1. Malignant otitis externa
Definition; Malignant otitis externa is an aggressive & potentially life-threating infection of the soft
tissues of the external ear & surrounding structures ,quickly spreading to involve the periostium &
bone of the skull base.
Malignant otitis externa is a misnomer as it is not a neoplastic process. It has been suggested that
necrotizing external otitis should be used for aggressive soft tissue infection in absence of bony
involvement& that skull base osteomylelitis be used for the condition once bone infection is
confirmed.
Staging (clinicopathological classification system)
Stage 1 clinical evidence of malignant otitis externa with infection of the soft tissues beyond
the external auditory canal but negative Tc-99 bone scan.
Stage 2 soft tissues infection beyond external auditory canal with positive Tc-99 bone scan.
Stage 3 as above, but with cranial nerve paralysis.
3a single cranial nerve, 3b multiple cranial nerve paralysis.
Stage 4 meningitis,empyema, sinus thrombosis, or brain abscess.
Pathology
Malignant otitis externa is a end stage of a severe infection that originate from the external auditory
canal & progresses through cellulitis, chondritis,periostitis, osteitis, & finally osteomyelitis. The
infection spread through the fissures of santorini. Malignant otitis externa mainly affect Haversian
system of compact bone. Otic capsule is usually spared.
Bacteriology
Pseudomonas aeruginosa is the common pathogen.
DM & AIDS are predisposed to malignant otitis externa.
Diagnosis;
Malignant otitis externa is a clinical diagnosis made on the basis of pain, exudates, granulations &
oedema of the EAC often supported by a positive bone scan and /or the presence of microabscess at
surgery.
ESR & C-reactive protein are raised.
Tc -99m bone scan will detect early bone involvement. As this isotope is absorded by osteoclast &
osteoblast that continue remodelling after the infection has resovled, the scan may remain positive
for upto 9 months. Gallium is absorbed by leucocytes & is more sensitive monitor of infection. The

2. scan quickly returns to normal after infection has resolved, is a good measure to ascertain when to
terminate the treatment.
Outcomes & complications
As awareness of the condition & anti-pseudomonas antibiotic therapy has improved, the mortality &
complication rate from malignant otitis externa has decreased dramatically.
The facial nerve paralysis occurs 60% cases & last four cranial nerves can be affected.
Management options
Aural toilet; local toilet to the EAC is essential to control the granulation tissues & improve local pain
control.
Systemic antibiotic;
Choice of antibiotic is antipseudomonas . The drug should be given at least six weeks & in advanced
cases several months. Parenteral antibiotic ciprofloxacin with /without aminoglycoside and /or
ceftazidime. Transition to oral antibiotic once the C- reactive protein, & ESR start to fall.
Hyperboric oxygen.
Surgery : for the removal of sequestra, collections of pus & debridement of necrotized &
granulations tissues can be beneficial.