Early recurrences of otitis media: reinfection or relapse?

In a prospective study, 36 (35%) of 103 patients had early recurrence of acute otitis media. We wished to identify risk factors for early recurrences (those recurring within 1 month of initial diagnosis) and to determine if the second episode was caused by the same pathogen (relapse) or a new organism (reinfection). When the same bacterial species was recovered in both episodes, Streptococcus pneumoniae were serotyped and Haemophilus influenzae were classified by biotypes and by electrophoretic pattern of the outer membrane proteins. Twenty-nine patients underwent tympanocentesis at the time of the recurrent episode. In 13, no pathogen was recovered either initially or at the time of recurrence. Twelve (75%) of the remaining 16 patients had reinfection; only four (25%) had relapse. Thus, early recurrences of acute otitis media were more often caused by a new organism. This finding suggests that underlying susceptibility to middle ear infection is important in the development of recurrent otitis media. Pediatricians should not assume that early recurrences are necessarily the result of failure of initial treatment. Tympanocentesis may be helpful in this setting to aid in choosing appropriate antibiotic therapy.