Harlequin sign is a benign, transient erythematous color change affecting one longitudinal half of the body, most commonly observed in low-birth-weight or premature infants. The reddening typically appears when the infant is positioned on one side and resolves upon repositioning or supine placement.

Pathophysiology

• The sign reflects immature autonomic vascular regulation in neonates.

• Sympathetic nervous system immaturity causes asymmetric vasodilation, leading to reddening on the dependent side and relative pallor on the contralateral side.

• Usually occurs in premature or low-birth-weight infants, but can occasionally appear in term infants.

• No structural or systemic pathology is involved; the phenomenon is self-limited.

Examination Technique

1. Patient positioning: Observe the infant when placed on either lateral side.

2. Observation: Note any distinct erythema on one longitudinal half of the body with a sharp midline demarcation.

3. Repositioning: Place the infant in the supine position to see if the redness resolves.

4. Duration: Typically disappears immediately but may persist up to 20 minutes.

5. Documentation: Record the affected side, duration, and recurrence.

Clinical Features

Differential Diagnosis

Pediatric considerations

• Essential to recognize as benign to prevent unnecessary interventions.

• Parents may be reassured about the transient, harmless nature of the phenomenon.

• Occurrence is more frequent in premature infants due to immature autonomic vascular control.

Limitations

• Observation depends on proper positioning of the infant.

• Misinterpretation as a pathological rash may lead to unnecessary investigations.

Patient/Parent counseling

• Explain that the color change is normal, transient, and not harmful.

• Reassure parents that it resolves with repositioning.

• Advise monitoring for other signs of illness, such as fever, lethargy, or poor feeding, which are unrelated to the Harlequin sign.

Conclusion

Harlequin sign is a benign, transient, position-dependent erythema in neonates, primarily seen in premature or low-birth-weight infants. Recognition prevents unnecessary worry or interventions, and the sign usually resolves spontaneously without treatment.

References

1. Maisels MJ, McDonagh AF. Neonatal jaundice: Clinical assessment and management. Pediatr Clin North Am. 2008;55(4):923–946.

2. Burgos AE, et al. Harlequin color change in neonates. Am J Dis Child. 1981;135(7):637–639.

3. Stoll BJ, et al. Neonatal Disorders. 10th ed. Philadelphia: Elsevier; 2020.

4. Eichenwald EC, Stark AR. Manual of Neonatal Care. 8th ed. Philadelphia: Lippincott Williams & Wilkins; 2020.