Description

A 6-day-old newborn girl from an unremarkable pregnancy and vaginal delivery was observed for the first time by her primary care physician presenting facial asymmetry when crying. Physical and neurological examination showed facial asymmetry noted only on crying, with a drooping of the right corner of the mouth (figure 1). The eyelid closure, nasolabial fold depths, forehead elevation and tearing, were symmetric and normal. The facial asymmetry disappeared after the crying stopped (figure 2) and, according to the mother, this was happening since birth.

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Figure 1

When crying, the right lower lip is pulled downward. The left affected side maintains its position.

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Figure 2

At rest, the face appears symmetric.

Asymmetric crying facies (ACF) is characterised by lower lip asymmetry in neonates only during crying.1 ACF has an incidence of 1:160 live births.1 It can result from a developmental abnormality caused by absence (agenesis) or incomplete development (hypoplasia) of the depressor muscle of the angle of the mouth or of the depressor muscle of the lower lip; likewise, it can result from a traumatic compression of the facial nerve in utero or during labour.1 ,2

ACF, considered a minor anomaly, however, causes severe parental distress. If misdiagnosed it can lead to unnecessary work up and even inappropriate treatments.2 ,3 ACF should be differentiated from other facial asymmetries, namely facial palsy, and the differential diagnosis is purely clinical.1

In the case reported, since no complications were described during delivery, congenital ACF was suspected. It has been associated with other congenital abnormalities such as of cardiovascular, genitourinary, respiratory and musculoskeletal origin.3 Our patient had no suspicion of coexisting anomalies and was therefore kept under clinical surveillance.