Otitis externa can be acute or chronic, diffuse or localized; and can be caused by infection, allergy, irritation or inflammation. It includes all inflammatory conditions of the auricle, external ear canal and outer surface of the tympanic membrane. It is a common problem, and although only 3 per cent of cases are referred from general practice to secondary care, it still constitutes one in six new patient referrals and 30 per cent of people seen in an ear, nose and throat (ENT) emergency clinic. There are very few good quality trials of treatment for acute otitis externa. A Cochrane review published in 20101 found 19 randomized controlled trials, only three of which were good quality.