Myringitis Bullosa: Etiology
Bullous myringitis is caused by the same bacterial pathogens responsible for acute otitis media, primarily Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis, and represents a specific manifestation of acute middle ear infection rather than a distinct disease entity. 1
Primary Causative Organisms
- The bacterial pathogens in bullous myringitis are identical to those found in acute otitis media (AOM), with S. pneumoniae, H. influenzae, and M. catarrhalis being the predominant organisms 1
- Studies show a relative increase in the proportion of Streptococcus pneumoniae cases in bullous myringitis compared to AOM without bullae 2
- The distribution of viral and bacterial pathogens in bullous myringitis mirrors that of standard AOM, except for this pneumococcal predominance 2
Viral Associations and Upper Respiratory Infections
- Bullous myringitis is commonly preceded or accompanied by upper respiratory tract infection, occurring most frequently in winter months 3
- Despite historical associations with Mycoplasma pneumoniae and influenza virus, complement fixation antibody studies failed to implicate M. pneumoniae, influenza virus types A or B, or adenovirus as causal agents in the majority of cases 3
- The condition is typically preceded by viral upper respiratory infection, which creates mucosal edema and Eustachian tube dysfunction, allowing bacterial colonization of the middle ear 4
Pathophysiological Context
- Bullous myringitis should be understood as a rare and peculiar manifestation of acute otitis media rather than a separate disease entity 1
- The formation of hemorrhagic bullae on the tympanic membrane and medial external auditory canal wall represents an exaggerated inflammatory response to the same bacterial pathogens that cause standard AOM 1, 5
- Viral infection of the nasopharyngeal and Eustachian tube epithelium precedes bacterial invasion, with AOM always being preceded by viral URTI 4
Clinical Implications of Etiology
- Children with bullous myringitis are typically older than those with standard AOM (median age 4.3 years vs 18 months), suggesting age-related differences in inflammatory response 2
- Patients with bullous myringitis present with more severe symptoms at diagnosis, including moderately severe to severe otalgia, compared to AOM without bullae 3, 2
- The same bacterial colonization and biofilm formation mechanisms that occur in standard AOM apply to bullous myringitis 4
Important Clinical Caveat
The historical attribution of bullous myringitis to Mycoplasma pneumoniae has been largely disproven by serological studies, and treatment should target the same bacterial pathogens as standard acute otitis media 3. The condition may rarely progress to serious complications including meningoencephalitis, emphasizing the importance of recognizing it as a manifestation of acute bacterial middle ear infection 6.