Inflammation of middle ear spreads into mastoid air cells via the "aditus ad antrum"
Vast majority of acute<unk>  occurs as a result of, or simultaneous with, acute otitis media<unk>  is unlikely if middle ear examination is normal<unk>  is unlikely if middle ear examination is normal
S. pneumo (22%)
S. pyogenes (16%)
S. aureus (7%)
H. flu
P. aeruginosa
Mastoiditis
Auricular hematoma
Acute otitis media
Auricular perichondritis
Sinusitis
Cholesteatoma
Labyrinthitis
Contact dermatitis