See a doctor within 1 to 2 days if:

• You or your child experiences a head injury, even if emergency care isn't required
  (The American Academy of Pediatrics recommends that you call your child's doctor for advice if your child receives anything more than a light bump on the head.If your child doesn't have signs of a serious head injury, and if your child remains alert, moves normally and responds to you, the injury is probably mild and usually doesn't need further testing. In this case, if your child wants to nap, it's OK to let him or her sleep. If worrisome signs develop later, seek emergency care.)

Seek emergency care for an adult or child who experiences 
a head injury and symptoms such as:

• Repeated vomiting
  
• A loss of consciousness lasting longer than 30 seconds
  
• A headache that gets worse over time
  
• Changes in his or her behavior, such as irritability
  
• Changes in physical coordination, such as stumbling or clumsiness
  
• Confusion or disorientation, such as difficulty recognizing people or places
  
• Slurred speech or other changes in speech