Fungal ear infection, mycotic otitis externa

Otomycosis is a superficial mycotic infection of the outer ear canal. The infection may be either subacute or acute and is characterized by inflammation, pruritus, scaling, and severe discomfort. The mycosis results in inflammation, superficial epithelial exfoliation, masses of debris containing hyphae, suppuration, and pain [1175].

Otomycosis is a chronic recurring mycosis. Burrow's solution or 5% aluminum acetate solution should be used to reduce the swelling and remove the debris. An aqueous solution of 0.02-0.1% phenyl mercuric acetate, 1% thymol in metacresyl acetate, or iodochlorohyroxyquin should be considered if drying the ear does not work satisfactorily. Antifungals with proven efficacy include nystatin, clotrimazole and econazole [199, 2157].

Inflammatory response with hyphae in the epithelium and in the exudate.

Direct examination

Epithelial debris placed in 10% KOH should reveal the presence of hyphae and in some instances the fruiting structures of the etiologic agent.

Isolation

The clinical material should be inoculated onto Sabouraud dextrose agar, IMA and incubated at 30°C. Since most of the fungi that cause this infection are sensitive to cycloheximide, a medium with cycloheximide has little value. Additional media containing antibacterial agents may be helpful if there is a heavy bacterial growth in the clinical material.

References

199. Bassiouny, A., T. Kamel, M. K. Moawad, and D. S. Hindawy. 1986. Broad spectrum antifungal agents in otomycosis. J Laryngol Otol. 100:867-73.

1175. Kaur, R., N. Mittal, M. Kakkar, A. K. Aggarwal, and M. D. Mathur. 2000. Otomycosis: a clinicomycologic study. Ear Nose Throat J. 79:606-9.

2157. Stern, J. C., M. K. Shah, and F. E. Lucente. 1988. In vitro effectiveness of 13 agents in otomycosis and review of the literature. Laryngoscope. 98:1173-7.