Uitti et al included 232 children aged 6 to 35 months diagnosed with acute otitis media (AOM) to their study. The otoscopic signs were recorded systematically. AOM was bilateral for 98 children and unilateral for 134 children. Children with bilateral AOM were more often <24 months than children with unilateral AOM (87% vs 75%; p = 0.032). The following severe otoscopic signs were observed in the bilateral and unilateral AOM group, respectively: moderate/marked bulging of tympanic membrane (63% and 40%; p = 0.001), purulent effusion (89% and 71%; p = 0.001), bulla formation (11% and 10%; p = 0.707), and hemorrhagic redness of tympanic membrane (7% and 10%; p = 0.386).