How can I differentiate between viral and bacterial otitis media in a primary care setting?

In a primary care setting, differentiating between viral and bacterial acute otitis media (AOM) is primarily clinical, as specific viral or bacterial testing is not routinely performed.

Key clinical features suggesting bacterial AOM include:

• Moderate to severe ear pain (otalgia) and/or persistent symptoms beyond 48-72 hours.
• Presence of fever, especially high fever (≥38°C in children under 3 months, ≥39°C in children 3-6 months).
• Bulging, erythematous tympanic membrane on otoscopy, often with middle ear effusion.
• Otorrhoea (ear discharge), which may indicate tympanic membrane perforation and bacterial infection.

Features more suggestive of viral AOM or a self-limiting illness include:

• Mild symptoms with less severe pain and low-grade or absent fever.
• Rapid onset but improvement within 48-72 hours without antibiotic treatment.
• Less pronounced tympanic membrane inflammation on otoscopy.

In practice, NICE guidelines recommend initial symptomatic management with analgesia (paracetamol or ibuprofen) and reserving antibiotics for those with more severe symptoms, bilateral infection in children under 2 years, otorrhoea, or if symptoms worsen or fail to improve after 3 days, reflecting a likely bacterial cause requiring treatment ¹.

Therefore, the differentiation relies on clinical assessment of symptom severity, duration, fever, otoscopic findings, and response to initial management rather than definitive laboratory tests in primary care ¹.