection, stroke and cumulative organ damage.

Comprehensive care
Disease modificationCore for many

Hydroxyurea

Raises fetal haemoglobin and can reduce vaso-occlusive events and acute chest syndrome.

PreventionLong-term

Vaccination + screening

Preventive care includes infection protection, organ monitoring and age-appropriate stroke screening.

TransfusionIndication-based

Acute and preventive transfusion

Used for selected severe complications and in some patients at high stroke risk.

Curative therapySelected patients

Transplant or gene therapy

Curative options require specialist assessment, infrastructure and careful risk-benefit discussion.

Prevent infection→Reduce crises→Screen complications→Escalate emergencies

Individual treatment depends on genotype, age, complication history, pregnancy status and local specialist resources.

Acute pain episodes

Vaso-occlusive pain should be assessed promptly and treated with timely analgesia while clinicians look for complications or alternative diagnoses. Hydration should be guided by clinical status rather than given indiscriminately, and new chest symptoms, hypoxaemia or fever require evaluation for acute chest syndrome or infection. [3]

Pregnancy and sickle cell disease

Pregnancy with SCD carries increased risks for both the pregnant person and fetus, including pain crises, infection, hypertensive complications, fetal growth problems and preterm birth. Preconception and antenatal care should involve obstetric and haematology expertise where available. [1]

Global burden · WHO 2025

Sickle cell disease is concentrated in sub-Saharan Africa

WHO estimates show a large and under-recognized global burden, particularly among children.

WHO Sickle-cell disease fact sheet, 6 Aug 2025 ↗
People living with SCD7.74 millionestimated, 2021
Affected births515,000
Share in sub-Saharan Africanearly 80%
Under-5 deaths81,100
Scope: WHO figures are modelled 2021 estimates; burden is likely under-recorded in routine death certification.

Common questions

Frequently asked questions

Reference content

Sources

  1. WHO — Sickle-cell disease fact sheet, 6 August 2025
  2. CDC — About Sickle Cell Disease, reviewed 7 August 2026
  3. CDC — Prevention and Treatment of SCD Complications, reviewed 7 August 2026
  4. CDC — Complications of SCD: Stroke, reviewed 7 August 2026

This article is based on trusted medical sources and is awaiting clinician review. It is not a substitute for personalized medical advice.