Incidence of Mastoiditis in Immunocompetent Adults
Mastoiditis is rare in immunocompetent adults, with an incidence of approximately 0.99 cases per 100,000 adults per year. 1
Epidemiology and Risk Factors
- Mastoiditis is significantly more common in children than in adults, with the highest global incidence rates in children 1-4 years of age (61 new episodes per 100 children per year) 2
- In adults, the incidence has remained relatively stable over time, even following the introduction of guidelines to reduce antibiotic use for acute otitis media (AOM) 2
- Immunocompromised status is a significant risk factor for developing mastoiditis, particularly fungal mastoiditis, which is extremely rare in immunocompetent individuals 3, 4, 5
- When mastoiditis does occur in immunocompetent adults, it often presents with atypical features and may have a more insidious development 1
Clinical Presentation in Immunocompetent Adults
- The typical clinical presentation (postauricular swelling, erythema, tenderness, protrusion of the auricle, fever) is observed in only about 48% of adult cases 1
- Adults may present with unexplained progressive otalgia despite a non-inflamed and air-containing middle ear space 3
- Latent forms with prolonged and insidious development followed by rapid clinical deterioration are more common in adults than in children 1
- Older adults appear to be at higher risk for complications, even when immunocompetent 3, 1
Complications and Outcomes
- Intracranial complications occur more frequently in adult mastoiditis than in pediatric cases, with meningitis being the most common (reported in approximately 15 cases out of 62 adults with mastoiditis in one study) 1
- Other reported complications include facial nerve paralysis (11/62 cases), labyrinthitis (8/62 cases), and more rarely, meningo-encephalitis and lateral sinus thrombosis 1
- Brain abscess is the most common intracranial complication of otitis media overall, with an estimated incidence of 1 per million per annum 2
- Fungal mastoiditis, though extremely rare in immunocompetent adults, can occur and may lead to serious complications if not recognized early 3, 6
Management Considerations
- While mastoiditis treatment traditionally involved cortical mastoidectomy, there is a trend toward non-surgical management with intravenous antibiotics, either alone or combined with myringotomy 2
- In adults with uncomplicated mastoiditis, conservative treatment with antibiotics alone may be successful in approximately 69% of cases 1
- For fungal mastoiditis, which is rare but can occur in immunocompetent adults, early surgical debridement followed by antifungal therapy is often necessary 3, 6
- CT scanning should be considered if there is failure to improve after 48 hours of conservative treatment or if there is clinical deterioration 2
Conclusion
Mastoiditis in immunocompetent adults is uncommon, with an incidence of approximately 0.99 cases per 100,000 adults per year. The presentation is often atypical, and the risk of complications, particularly intracranial ones, is higher than in children. Clinicians should maintain a high index of suspicion, especially in older adults with unexplained otalgia or treatment-resistant otitis media.