WHAT CAUSES ACUTE OTITIS-EXTERNA

External otitis is an extremely common condition and can affect betwee n five to twenty per cent of the patients attending ENT clinics (Hawke et al., 1984). Its precise pathogenesis remains unclear, despite seve ral aetiological classifications in the literature. The aim of this st udy was to investigate the relationship between infection, water expos ure and trauma and the development of acute otitis externa. The study comprised 100 patients with their first attack of otitis externa and 1 50 age and sex matched controls. In only 40 per cent of cases could a primary microbiological cause be found. There was no significant stati stical difference found between the two groups regarding the use of ag ents capable of traumatizing the external canal. Regular swimming, sho wering and hair washing were significantly more common in patients wit h acute otitis externa. Allergic disorders were nearly three times mor e common in the external otitis group suggesting a possible immunologi cal aetiology.