Patients at risk:
(1) elderly patients with diabetes mellitus, especially those with microvascular disease (as manifested by diabetic retinopathy or nephropathy)
(2) very young infants with comorbid conditions
(3) rarely AIDS patients or other immunocompromised patients
Infection starts in the external ear canal, then spreads to surrounding structures:
(1) cellulitis
(2) osteomyelitis in adjacent bones
(3) thrombosis of lateral and sigmoid sinuses
Symptoms:
(1) otalgia
(2) otorrhea
(3) decreased hearing
(4) fever is uncommon
Findings:
(1) The external ear canal is swollen, inflamed, and/or erythematous, with a purulent discharge. Granulation tissue is often present in the canal.
(2) The patient may not appear ill.
(3) A palsy of the facial or other cranial nerves may develop.
(4) Most patients do not have lymphadenopathy.
Imaging studies (MRI, bone scans) of the skull can indicate the extent of disease and can document bony involvement.
The presence of cranial nerve palsy or CNS deficit indicates a poor prognosis.
