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What is Open Fontanel?

In many cases, open fontanelles in dogs may be a sign of a condition called hydrocephalus, or an abnormal cerebrospinal fluid accumulation in the brain. Many believe that the increased pressure from this accumulation can cause the holes in the skull.  Hydrocephalus can be acquired or genetic, and can be a fatal condition. While it is often seen with open fontanelles in dogs, there are many cases of the presence of these skull holes without hydrocephalus.

Open fontanelles are holes in the skull that result from incomplete closures of the skull’s soft spots during normal growth in puppies. While for many dogs these soft spots close completely by 9 to 12 weeks of age, various smaller breeds of dogs, including toy and tea cups breeds, retain these holes past puppyhood. For Chihuahuas, the open fontanelles are considered a breed standard and are called moleras. For other dogs, they can be a symptom of a serious problem.

Symptoms of Open Fontanel in Dogs

The main symptom of an open fontanel is a soft spot or hole in the skull that remains into adulthood in a dog. For many dogs, these open fontanelles will cause no problems, but can result in injuries if subject to trauma. For other dogs, open fontanelles can be a sign of a bigger problem, such as hydrocephalus. Signs your dog may be experiencing this condition can include:

  • Presence of soft spots or holes in skull, usually located on the top of the head
  • Round, domed, or apple-shaped skull
  • Eyes directed downwards or upwards
  • Head pressing
  • Difficulties with housetraining
  • Puppies slow to grow
  • Restlessness
  • Aimless wandering
  • Lack of coordination
  • Blindness 
  • Seizures
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Causes of Open Fontanel in Dogs

Open fontanelles are often a congenital defect, but it can be an acquired condition due to a problem that puts pressure on the skull and cause it to be unable to fuse completely. Reasons for open fontanelles to occur include:

  • Genetic defect
  • Hydrocephalus
  • Swelling or infection of the brain
  • Brain tumor
  • Disease process that blocks cerebrospinal fluid drainage

Breeds commonly affected with open fontanelles include many toy breeds and short faced, or brachycephalic breeds, such as: 

  • Chihuahuas 
  • Miniature Dachshunds 
  • Pomeranians
  • Shih Tzus
  • Yorkshire Terriers 
  • Maltese
  • English Bulldogs 
  • Lhasa Apsos
  • Boston Terriers 
  • Cairn Terriers 
  • Pugs
  • Pekingese 
  • Toy Poodles
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Diagnosis of Open Fontanel in Dogs

If you’ve noticed a domed or apple-shaped appearance to your dog’s skull, or have felt soft spots past puppyhood, you should talk with your veterinarian. The sooner you seek medical advice, the better it may be for your dog. Be sure to inform your vet about any symptoms you may have seen. 

Your veterinarian will examine your dog and ask questions about any behavioral or neurological abnormalities. Imaging techniques can show the presence of an open fontanel, fluid accumulation, tumors, or other abnormalities, and can include X-rays, ultrasounds, CT scans or MRIs. Results from these tests can confirm the presence of an open fontanel, as well as a condition such as hydrocephalus.

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Treatment of Open Fontanel in Dogs

For some dogs, the presence of an open fontanel requires no treatment, but may necessitate some special handling. Often, these dogs are adopted into families without other animals or even children, with instructions to avoid any traumas to the head. While it may resolve in puppies, an open fontanel will remain with an adult dog throughout his entire life. For those dogs who have associated or concurrent problems, such as hydrocephalus, treatment is usually needed. 

Medications

If caught early, hydrocephalus is treated with medication to reduce both brain inflammation, such as with corticosteroids, and the amount of cerebrospinal fluid produced, often with omeprazole. More severe cases may also need anti-seizure medications, diuretics to reduce fluid production, and electrolytes.

Surgery

For a more permanent solution, a ventriculoperitoneal shunt can be placed. This is a small tube surgically implanted into a ventricle of the brain to take the excess cerebrospinal fluid and safely drain it to another part of the body. As your dog grows, additional surgeries are often required to re-fit the shunt. Complications of this procedure include infections, and over or under drainage. The success rate for a shunt is approximately 80%. While this procedure can help a case of hydrocephalus from worsening, it does not resolve the open fontanel itself.

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Recovery of Open Fontanel in Dogs

Recovery of an open fontanel in your dog will depend on the severity of his condition. If your dog has an open fontanel, but no other medical issues, then he can live a long and healthy life, so long as he receives no direct trauma to that area. If your dog’s condition is more severe, with associated hydrocephalus, treatment can help to resolve symptoms. While symptoms in some dogs may resolve in two years, other cases may need repeated treatments of medications or surgery to place or re-fit a shunt. You may need to administer medications or postoperative care to your dog at home, and ensure a safe and trauma free environment throughout his lifetime. 

Prevent open fontanelles and hydrocephalus in future generations by refraining from breeding affected dogs. If you have a breed of dog which is known for these conditions, monitor your puppy’s growth and seek advice from your veterinarian if you notice any of the associated symptoms.

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Open Fontanel Questions and Advice from Veterinary Professionals

Need pet health advice? Ask a vet

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Cavachon

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9 weeks

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Unknown severity

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3 found helpful

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Unknown severity

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Open Fontenele

Hi, I am looking at puchasing a puppy with an open fontanele at 9 weeks. Appears to be happy and not other issues. Should I be concerned?

