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Bulging Fontanels

A fontanel is more commonly known as a soft spot. When a baby is born, they typically have several fontanels where bones of their skull haven’t fused yet. A newborn has fontanels on the top, back, and sides of their head. Usually, only the anterior fontanel, which is on the top of the head towards the front, can be seen and felt. This is the one called the soft spot. In some babies, the posterior fontanel, which is found toward the back of the head, can also be felt, though it’s much smaller.

It’s important for new parents to understand what a fontanel looks and feels like. A baby’s soft spot should feel relatively soft and curve inward very slightly.

Changes in texture or appearance can be a sign of serious health issues. Parents should watch for soft spots that are curved outward on their baby’s head and feel firm. This is known as a bulging fontanel and may be a sign of brain swelling or fluid buildup in the brain. These can cause pressure inside the skull to rise and may result in damage to the baby’s developing brain.

A bulging fontanel is an emergency. If your child is experiencing this symptom, seek medical attention immediately.

What Can Happen If a Bulging Fontanel Is Not Treated?

A bulging soft spot can be a sign of several very serious conditions. The consequences of not seeking treatment right away can be dire. For instance, encephalitis, a common cause of bulging fontanels, can lead to permanent brain damage or even death in severe cases.

What Are the Causes of a Bulging Fontanel?

Common Causes

Some of the most common causes of a bulging fontanel are:

  • encephalitis, which is a brain inflammation caused by a viral or bacterial infection
  • hydrocephalus, which is excess brain fluid that’s present at birth or occurs from injury or infection
  • meningitis, which is inflammation of the brain and spinal cord tissue that results from a viral or bacterial infection
  • hypoxic-ischemic encephalopathy, which is brain swelling and damage that occurs when your baby’s brain is deprived of oxygen for a long period
  • intracranial hemorrhaging, or bleeding in the brain
  • head trauma

Other Causes

A 2003 article in American Family Physician identifies the following additional conditions, along with numerous others, as possible causes:

  • a brain tumor or abscess
  • Lyme disease, which is a bacterial infection you get from an infected tick
  • Addison’s disease, which is a condition in which your adrenal glands don’t make enough hormones for your body to function properly
  • congestive heart failure, which occurs when blood and fluid buildup in parts of your body because your heart can’t pump enough blood
  • leukemia, or cancer of the white blood cells
  • an electrolyte disturbance, which is when your blood’s levels of certain chemicals, such as sodium and potassium, are out of balance
  • hyperthyroidism, which is when your thyroid makes more hormones than you need
  • maple syrup urine disease, which occurs when your body can’t properly break down proteins
  • anemia, which is a condition in which your blood doesn’t contain enough oxygen

When Should I Seek Medical Care?

There are several factors that can make a soft spot appear to be bulging when in reality there’s no danger. Common things babies do such as lying down, vomiting, or crying can be mistaken for your baby having a bulging fontanel.

To determine whether your infant actually has a bulging fontanel, first try to calm them down, and then position them so their head is upright. If you succeed in doing this and the soft spot still appears to be bulging, seek medical attention for your child immediately.

Don’t wait to make a doctor’s appointment, go to the nearest emergency room. This is especially crucial if your baby has a fever or seems extremely sleepy.

What to Expect at the Hospital

Because there can be many explanations for these symptoms, your doctor will collect as much information as possible about your child’s condition.

Your doctor will perform a physical examination of your infant and will likely ask:

  • which soft spots appear to be bulging
  • whether the bulge is constant or appears normal at times
  • when you first noticed the abnormal appearance of the soft spot

Be sure to tell your doctor about any other symptoms you’ve observed, including marked drowsiness, an elevated temperature, or irritability beyond what’s normal for your child.

Depending on the answers you provide and other symptoms that may be present, your doctor may order one or more tests, such as an MRI or CT scan, to make a diagnosis.

Lumbar puncture, or a spinal tap, may also be performed. This involves taking a sample of cerebrospinal fluid from your baby’s lower spine to check for disease and infection in their nervous system.

Treatment will depend on the underlying cause of your baby’s symptoms.

Is There Any Way to Prevent a Bulging Fontanel?

There’s no definite way to prevent fontanels from bulging. This is in large part because the symptom has so many potential causes.

However, it’s important that parents and other caregivers avoid unnecessary hospital visits by learning how to distinguish between a soft spot that temporarily appears to be bulging and one that’s actually protruding.

Content licensed from:

Written by: Krista O'Connell
Medically reviewed on: Feb 22, 2016: Karen Richardson Gill, MD, FAAP

This feature is for informational purposes only and should not be used to replace the care and information received from your health care provider. Please consult a health care professional with any health concerns you may have.
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