Plagiocephaly & Craniosynostosis

A neonate’s head shape can be distorted from in-utero positional deformation or birth trauma; it should spontaneously resolve by 8 weeks. If an abnormal head shape persists, consider both deformational plagiocephaly (common, benign) and craniosynostosis (uncommon, needs timely surgical referral). See also 6-week check and congenital muscular torticollis (a common contributor to plagiocephaly).

Comparison

	Deformational plagiocephaly	Craniosynostosis
Cause	External pressure (back sleeping, restricted intrauterine environment, muscular torticollis, prematurity)	Premature fusion of one or more cranial sutures
Onset	Not usually present at birth; usually noted after ~3 months	Present at birth
Risk factors	Developmental delay (e.g. hypotonia), torticollis, hip spica cast, supine sleeping	Family history in some cases
Incidence	Most common cause of abnormal head shape — affects ~1 in 5 infants	1 in 2,000–2,500 live births
Diagnosis	Clinical examination	Clinical examination; imaging in select cases
Head shape	Parallelogram	Rhomboid (varies by suture involved)
Ear displacement	Present, anteriorly	Present, toward the affected suture
Frontal bossing	Ipsilateral	Contralateral

Non-syndromic craniosynostosis occurs without extracranial dysmorphism, most often involving a single suture (commonly sagittal). Syndromic craniosynostosis (9.9–18.3% of cases) involves multiple sutures with extracranial features — over 200 associated syndromes (Muenke, Apert, Crouzon). Unilateral lambdoid synostosis can closely mimic deformational plagiocephaly, making this the trickiest distinction.

Deformational plagiocephaly

History: occurs with prolonged same-position lying (classically supine sleeping); often associated with torticollis (restricted neck movement — young babies without head control are more susceptible. Torticollis-associated flattening occurs on the opposite side to the neck stiffness.

Examination — inspect the skull from 3 views (child sitting on a parent’s lap, facing the parent):

• From above — forehead shape, skull length/width, ear position, frontal bone/occipital symmetry.
• From behind — skull base/ear level, mastoid bulging.
• From the front — facial symmetry.

The occiput is almost always involved in positional plagiocephaly (a severity assessment tool is available via HealthPathways). Check the ear on the flattened side — pushed anteriorly when viewed from above, though both ears should be level viewed from the front. Look for forehead/ear/ cheek bulging on the flattened side, and reduced hair growth over the flattened area. If there’s no torticollis, the baby will have full neck rotation and lateral flexion — check this specifically by having the child turn to look each way. Track sequential head circumference on growth charts — crossing centiles is more informative than a single measurement.

Investigations: none required for straightforward positional plagiocephaly.

Management — conservative, aims to improve shape as the skull grows:

• Alternate head position during sleep; alternate which end of the cot the baby lies at.
• Supervised tummy time; interact face-to-face during play.
• Vary holding/carrying positions; if bottle-feeding, alternate the arm the baby lies in.
• Turn the pram to face forward (encourages active head-turning); use a low-back highchair and reposition it to encourage turning.
• Carry/sit the baby out of the pram/capsule to relieve pressure.
• Refer to paediatric physiotherapy if torticollis is present — for stretches, positioning advice, and to monitor neck range of motion.
• Pillows in the cot are not recommended — not SIDS-safe.

Inform parents: final appearance depends on the original severity; once the infant sits independently, plagiocephaly is unlikely to worsen.

Helmet therapy (moulding helmet, typically age 4–8 months) may be tried for severe, non-responsive cases via a specific helmet service — but the evidence for benefit remains contentious and is not universally accepted. The HEADS randomised controlled trial found no clear benefit over natural resolution/repositioning for most infants, and a 2024 systematic review found the evidence base still not fully validated (mostly low-quality retrospective studies). It may still have a role in severe cases with early initiation and high compliance, but should not be presented to parents as reliably superior to conservative repositioning.

Craniosynostosis

Premature fusion of one or more sutures restricts skull growth perpendicular to that suture, with compensatory overgrowth in the parallel plane — producing a distinctive head shape depending on which suture(s) are involved. Progressive slowing of head growth occurs (unlike plagiocephaly).

If craniosynostosis is suspected: arrange urgent paediatric or craniofacial assessment — imaging is not required before referral. Diagnosis is usually clinical (expert assessment is sensitive, accurate and low-risk), confirmed on X-ray or other imaging as directed by the craniofacial team. Prompt referral to a paediatric craniofacial surgeon is needed for surgical planning — most single-suture cases operated at 5–10 months, and time-sensitivity is a key reason to get the distinction right early.