Frontal bossing is a medical term used to describe a prominent, protruding forehead that’s also often associated with a heavy brow ridge.
This sign is the main marker of many conditions, including issues that affect a person’s hormones, bones, or stature. A doctor typically identifies it in infancy or early childhood.
Treatments can address the condition that’s causing the frontal bossing. However, they can’t correct a protruding forehead because frontal bossing changes the way the bone and tissues of the face and skull form.
Frontal bossing causes your child to have an enlarged or protruding forehead or an enlarged eyebrow ridge. This sign may be mild in the early months and years of your child’s life, but it may become more noticeable as they age.
Frontal bossing may be a sign of a genetic disorder or congenital defect, meaning a problem that is present at birth. The cause of the bossing may also play a factor in other problems, such as physical deformities.
Frontal bossing can be due to certain conditions that affect your child’s growth hormones. It may also be seen in some types of severe anemia that cause increased, but ineffective, production of red blood cells by the bone marrow.
One common underlying cause is acromegaly. This is a chronic disorder that leads to an overproduction of growth hormone. These areas of the body are larger than normal for people with acromegaly:
- skull bones
Other potential causes of frontal bossing include:
- use of the antiseizure drug trimethadione during pregnancy
- basal cell nevus syndrome
- congenital syphilis
- cleidocranial dysostosis
- Russell-Silver syndrome
- Rubinstein-Taybi syndrome
- Pfeiffer syndrome
- Hurler syndrome
- Crouzon syndrome
- abnormal growths in the forehead or skull
- certain types of anemia, such as thalassemia major (beta-thalassemia)
Abnormalities in an infant’s PEX1, PEX13, and PEX26 genes can also cause frontal bossing.
A doctor can diagnose frontal bossing by examining your child’s forehead and brow ridge and measuring your child’s head. However, the cause of the condition may not be so clear. Since frontal bossing often signals a rare disorder, other symptoms or deformities may offer clues as to its underlying cause.
Your doctor will physically inspect your child’s forehead and take down their medical history. You should be ready to answer questions about when you first noticed the frontal bossing and any other unusual characteristics or symptoms your child might have.
Your doctor may order blood tests to check your child’s hormone levels and to look for genetic abnormalities. They may also order imaging scans to help determine the cause of frontal bossing. Imaging scans commonly used for this purpose include X-rays and MRI scans.
An X-ray can reveal deformities in the skull that may be causing the forehead or brow region to protrude. A more detailed MRI scan can show abnormalities in the surrounding bones and tissues.
Abnormal growths may be causing the forehead protrusion. Imaging scans are the only way to rule out this potential cause.
There’s no treatment to reverse frontal bossing. Management focuses on treating the underlying condition or at least lessening the symptoms. Frontal bossing doesn’t usually improve with age. However, it doesn’t worsen in most cases.
Cosmetic surgery can be helpful in treating many facial deformities. However, there are no current guidelines recommending cosmetic surgery to improve the appearance of frontal bossing.
There are no known ways to prevent your child from developing frontal bossing. However, genetic counseling may help you determine if your child is likely to be born with one of the rare conditions that cause this symptom.
Genetic counseling may include blood and urine tests for both parents. If you’re a known carrier of a genetic disease, your doctor may recommend certain fertility medications or treatments. Your doctor will discuss which treatment option is right for you.
Always avoid the antiseizure medication trimethadione during pregnancy to reduce the risk of your child being born with frontal bossing.