Bulging Fontanelles: Causes, Symptoms, and Treatment
Medically reviewed by Achuta Uppu, MD, Internal Medicine. Last reviewed: October 23, 2026.
What kind of doctor treats Bulging Fontanelles?
A bulging fontanelle needs emergency care right away, so take your baby to the nearest emergency room. Babies are treated by a pediatrician, a doctor who cares for children, and may see a pediatric neurologist or neurosurgeon for brain problems. A direct primary care or concierge doctor can be a first stop for an evaluation and can refer you to a specialist when needed.
What are bulging fontanelles?
Fontanelles are the soft spots on a baby's head where the skull bones have not yet joined together. They let the brain and skull grow during the first year of life. The back soft spot usually closes by age 1 to 2 months. The one on top of the head usually closes within 7 to 19 months.
A fontanelle should feel firm and very slightly curved inward. A bulging fontanelle is a soft spot that curves outward. It happens when fluid builds up in the brain or the brain swells, which raises pressure inside the skull. It is a warning sign that needs care right away.
Symptoms
The main sign is a soft spot that stays tense or bulging even when your baby is calm and held upright. A soft spot may look full when a baby cries, lies down, or vomits, but it should go back to normal when the baby is calm with the head up.
Things the doctor will ask about include fever, unusual sleepiness, and irritability. In a baby with hydrocephalus, a buildup of fluid in the brain, an unusually large head is the main sign. The baby may also vomit and be hard to wake.
Causes and who gets it
Bulging fontanelles happen only in babies, because older children have closed soft spots. Causes include:
- Hydrocephalus, a buildup of fluid inside the skull.
- Meningitis, an infection of the membranes covering the brain.
- Encephalitis, swelling of the brain, most often from an infection.
- Increased pressure inside the skull from other causes.
It affects both boys and girls and can occur in any baby. The cause sets the treatment, so finding out why the spot bulges matters.
How doctors diagnose it
The doctor starts with a physical exam and questions about the baby's health. The doctor checks whether the soft spot bulges all the time or only at certain moments, and looks for other symptoms such as fever or unusual sleepiness.
Tests may include a CT scan of the head, a special X-ray that shows the brain. They may also include an MRI scan of the head, which uses magnets to make detailed pictures. Another test is a spinal tap, which takes a small sample of the fluid around the spine to check for infection.
Treatment
Treatment depends on the cause. A truly bulging fontanelle is an emergency, and care starts right away.
For hydrocephalus, treatment usually involves surgery to place a shunt, a plastic tube that moves the extra fluid to another area of the body where it can be absorbed. With treatment, many people lead normal lives with few limits. For meningitis or encephalitis, doctors treat the infection and watch the baby closely, often in the hospital.
When to see a doctor
A truly bulging fontanelle is an emergency. Call 911 or go to the emergency room right away for any infant who has a truly bulging soft spot, especially if it occurs along with fever or excess drowsiness.
How a direct primary care or concierge doctor fits in
A direct primary care doctor charges a flat monthly fee instead of billing insurance, while a concierge doctor usually charges more and often works alongside insurance. After an emergency, this kind of doctor can follow your baby's recovery, track growth and development, and coordinate visits with specialists.
Common questions
Is a bulging fontanelle always an emergency?
It depends. A soft spot that bulges only during crying and returns to normal when the baby is calm is not a true bulging fontanelle. A soft spot that stays tense or bulging needs emergency care right away, especially with fever or drowsiness.
When do fontanelles close?
The back soft spot most often closes by age 1 to 2 months. The soft spot on top of the head most often closes within 7 to 19 months. The doctor checks them at regular visits.
What does hydrocephalus mean for my baby?
Hydrocephalus is the buildup of too much cerebrospinal fluid, the fluid that normally cushions the brain. Too much of it puts harmful pressure on the brain. If untreated, it is usually fatal, but with treatment, which usually involves a shunt, many people lead normal lives with few limitations.
Can dehydration cause a bulging soft spot?
No. Dehydration usually does the opposite. In infants and young children, signs of dehydration include a dry mouth and tongue, crying without tears, no wet diapers for 3 hours or more, sunken eyes, and unusual sleepiness. Severe dehydration needs medical help right away.
Sources
- MedlinePlus - Fontanelles - bulging
- MedlinePlus - Hydrocephalus | Water on the Brain
- MedlinePlus - Dehydration
Medical Disclaimer
This content is for general educational and informational purposes only and is not medical advice. It is not a substitute for professional medical advice, diagnosis, or treatment, and reading it does not create a doctor-patient relationship. Always seek the advice of your physician or another qualified health provider with any questions about a medical condition, and never disregard or delay seeking professional advice because of something you read here. If you think you may have a medical emergency, call 911 (or your local emergency number) immediately.
