A diagnosis of AOM requires:

1. a history of acute onset of signs and symptoms,

2. the presence of middle-ear effusion (MEE), and

3. signs and symptoms of middle-ear inflammation.

Elements of the definition of AOM are all of the following:

1. Recent, usually abrupt, onset of signs and symptoms of middle-ear inflammation and MEE

2. The presence of MEE that is indicated by any of the following:

a. Bulging of the tympanic membrane

b. Limited or absent mobility of the tympanic membrane

c. Air-fluid level behind the tympanic membrane

d. Otorrhea

3. Signs or symptoms of middle-ear inflammation as indicated by either

a. Distinct erythema of the tympanic membrane or

b. Distinct otalgia (discomfort clearly referable to the ear[s] that results in interference with or precludes normal activity or sleep)