Invasive external otitis

There are two patterns of invasive Aspergillus infections of the ear - chronic suppurative otitis media and invasive external otitis. Most probably the second follows from the first. Chronic suppurutive otitis media has been infrequently reported (Tiwari et al, 1995; Ibekwe et al, 1997; Attallah 2000; Khanna et al, 2000).

Aspergillus mastoiditis follows from invasive Aspergillus otitis (Petrak et al, 1985; Bickley et al, 1988; Cunningham et al, 1988; Stanley et al, 1988; Denning et al, 1989; Philips, et al 1990; Reiss et al 1991; Strauss & Fine, 1991; Hanna et al, 1993; Kim et al, 1993; Gordon & Giddings 1994; Harley et al, 1995; Yates et al, 1997; Munoz et al, 1998, Chen et al, 1999; Lizarralde et al, 1999; Slack et al, 1999; Ohki et al, 2001; Shelton et al, 2002; Finer et al, 2002; Bellini et al, 2003; Amonoo-Kuofi et al, 2005; Narozny et al, 2006; Ling & Sader, 2008; Mani et al, 2008; Parize et al, 2009; van Tol et al, 2009). The reported underlying conditions were AIDS, patients who suffered from acute leukemia, diabetes mellitus,, myelodysplasia, neuroblastoma, chronic otitis externa, systemic lupus erythematous and chronic granulomatous disease. In some cases, patients had no identified underlying diseases.

Among Aspergillus species, A. fumigatus, A. flavus, and A. niger were the predominant isolated species. In four reports, the Aspergillus species was not identified (Bickley et al, 1988; Philips, et al 1990; Chen et al, 1999; Narozny et al, 2006).

Clinical features are variable but include otalgia, hearing loss, facial nerve paralysis, fever and otorrhea. Usually the middle ear is destroyed and infection has extended into the mastoid and/or petrous bone. The invasive process can lead to even death if IEO is not recognized and treated early. Masked mastoiditis with an intact tympanic membrane has been rarely reported (Mani, 2008).

Extensive surgical debridement and systemic long-term antifungal therapy in association with appropriate management of the underlying condition may be curative, but extension into brain or an intercurrent infection is common and may be fatal. Previously the most commonly used antifungal agent was amphotericin B. This drug has been shown to be effective in the treatment of Aspergillus IEO, but its substantial toxicity profile must be taken into account, especially for patients with serious underlying co-morbidities (Parize et al, 2009). In some cases, itraconazole, voriconazole and caspofungin were used as the only antifungal drug or combined with another antifungal drug in the treatment of IEO. Based on the randomised clinical trial data and a few cases, voriconazole is the preferred primary therapy (Parize, 2009), with appropriate monitoring of plasma levels, assuming the isolate is susceptible in vitro.

Hyperbaric oxygen therapy was used for some Aspergillus IEO patients. This treatment is usually considered as an adjunctive therapy for refractory cases, although its efficacy remains debated (Phillips and Jones, 2005; Narozny et al, 2006).

Mohammad T. Hedayati, MSc, PhD

Department of Medical Mycology and Parasitology,Mazandaran University of Medical Sciences,Kilometer 18 Khazarabad Road,P.O. Box: 48175-1665Sari- IranFax: +98 151 354 3087

[email protected]

August 2010