Sickle cell anemia

Last updated: March 24, 2022

Summarytoggle arrow icon

Sickle cell syndromes are hereditary hemoglobinopathies. Homozygous sickle cell anemia (HbSS, autosomal recessive) is the most common variant of the sickle cell syndromes and occurs predominantly in individuals of African and East Mediterranean descent. Sickle cell trait occurs in heterozygous carriers (HbSA). Other rare variants of sickle cell syndrome occur in individuals with one HbS allele and one other allele (HbC or Hb-β thalassemia). A point mutation in the beta chain of hemoglobin leads to substitution of glutamic acid by valine, thus changing the structure (and properties) of hemoglobin. Abnormal hemoglobin polymerizes when deoxygenated, resulting in sickle-shaped erythrocytes, which cause vascular occlusion and ischemia. Sickle cell anemia manifests in early childhood with symptoms associated with vascular occlusion and hemolytic anemia. Infarctions in the spleen, kidneys, bone, CNS, and other organs are common and cause progressive loss of organ function and acute and chronic pain in affected parts of the body. Acute, painful vaso-occlusive crises are provoked by conditions associated with reduced oxygen tension. Neonatal screening for sickle cell anemia has been implemented across the U.S., allowing the diagnosis to be made before the first manifestation of the disease. In older children and adults, hemoglobin quantification tests are used to diagnose the condition. The cornerstones of treatment involve the management of painful vaso-occlusive crises, hemolytic anemia, and disease complications as well as prevention of infection. Allogeneic bone marrow transplantation is the only curative treatment option.

See also acute chest syndrome.

Epidemiological data refers to the US, unless otherwise specified.


Hemoglobin composition in sickle cell disease

For details on hemoglobin and its variants, see “Hemoglobin synthesis” and “Hemoglobin variants” in the article “Erythrocyte morphology and hemoglobin.”

Hemoglobin Normal Sickle cell trait Sickle cell disease
HbA 95–98% 60% 0%
HbS 0% 40% 75–95%
HbF < 2% < 2% 5–25%


Sickle cell trait

Sickle cell disease


Hemoglobin Globin chains Sickle cells Hemoglobin C
Sickle cell trait Sickle cell disease Hemoglobin SC disease (HbSC) HbC carrier HbC disease
HbA ααββ Absent Absent Absent
HbA2 ααδδ Absent Absent
HbF ααγγ Normal Normal Normal Absent
HbH ββββ Absent Absent Absent Absent Absent
Hb Bart γγγγ Absent Absent Absent Absent Absent
HbS ααββ ↑↑ Absent Absent
HbC ααββ Absent Absent ↑↑

Disease monitoring

Long term management

Prevent infections

Prevent vaso-occlusive crises and manage anemia

Management of acute sickle cell crisis

Curative therapy

Organ damage

Recurrent vascular occlusion and disseminated infarctions lead to progressive organ damage and loss of function. In homozygotes, this progress is associated with high morbidity and mortality. In heterozygotes, organ damage is very rare.

Organ system Complications
Male genitals


As a result of repeated infarction of the spleen in sickle cell patients, the spleen is often atrophied rather than enlarged!

We list the most important complications. The selection is not exhaustive.

Sickle cell disease in pregnancy [5]

Interested in the newest medical research, distilled down to just one minute? Sign up for the One-Minute Telegram in “Tips and links” below.

