Malignant Otitis externa (MOE) is a life threatening, progressive bacterial infection of the external auditory canal (EAC), mastoid and skull base. It most commonly occurs in elderly diabetics or in an otherwise immune compromised host. In nearly all cases Pseudomonas aerugenosia is the causative organism(1,2). We report a case of malignant otitis externa caused by Enterobacter in a 10 month old immunocompetent infant.

A 10 month old girl, second sibling of non consanguineous parents, presented with complaint of purulent ear discharge from left ear since 2 months, intermittent fever of 100 – 101ºF and deformation of left ear since 1 month. There was no history of trauma or ear picking. Patient had already received 10 days of parenteral and local antibiotics with no response.

The girl was well nourished, had mild pallor and was febrile and irritable. The left ear was deformed with necrotic material seen all over the left external ear. On examination granulation tissue was seen occluding the external ear with erythema surrounding the pinna (Fig.1). Tympanic membrane could not be seen. There was no abscess collection on the surrounding areas and mastoid tenderness was not present. There was no cranial nerve palsy or other intracranial complication. CT scan of left temporal bone showed destruction of complete cartilageous and some bony part of external auditory canal with secondary opacification of mastoid air cells. Right side was normal.

Fig.1 Malignant Otitis Externa: Markedly deformed left ear with granulation and purulent tissue occluding the external ear.

Pus culture from ear swab revealed Enterobacter species after which antibiotics were modified according to sensitivity pattern. Local treatment with normal saline compresses were given. Fever and erythema subsided within 1 week. There was narrowing of the opening of the external auditory canal for which stent was placed to prevent complete closure. Patient was discharged after 3 weeks of parenteral antibiotics on oral antibiotics for 3 more weeks. Reconstruction of the deformed external ear was planned at a later date.

The diagnosis of malignant otitis externa is by two criteria: obligatory and occasional. The obligatory criteria are pain, edema, exudates, granulations, micro abscess (when operated), positive bone scan or failure of local treatment for more that 1 week, and possibility of Pseudomonas in culture. The occasional criteria include diabetes, cranial nerve involvement, positive radiograph, debilitating condition and old age(3). Our patient fulfilled the obligatory criteria.

Although rare, malignant otitis externa has been reported in children with diabetes and other immune compromised states(4,5). Complications include necrosis of the tympanic membrane, stenosis of EAC, auricular deformity and sensorineural and conductive hearing loss. Isolation of Enterobacter has not been reported earlier. Prolonged treatment with sensitive antibiotics is recommended for 6 to 8 weeks. Inadequate treatment can lead to recurrence of disease. Quinolones are generally avoided. Treatment can be guided by monitoring ESR and Gallium scans(6).

We are thankful to Dr Daljit Singh, Principal and Professor (Pediatrics), for his guidance.

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2. Midwinter KI, Gill KS, Spencer JA, Fraser ID. Osteomyelitis of the temporomandibular joint in patients with malignant otitis externa. J Laryngol Otol 1999; 113: 451-453.

3. Cohen D, Friedman P. The diagnostic criteria of malignant external otitis. Laryngol Otol 1987; 101: 216-221.

4. Paul AC, Justus A, Balraj A, Job A, Kirubakaran CP. Malignant otitis externa in an infant with selective IgA deficiency: a case report. Int J Pediatr Otorhinolaryngol 2001; 60: 141-145.

5. Sobie S, Brodsky L, Stanievich JF. Necrotizing external otitis in children: report of two cases and review of the literature. Laryngoscope 1987; 97: 598-601.