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Etiology and evaluation of cyanosis in children

Anne M Stack, MD
Section Editor
Stephen J Teach, MD, MPH
Deputy Editor
James F Wiley, II, MD, MPH


This topic will discuss the differential diagnosis and approach to the child with cyanosis.


Cyanosis, a bluish purple discoloration of the tissues due to an increased concentration of deoxygenated hemoglobin in the capillary bed, results from a variety of conditions, many of which are life-threatening [1]. It is most easily appreciated in the lips, nail beds, earlobes, mucous membranes, and locations where the skin is thin. It may be enhanced or obscured by lighting conditions and skin pigmentation. In children, life-threatening cyanosis most often results from respiratory disorders.


Two mechanisms result in cyanosis: systemic arterial oxygen desaturation and increased oxygen extraction by the tissues. Based upon these mechanisms, two types of cyanosis are described: central and peripheral. In addition, dermatologic conditions may result in blue skin color that mimics cyanosis in the absence of increased levels of deoxygenated blood in the capillary beds. (See 'Dermatologic conditions' below.)

Central cyanosis — Central cyanosis is evident when systemic arterial concentration of deoxygenated hemoglobin (Hb) in the blood exceeds 5 gm/dL (3.1 mmol/L) (oxygen saturation ≤85 percent) [2]. Of note, cyanosis cannot be detected by observation in patients with severe anemia (Hb <5 gm/dL [3.1 mmol/L]).

Peripheral cyanosis — Patients with peripheral cyanosis have a normal systemic arterial oxygen saturation. However, increased oxygen extraction results in a wide systemic arteriovenous oxygen difference and increased deoxygenated blood on the venous side of the capillary beds. The increased extraction of oxygen results from sluggish movement of blood through the capillary circulation. Causes include vasomotor instability, vasoconstriction caused by exposure to cold, venous obstruction, elevated venous pressure, polycythemia, and low cardiac output.

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Literature review current through: Nov 2017. | This topic last updated: Dec 16, 2015.
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  1. Driscoll DJ. Evaluation of the cyanotic newborn. Pediatr Clin North Am 1990; 37:1.
  2. Grant JB, Saltzman AR. Respiratory functions of the lung. In: Textbook of Pulmonary Diseases, 5th, Baum GL, Wolinsky E (Eds), Little, Brown, Boston 1994.
  3. DiMaio AM, Singh J. The infant with cyanosis in the emergency room. Pediatr Clin North Am 1992; 39:987.
  4. West JB. Pulmonary gas exchange. In: Physiological Basis of Medical Practice, 12th, West JB (Ed), Williams & Wilkins, Baltimore 1990. p.546.
  5. Woods WA, McCulloch MA. Cardiovascular emergencies in the pediatric patient. Emerg Med Clin North Am 2005; 23:1233.
  6. Berger S, Konduri GG. Pulmonary hypertension in children: the twenty-first century. Pediatr Clin North Am 2006; 53:961.
  7. Sasidharan P. An approach to diagnosis and management of cyanosis and tachypnea in term infants. Pediatr Clin North Am 2004; 51:999.
  8. Cooke JP, Marshall JM. Mechanisms of Raynaud's disease. Vasc Med 2005; 10:293.
  9. Conlon JD, Drolet BA. Skin lesions in the neonate. Pediatr Clin North Am 2004; 51:863.
  10. Dereure O. Drug-induced skin pigmentation. Epidemiology, diagnosis and treatment. Am J Clin Dermatol 2001; 2:253.
  11. Sweeney SM. Tattoos: a review of tattoo practices and potential treatment options for removal. Curr Opin Pediatr 2006; 18:391.
  12. Fung MC, Bowen DL. Silver products for medical indications: risk-benefit assessment. J Toxicol Clin Toxicol 1996; 34:119.
  13. Dahshan A, Donovan GK. Severe methemoglobinemia complicating topical benzocaine use during endoscopy in a toddler: a case report and review of the literature. Pediatrics 2006; 117:e806.
  14. Wright RO, Lewander WJ, Woolf AD. Methemoglobinemia: etiology, pharmacology, and clinical management. Ann Emerg Med 1999; 34:646.
  15. Stack AM. Cyanosis. In: Textbook of Pediatric Emergency Medicine, 5th, Fleisher GR, Ludwig S, Henretig FM (Eds), Lippincott Willaims & Wilkins, Philadelphia 2006. p.223.