Otitis externa accounts for 1.1-1.3 per cent of patient presentations in primary care and 25 per cent of urgent referrals to ENT. This study aimed to explore otitis externa clinical decision-making at the primary-secondary care interface, otitis externa prevalence and recent trends in antimicrobial resistance in otitis externa related bacterial isolates and ototopical prescribing. This is a mixed-methods study drawing on data from primary and secondary care and open National Health Service sources. A total of 101 general practitioner survey respondents reported frequently prescribing oral antibiotics for otitis externa. General practitioner consultations for otitis externa increased 25 per cent over 15 years. General practitioner ototopical preparations cost the National Health Service £7 410 440 in 2006 and £11 325 241 in 2016. A total of 162 consecutive hospital otitis externa-related bacterial isolates yielded 128 pseudomonas species, with 18 that were resistant to gentamicin and 7 that were resistant to ciprofloxacin. Ten guidelines reviewed showed systematic inconsistencies. General practitioners reported regularly prescribing oral antibiotics for otitis externa. Antimicrobial drug resistance is common in otitis externa. The available guidance is suboptimal.