July 17, 2020

Owner

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Dr. Michele K. DVM

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0 Recommendations

Thank you for your question. Open fontanelles are quite common in some breeds, and usually do close over the first few months of life. There are some open fontanelles that can cause problems, however and if it is very large, that may be something that you need to think about. Since I cannot see the puppy, it would probably be best to have a Veterinary exam before you buy her or him. They will be able to give you an idea as to whether this is a problem or not. I hope that all goes well for the puppy.

July 17, 2020

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Trixie

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French Bulldog

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9 Weeks

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Fair severity

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2 found helpful

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Fair severity

Has Symptoms

Hyperactivity
Vocal

I have a 9 week old french bulldog and she was the runt and the vet said she had an open fontanel and she is very busy (paces and runs) not sure if this is just puppy activeness or something else. Have our vet visit next week.

Aug. 13, 2018

Trixie's Owner

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3320 Recommendations

At nine weeks it can be difficult to distinguish erratic puppy behaviour from something pathological, an open fontanel means that the skull hasn’t closed and doesn’t always lead to other conditions (hydrocephalus etc…). You should keep a close eye on Trixie for the time being and visit your Veterinarian regularly to monitor for any other signs or symptoms. Regards Dr Callum Turner DVM

Aug. 14, 2018

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toto

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Chihuahua, poodle

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4 Months

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Fair severity

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2 found helpful

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Fair severity

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Unsteady
Open Fontanel

hi i am looking to purchase a puppy we have found one that is 4months old chihuahua cross poodle (I have 2 young children 4 and 8) puppy has open fontanel and can be seen to be unsteady on its feet do you think this is a sign if hydrocephulas and would this puppy be suited to our home concerned that I may end up with lots of vets bills and ongoing problems including puppy not living very long

July 27, 2018

toto's Owner

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3320 Recommendations

The presence of molera (fontanelle) on a pup doesn’t necessarily mean that this pup will be affected by hydrocephalus but if there are symptoms of being unsteady on the paws or any other concerning symptoms I would avoid purchasing the puppy. I cannot give you any assurances that Toto will be worry free or wouldn’t require regular veterinary care. Regards Dr Callum Turner DVM

July 28, 2018

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Tucker

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York Shire terrier

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5 Months

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Fair severity

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4 found helpful

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My yorkie puppy is 5 months old with open fontanel. He's healthy and isn't giving him any problems. I was just wondering if there is something I could be giving him to help it to close?

Sept. 5, 2017

Tucker's Owner

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3320 Recommendations

By five months of age the fontanel should be closed and if it isn’t closed already it never will; there are some conditions like hydrocephalus which would cause the fontanel to remain open and affect dogs should be neutered so that the problem isn’t passed on. You should speak with your Veterinarian about this condition as well as looking into protect for Tucker whilst playing outside. Regards Dr Callum Turner DVM https://wagwalking.com/condition/hydrocephalus

Sept. 5, 2017

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Peach

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Yorkie Pom

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3 Weeks

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Moderate severity

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0 found helpful

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Moderate severity

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Blind? Open Fontanels Disoriented

3 week old puppy seems to be blind, goes in circles and very disoriented. I noticed yesterday that she has 4 large fontanels (one on forehead, two on sides, and one at the back of her head and she looks different than her brother and sister) Her siblings are active and growing fast but she is quite a bit smaller. I am worried about what is wrong or what there is that I can do to help her? Has anyone been through this situation. By the way, the mom is a Pom that had an accidental breeding (she is 6.5) with a yorkie. The mom developed an infection so I took the puppies to help bottle feed since the Owner was unable to care for them

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Kisses

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Boston Terrier

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1 Month

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Mild severity

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0 found helpful

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Mild severity

Has Symptoms

Seizures
Seizures, Soft Spot, Slow Growth

I got this little baby a month ago when my boston terrier gave birth. Well this little nugget is having a seizures, have a soft spot on its head like an apple and she have a hard time walking like she is funny in that way but at the same time, you can see she has a hard time walking. She's also grow slow and easily lost her weight, I'm afraid she have a hydrocephalus,now she's only a haft of her brothers body. I didn't let her visit a vet after a month because I'm afraid and I don't have money. Could it be a Hydrocephalus?

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Halo

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Chihuahua Papillion mix

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1 Year

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Serious severity

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Serious severity

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Pain When Hitting The Top Of Head

Hello, I have a Papillion Chihuahua mix that has fontanelle. My 1 year old dog has hit his head several times and whaled and cried uncontrollably from the pain. I'm extremely frightened at this and want to do what I can to make his life as normal as possible. Is it possible to do a bone graft to cover it? and what are the health risks of surgery?

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Luwa

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Shorgi

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1 Month

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Mild severity

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Mild severity

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Stomach Pain
Skull Feels To Have A Hole
Troublem Pooping

Hi My dog is just a little puppy and well when we got her, she was 47 days old well anyway today my little Luwa couldn't poop like as if something was stuck in her, the other thing was when i petted her head she skull felt like there was a hole and well the other thing was that her stomach wasn't normal i dont know what to do could you help me

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Tinker Belle

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Chihuahua

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11 Years

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Moderate severity

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Moderate severity

Has Symptoms

Aimless Routine Pacing In A Pattern

I just rescued this baby. I thought at first it was anxiety then I noticed a pattern. She can do the routine pacing in the same route for over 30 minutes. She does have an open Fontanel which I know is normal in these breeds. Is there anything I can do for her or medicine to help her relax. Some days mild and others more often.

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