  1. Schultz CL, Tchume-Johnson T, Jackson T, Enninful-Eghan H, Schapira MM, Smith-Whitley K. Reproductive intentions in mothers of young children with sickle cell disease.. Pediatr Blood Cancer. 2020; 67 (5): p.e28227. doi: 10.1002/pbc.28227 . | Open in Read by QxMD
  2. Al Jama FE, Gasem T, Burshaid S, Rahman J, Al Suleiman SA, Rahman MS. Pregnancy outcome in patients with homozygous sickle cell disease in a university hospital, Eastern Saudi Arabia. Arch Gynecol Obstet. 2009; 280 (5): p.793-797. doi: 10.1007/s00404-009-1002-7 . | Open in Read by QxMD
  3. Boafor TK, Olayemi E, Galadanci N, et al. Pregnancy outcomes in women with sickle-cell disease in low and high income countries: a systematic review and meta-analysis.. BJOG. 2016; 123 (5): p.691-8. doi: 10.1111/1471-0528.13786 . | Open in Read by QxMD
  4. Gong L, Parikh S, Rosenthal PJ, Greenhouse B. Biochemical and immunological mechanisms by which sickle cell trait protects against malaria. Malar J. 2013; 12 (1): p.317. doi: 10.1186/1475-2875-12-317 . | Open in Read by QxMD
  5. Modell B, Darlison M. Global epidemiology of haemoglobin disorders and derived service indicators. Bull World Health Organ. 2008; 86 (6): p.480-487.
  6. Salyer SW. Hematologic Emergencies. Elsevier ; 2007 : p. 555-574
  7. Hernigou P, Daltro G, Flouzat-Lachaniette CH, Roussignol X, Poignard A. Septic arthritis in adults with sickle cell disease often is associated with osteomyelitis or osteonecrosis.. Clin Orthop Relat Res. 2010; 468 (6): p.1676-81. doi: 10.1007/s11999-009-1149-3 . | Open in Read by QxMD
  8. Banerjee S. Sickle cell hepatopathy. Hepatology. 2001; 33 (5): p.1021-1028. doi: 10.1053/jhep.2001.24114 . | Open in Read by QxMD
  9. Longo D, Fauci A, Kasper D, Hauser S, Jameson J, Loscalzo J. Harrisons's Principles of Internal Medicine, 18th Edition, 2011. McGraw-Hill Medical ; 2011
  10. Yawn et al. Management of sickle cell disease: summary of the 2014 evidence-based report by expert panel members.. JAMA. 2014; 312 (10): p.1033-48. doi: 10.1001/jama.2014.10517 . | Open in Read by QxMD
  11. Evidence-Based Management of Sickle Cell Disease: Expert Panel Report, 2014. Updated: September 1, 2014. Accessed: November 27, 2019.
  12. Al-Salem A. The Acute Chest Syndrome in Sickle Cell Anemia. Springer ; 2015
  13. Acute Chest Syndrome. Updated: January 1, 2019. Accessed: November 27, 2019.
  14. Howard J, Hart N, Roberts-Harewood M, et al. Guideline on the management of acute chest syndrome in sickle cell disease. Br J Haematol. 2015; 169 (4): p.492-505. doi: 10.1111/bjh.13348 . | Open in Read by QxMD
  15. Ballas SK, Lieff S, Benjamin LJ, et al. Definitions of the phenotypic manifestations of sickle cell disease. Am J Hematol. 2009 : p.NA-NA. doi: 10.1002/ajh.21550 . | Open in Read by QxMD
  16. Chaturvedi S, Ghafuri DL, Glassberg J, Kassim AA, Rodeghier M, DeBaun MR. Rapidly progressive acute chest syndrome in individuals with sickle cell anemia: a distinct acute chest syndrome phenotype. Am J Hematol. 2016; 91 (12): p.1185-1190. doi: 10.1002/ajh.24539 . | Open in Read by QxMD
  17. The management of sickle cell disease. Updated: January 1, 2002. Accessed: February 26, 2020.
  18. Dessap AM, Deux J-F, Abidi N, et al. Pulmonary Artery Thrombosis during Acute Chest Syndrome in Sickle Cell Disease. Am J Respir Crit Care Med. 2011; 184 (9): p.1022-1029. doi: 10.1164/rccm.201105-0783oc . | Open in Read by QxMD
  19. Vichinsky EP, Neumayr LD, Earles AN, et al. Causes and Outcomes of the Acute Chest Syndrome in Sickle Cell Disease. N Engl J Med. 2000; 342 (25): p.1855-1865. doi: 10.1056/nejm200006223422502 . | Open in Read by QxMD
  20. Otrock ZK, Thibodeaux SR, Jackups R. Vascular access for red blood cell exchange. Transfusion. 2018; 58 (S1): p.569-579. doi: 10.1111/trf.14495 . | Open in Read by QxMD
  21. Okomo U, Meremikwu MM. Fluid replacement therapy for acute episodes of pain in people with sickle cell disease. Cochrane Database of Systematic Reviews. 2017 . doi: 10.1002/14651858.cd005406.pub5 . | Open in Read by QxMD

3 free articles remaining

You have 3 free member-only articles left this month. Sign up and get unlimited access.
 Evidence-based content, created and peer-reviewed by physicians. Read the disclaimer