(HealthDay News) -- When the mastoid bone in the skull becomes infected, it's called mastoiditis. Often it's triggered by an infection in the middle ear, and it's most common in children.

The U.S. National Library of Medicine mentions these symptoms that may indicate mastoiditis:

• Fluid draining from the ear.
• Pain or discomfort in the ear.
• A fever, which may suddenly rise and get very high.
• Headache.
• Loss of hearing.
• Reddening of the ear or the area behind it.
• Swelling of the area behind the ear, which can make the ear protrude.