Puppies are born with soft spots, or fontanels, in their skulls just like human babies. A puppy's fontanel can take longer than four months to close, but it's rare. Even more rare, some puppies' fontanels never close, indicating potentially serious health problems.
Open Fontanel Problems
Open soft spots are associated with a number of physical problems for puppies. While most puppies are unaware of having an open fontanel, there are two main physical problems associated with the condition. One is hydrocephalus, or water on the brain. Also, open-fontanel puppies face a high risk of brain damage from things as simple as careless grooming or falling off the sofa.
Breeds With Soft Spot Problems
Tiny designer dogs, such as teacup and toy breeds of Chihuahuas, Pomeranians, and Shih Tzus, are most likely to have problems from fontanels that do not close. Puppies with soft spots that never close should not be bred when reaching adulthood, as the condition and associated medical problems can pass on to future generations of puppies.