Baby Sunken Fontanelles: Reasons, Diagnosis,Treatment & Prevention

Baby Sunken Fontanelles – Causes, Treatments & Prevention

The human skull is made up of several bones and various tissues. In newborns, the bones are not completely connected at the top, back, and sides of the head, and the fragments are connected by tissues. These spots on the head are called soft spots, and they provide flexibility to the baby’s head so that it can pass through the birth canal. These soft spots get covered up by bones as the baby grows older, thus it is always said that the baby’s head is delicate and should be handled with utmost care. There are some spots that need to be taken care of more than the others, for the baby’s health and safety.

What Is a Sunken Fontanelle?

The several soft spots on a baby’s head are known as fontanelles. Two main fontanelles on the skull are those on the back side and on the front side. These soft spots provide flexibility to the skull so that the baby’s head can pass easily through the birth canal. During the baby’s first year of growth, the fontanelles provide space for the brain to grow and develop as required.

These soft spots or fontanelles are generally curved slightly inward. While it is common to see the soft spot slightly curved, a noticeable inward curve can be a matter of serious concern. In medical terms, this is known as a sunken fontanelle. A very sunken soft spot on the top of the head can be dangerous, and needs immediate medical attention.

What Does It Look Like?

The soft spots or fontanelles can be of two types:

Bulging Fontanelle: The soft spot might be bulging a bit outwards, or you might feel a bump at the soft spot. It’s temporary when it disappears after a while, and if the baby cries about it (the head may have been bumped). However, if it does not return to a flat position, it is be a matter of concern.

Sunken Fontanelle: When the fontanelle is touched, it should be firm, yet with a slight inward curve. When there is a noticeable sink in the head at the soft spot, it can be signs of a sunken soft spot or sunken fontanelle. The sunken fontanelle is related to the health of the child.

Causes of a Sunken Fontanelle on a Baby’s Head

There are many causes of a sunken fontanelle, such as:

1. Dehydration

Dehydration occurs when the body is losing more fluid than it is receiving or retaining. A baby is said to be dehydrated when he does not have sufficient fluid in the body to maintain normal functions. Dehydration can happen due to:

  • Frequent urination and not hydrating after
  • Vomiting
  • Mild to heavy diarrhea
  • Excessive sweating
  • Not drinking enough fluids

Dehydration in a baby’s body can result in a sunken fontanelle.

2. Kwashiorkor Disease

Kwashiorkor a disease that is commonly seen in children, and is the result of a severe deficiency of protein. It happens when there is insufficient protein intake through diet. The low amounts of protein can result in a sunken fontanelle.

3. Diabetes Insipidus

Diabetes insipidus is not actually a form of diabetes – it is a rare condition in which the kidneys cannot conserve water. This results in urinating more frequently than normal, and can lead to dehydration and eventually a sunken fontanelle.

4. Insufficient Growth

The growth of a child is mainly dependent on nutrition intake. When a child is undernourished due to insufficient intake of calories, or the body’s inability to process the calories, the body fails to thrive. When a child’s body cannot meet the normal growth standards, the fontanelle may sink inwards or bulge outwards.

Risks and Complications

There are several risks and complications related to sunken fontanelles. While some can be minor issues like dehydration, which can be cured by providing fluids and nutrition to the body, there may be other complications that may be fatal, as they can be related to underlying diseases like:

How Is a Baby Sunken Fontanelle Diagnosed?

If the fontanelles sink inward while the baby is crying, and then return to a flat position, the situation may not be dangerous. However, when you can see the fontanelles sunk in more than usual, it can be a sign of a sunken fontanelle. For proper diagnosis, you must contact the doctor immediately.

What Are the Treatment Options for a Sunken Soft Spot?

If the baby has a sunken fontanelle, the doctor can diagnose it and its cause. Various examinations for assessing the severity of the sunken fontanelle can be done, such as:

  • A physical examination by looking, touching, and feeling the soft spots, and assessing the area’s elasticity.
  • Examinations through tests like urine tests or blood tests. While the urine tests help in detecting abnormalities such as dehydration, blood tests help in measuring the RBCs and WBCs to detect infections, or disorders like anaemia, which can lead to sunken fontanelles.
  • A comprehensive metabolic panel test that helps to detect if the body is suffering from malnutrition.

How to Prevent a Sunken Fontanelle

You can prevent a sunken fontanelle by taking utmost care of the most common cause of it – dehydration. It is essential that your baby’s dietary intake is full of nutrition, and his little body is well-hydrated.

  • Be sure to provide fluids to your baby at regular intervals to keep the body hydrated. Increase the amounts of fluid given if he is suffering from diarrhoea or vomiting.
  • Consult the doctor if you have any doubts about the feeding, or if you feel that the baby is in danger of being dehydrated.
  • Mothers must eat well and stay hydrated when they are breastfeeding.
  • When your child starts eating semi-solids and solids, make sure his diet is nutritious and well-balanced, to avoid any kind of growth hindrance or malnutrition.

When to Call the Doctor

While a slightly sunken soft spot can be normal, it is important to know when to contact the doctor for seeking help. If you notice a change in the fontanelles, or you observe that the fontanelles are not flat or have sunken inwards more than usual, you must realize that the soft spot on the baby’s head can prove to be dangerous, and you should contact the doctor immediately. Also, when the baby is not consuming enough fluids, or is suffering from diarrhea or vomiting, it is advisable to call the doctor.


While sunken fontanelles are mostly associated with dehydration, sometimes they may occur due to underlying causes other than dehydration. It is essential that, if a child is suffering from dehydration or malnutrition, you immediately seek medical attention. The doctor may provide some immediate fluids to the child in case of dehydration.

A sunken fontanelle is a mild symptom, and can be cured easily at the initial stage. But, neglecting it can result in fatal conditions. Medical attention at the proper time is the best way to keep your child healthy.

You do not have to be overly concerned with a soft, slightly sunken fontanelle. The worry can arise when it appears more sunken, or even bulging outwards. Proper care of the soft spot must be observed, as well as ensuring a healthy, well-balanced diet for your child. The latter takes care of fontanelles, as well as overall development! Contact your pediatrician for any non-routine behaviour you observe in your child, such as low consumption of food or fluids, to take more precautions.

Also Read:

How to Support Baby Brain Development
Infant Head Shape: What’s Normal and What’s Not?
Infant Shaking Head Side to Side: Is it Normal?

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Gauri Ratnam completed her Masters in English Literature from the University of Pune. She began her journey as a German translator soon after completing her graduation, but later moved on to pursue her passion for writing. Having written for both digital and print media in a varied range of industries, she has the ability to write relatable and well-researched content, benefical for anyone seeking advice or direction.