Congenital unilateral lower lip palsy (CULLP)

What is congenital unilateral lower lip palsy (CULLP)?

Congenital unilateral lower lip palsy (CULLP) is a condition that is present at birth that causes one side of the baby’s face to remain still when he or she cries. When a baby cries, the mouth is pulled downward on only one side of the face while the other half of the mouth does not move. When the baby’s mouth is relaxed, the face appears to be symmetric (even).

Risk factors

CULLP occurs in one out of 160 live births (source - Facial Palsy). Babies born with CULLP are at an increased risk for developing other conditions, such as those affecting the cardiovascular (heart) system, neck and face, or the urinary system.

What are the signs and symptoms of congenital unilateral lower lip palsy (CULLP)?

• Both nostrils expand equally when baby breathes (shows that palsy only affects the lower lip)
• Eyes close normally on both sides of the face (shows that palsy only affects the lower lip)
• Mouth pulls downward on only one side when baby cries
• Slight thinning of the lip on the affected side
• Sucking is normal, with no increased drooling

What are the causes of congenital unilateral lower lip palsy (CULLP)?

CULLP is typically caused by:

• Compression of the facial nerve due to birth trauma
• Problems during fetal development, such as underdevelopment of the muscles of the lips