Mastoiditis is a bacterial infection in the mastoid process, the prominent bone behind the ear.

This disorder usually occurs when untreated or inadequately treated acute otitis media spreads from the middle ear into the surrounding bone—the mastoid process.

Usually, symptoms appear days to weeks after acute otitis media develops, as the spreading infection destroys the inner part of the mastoid process. A collection of pus (abscess) may form in the bone. The skin covering the mastoid process may become red, swollen, and tender, and the external ear is pushed sideways and down. Other symptoms are fever, pain around and within the ear, and a creamy, profuse discharge from the ear. The pain tends to be persistent and throbbing. Hearing loss can become progressively worse.

Computed tomography (CT) shows that the air cells (spaces in bone that normally contain air) in the mastoid process are filled with fluid. As mastoiditis progresses, the spaces enlarge. Inadequately treated mastoiditis can result in deafness, blood poisoning (sepsis), infection of the tissues covering the brain (meningitis), brain abscess, or death.

Treatment is with antibiotics given by vein. A sample of ear discharge is examined to identify the organism causing the infection and to determine the antibiotics most likely to eliminate the bacteria. Antibiotics may be given by mouth once the person starts to recover and are continued for at least 2 weeks. If an abscess has formed in the bone, surgical drainage (mastoidectomy) is required.

Last full review/revision February 2008 by Richard T. Miyamoto, MD