How should I manage a flat spot (positional plagiocephaly) on a baby under 6 months old that developed while sleeping?

Management of Flat Spot on Baby's Skull (Positional Plagiocephaly)

For a baby under 6 months with a flat spot on the skull, start immediately with repositioning education—varying head position during sleep, implementing daily supervised awake tummy time, and holding the baby upright when awake—and escalate to physical therapy if the deformity is moderate or fails to improve with repositioning alone. 1

Understanding the Condition

Positional plagiocephaly has dramatically increased since the "Back to Sleep" campaign began in 1992, but this is an acceptable trade-off because back-sleeping must continue for all infants to prevent SIDS, as the mortality benefits vastly outweigh the cosmetic concerns of skull flattening. 2, 1 The condition presents as unilateral flattening of the back-side of the head with a rhomboid-like shift, forward displacement of the ear on the same side, and bulging of the forehead on that side. 1

Reassure parents that positional plagiocephaly has no consequences on brain development and improves dramatically over time—incidence decreases spontaneously from 20% at 8 months to just 3% at 24 months in healthy children. 2, 1

Diagnosis

• Clinical examination by an experienced provider is sufficient for diagnosis; imaging is rarely necessary. 1
• The critical task is ruling out craniosynostosis (premature fusion of skull bones), which requires surgical intervention rather than conservative management. 1
• If clinical examination is unclear, three-dimensional surface imaging or stereophotogrammetry can be used for assessment. 3

Treatment Algorithm by Severity

Mild Cases (First-Line for All Infants Under 6 Months)

Start with repositioning education immediately: 1

• Vary the baby's head position during sleep—alternate which direction the head faces each night to avoid constant pressure on one spot. 1
• Implement daily supervised awake tummy time starting as early as possible—this promotes motor development, strengthens upper body muscles, and minimizes plagiocephaly risk. 2, 4
• Hold the baby upright when not sleeping to reduce time spent with head against flat surfaces. 2, 1
• Never use soft positioning devices or pillows in the sleeping environment—the American Academy of Pediatrics explicitly warns against these as they increase SIDS risk and contradict safe sleep guidelines. 2, 1

Moderate Cases or Failed Repositioning

Physical therapy is superior to repositioning alone based on Class I randomized controlled trial evidence and should be the preferred intervention. 2, 1 One randomized trial demonstrated that repositioning education was inferior to a structured physical therapy intervention program. 2

Physical therapy is particularly effective when there is associated neck muscle tightness (congenital muscular torticollis), which commonly accompanies positional plagiocephaly. 5, 6

Severe or Refractory Cases

Helmet therapy corrects asymmetry more rapidly and to a greater degree than repositioning education. 2, 1 The Congress of Neurological Surgeons systematic review found that five of seven cohort studies comparing repositioning with helmet therapy reported helmets to be better and take less time. 2

• Helmet therapy typically requires 3 months of treatment. 1, 7
• Success rates for acceptable cranial shape may be as high as 92% with appropriate treatment. 5
• Helmet therapy is most effective when initiated before 6 months of age, as the skull becomes less malleable after this period. 7, 5

Critical Safety Considerations

Continue back-sleeping for all sleep periods regardless of plagiocephaly concerns—once an infant can roll from supine to prone and back independently (typically 4-6 months), they can be allowed to remain in whatever position they assume, but should still be placed on their back initially. 2

Tummy time must always be supervised and occur only when the infant is awake—this is completely distinct from sleep positioning and should never be used as a sleep position. 4

Common Pitfalls to Avoid

• Starting intervention too late—the deformity typically worsens during the first 6 months when the skull is most susceptible to constant pressure. 7
• Relying solely on repositioning for moderate cases when physical therapy has proven superior efficacy. 2, 1
• Using soft positioning devices or pillows, which increase SIDS risk. 2, 1
• Failing to distinguish positional plagiocephaly from craniosynostosis, which requires surgical intervention. 1, 3