• congenital disorder which is the most common cause of stridor in infancy
• larynx appears disproportionately small, and supporting structures are abnormally soft
• stridor begins within the first 4 weeks of life, and accentuates with increased ventilation (crying, excitement, URI, etc.)
• stridor usually resolves by 12 months but may recur with URI until about 3 years of age
• diagnosis is by fiberoptic bronchoscopy or direct laryngoscopy
• therapy is usually not needed, but rarely laser therapy of redundant tissue or traceostomy when stridor occurs with failure to thrive or apnea

References

NMS Pediatrics, 4th edition