SymptomChildren's health
Smooth Philtrum
A smooth philtrum is a flattened groove between the nose and upper lip, where the two vertical ridges are faint or absent. On its own it can be a normal family trait. Combined with a thin upper lip and short eye openings, it is one of the three classic facial features of fetal alcohol syndrome, caused by alcohol exposure before birth. It also occurs in some genetic conditions. Doctors grade it with a standard lip-philtrum guide as part of a wider developmental assessment.
Also called: Flat philtrum, indistinct philtrum, long smooth philtrum
At a glance
- What it is
- A flat or shallow groove between the nose and upper lip, with poorly defined ridges.
- Most important link
- Fetal alcohol syndrome, together with a thin upper lip and short eye openings.
- Other causes
- Normal family variation, and genetic syndromes such as Williams, 22q11.2 deletion and Cornelia de Lange syndromes.
- How it is assessed
- Compared with a 5-point lip-philtrum photo guide, as part of a full developmental and growth exam.
- Treatment
- The feature itself needs none. Support targets any developmental, learning or health needs.
When to get help
Book a routine appointment
- A child with a smooth philtrum and a thin upper lip, especially with small head size, poor growth or developmental delay
- Any concern about a child's learning, attention, behavior or development, with known or possible alcohol exposure in pregnancy
- A baby with unusual facial features plus feeding problems, heart murmur or low muscle tone
Usually safe to manage at home
- A smooth philtrum in an adult or child with normal development, where other family members have the same feature
What the philtrum is
The philtrum is the vertical groove in the middle of the upper lip, running from the base of the nose to the lip edge. It is bordered by two ridges called philtral columns. It forms between about weeks 6 and 9 of pregnancy as the tissues of the face fuse.
A smooth philtrum has shallow or absent ridges and a flat groove. Doctors also note its length: a long philtrum is a separate feature that occurs in several genetic syndromes.
Philtrum shape varies naturally, and some people simply have a flat philtrum, like their parents. The feature only matters medically when it appears with other signs.
Smooth philtrum and fetal alcohol syndrome
Alcohol crossing the placenta in early pregnancy disrupts the development of the midface. Fetal alcohol syndrome (FAS), the most recognizable form of fetal alcohol spectrum disorder (FASD), is diagnosed with three facial features:
- a smooth philtrum
- a thin upper lip (thin vermilion border)
- short eye openings (short palpebral fissures)
Plus:
- growth below the 10th percentile for height or weight
- signs of brain involvement, such as a small head size, seizures or neurodevelopmental problems
- in some criteria, confirmed or suspected prenatal alcohol exposure
Most people with FASD do not have the full facial features. These appear only when heavy drinking occurred during the narrow window of facial development. Learning, attention, memory, behavior and social difficulties can occur without any facial signs. No amount of alcohol in pregnancy is known to be safe.
How common is FASD?
Estimates suggest FASD may affect a few percent of school-aged children in the US, though many are undiagnosed. Full FAS is less common.
Other conditions with a smooth or long philtrum
| Condition | Other typical features |
|---|---|
| Williams syndrome | Long philtrum, full lips, star-like iris pattern, heart narrowing, very sociable personality |
| 22q11.2 deletion syndrome | Heart defects, cleft palate, low calcium, frequent infections |
| Cornelia de Lange syndrome | Long smooth philtrum, joined eyebrows, small hands, growth delay |
| Toluene embryopathy and some anticonvulsant exposures | Similar facial changes to FAS |
| Other chromosomal conditions | Varied features found on genetic testing |
How doctors assess it
A pediatrician, developmental specialist or geneticist will:
- Look at the face straight on and in profile, with the child relaxed and not smiling. The philtrum and upper lip are compared with the University of Washington lip-philtrum guide, a 5-point photographic scale. Scores of 4 or 5 indicate a smooth philtrum and thin lip.
- Measure the eye openings and head circumference and compare them with charts for age and ethnicity.
- Plot growth on standard charts.
- Take a careful history, including alcohol and other exposures during pregnancy, ideally in a non-judgmental way.
- Assess development with standardized tests of learning, language, motor skills, attention and behavior.
- Arrange genetic testing, such as a chromosomal microarray, when features suggest a genetic syndrome or alcohol exposure is unknown.
Facial features change with age. They are usually clearest between about 2 and 10 years, so assessment in babies and adults can be more difficult.
Treatment and support
A smooth philtrum needs no treatment. What matters is support for any underlying condition:
- Early intervention: speech, occupational and physical therapy for young children
- Educational support: individualized education plans at school
- Behavioral and parent training: structured routines and strategies that suit children with FASD
- Medical care: treatment of attention problems, sleep difficulties, seizures and any heart, hearing or vision problems
- Genetic counseling for families when a genetic syndrome is diagnosed
Early diagnosis, ideally before age 6, and a stable, supportive home are linked to better long-term outcomes in FASD.
Prevention
FAS is completely preventable. Avoiding alcohol throughout pregnancy, and when trying to conceive, eliminates the risk. Women who drank before realizing they were pregnant should stop and discuss it with their doctor, without fear of judgment.
Frequently asked questions
What does a smooth philtrum mean?
It means the groove between your nose and upper lip is flat, with faint or absent ridges. By itself it is often a normal family trait. With a thin upper lip and short eye openings, it suggests fetal alcohol syndrome, and it can also occur in some genetic syndromes.
Is a smooth philtrum always a sign of fetal alcohol syndrome?
No. Many people with a smooth philtrum have no medical condition. Fetal alcohol syndrome is considered only when it appears with other features, such as a thin upper lip, short eye openings, small head size, growth problems or developmental difficulties.
Can adults have a smooth philtrum?
Yes. Some adults have a naturally flat philtrum. In adults with FASD, facial features often become less obvious with age, so diagnosis relies more on childhood photographs, history and neurodevelopmental assessment.
Can a smooth philtrum be fixed?
It does not need fixing, as it causes no health problems. Cosmetic lip surgery exists but is rarely sought for this reason. Support for any learning, behavior or health needs is what makes the difference for people with FASD.
How is fetal alcohol syndrome diagnosed?
It is diagnosed by a specialist using facial measurements and a lip-philtrum guide, growth charts, head size, developmental testing and a history of alcohol exposure in pregnancy. Genetic tests may be used to rule out other conditions with similar features.
Sources
This guide was written from current patient and clinical guidance, including:
- CDC: Fetal alcohol spectrum disorders (FASDs): Criteria and diagnosis
- American Academy of Pediatrics: Fetal alcohol spectrum disorders toolkit
- University of Washington FAS Diagnostic and Prevention Network: Lip-philtrum guide
- NHS: Foetal alcohol spectrum disorder
- National Institute on Alcohol Abuse and Alcoholism (NIAAA): Fetal alcohol exposure