Infections of the ear can be divided into otitis externa and otitis media.

Otitis externa: In general, infection of the external auditory canal resembles infection of skin and soft tissue elsewhere. However, there are some notable differences. The canal is narrow and, as a result, foreign materials and fluid that enter can become trapped, causing irritation and maceration of the superficial tissues. Otitis externa can be subdivided into categories: acute localised; acute diffuse; chronic; and invasive (‘malignant’). However, except for invasive, they are rarely differentiated as such in clinical practice.

Otitis media: Acute otitis media is defined by the co-existence of fluid in the middle ear and signs and symptoms of acute illness. It can occur when oropharyngeal flora ascends the Eustachian tube and are not eliminated by the defence mechanisms of the middle ear. Otitis media is a common disease in children with frequent recurrence of infections. It is important to treat otitis media because possible complications include the loss of hearing. This could have adverse effects on the development of speech and behaviour in children. Symptomatic relief is suggested as the initial form of treatment with antibiotic therapy prescribed only upon reoccurrence of infection. The role of antibiotic treatment at the

first presentation of infection is a contentious issue as most infections are of viral origin. However, common bacteria causing otitis media, such as Streptococcus pneumoniae and Haemophilus influenzae can be isolated from ear swabs if the tympanic membrane has perforated. Other less common causes include S. aureus, S. pyogenes and Moraxella catarrhalis. Although uncommon in adults, the causative organisms and treatment of otitis media are the same as in children. An external ear swab is not useful in the investigation of otitis media unless there is perforation of the eardrum. Tympanocentesis, to sample middle ear effusion, is rarely justified.

PLEASE NOTE: Samples and accompanying relevant patient/ isolate data maybe referred for confirmatory or further laboratory testing to Reference laboratories. Relevant Public Health departments may also be notified IF a notifiable disease is identified under the Infectious Diseases (Amendment) Regulations 2020 (S.I. No. 53/2020).

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