[A case of onychomycosis caused by Aspergillus sydowii].

Onychomyosis caused by Aspergillus sydowii is rare and difficult to diagnose. We report a case in which this disease was diagnosed by molecular-biological methods. The patient was a 53-year-old woman without any notable past history. She visited our hospital complaining of itching around the right first toenail in June 2010, although she had noticed nail opacification for 4 years. Opaque thickening of the nail, covering 57.3% of the normal nail area, was observed. Direct microscopic examination revealed thick mycelia with septa and black spores. While colonies with a red brown center and a grayish blue-green margin were observed in culture on Sabouraud ' s glucose agar at 25℃, radially arranged conidia in the conidial head were observed in slide culture. Thus, onychomycosis caused by Aspergillus was suspected. There were no blood or biochemical test abnormalities. We directly extracted deoxyribonucleic acid from the nail and analyzed the base sequences of the internal transcribed spacer 1 and 2 regions of the ribosomal ribonucleic acid gene, and identified Aspergillus sydowii. Because the minimal inhibitory concentration of itraconazole (ITCZ) is 0.25 μg/ml, we administered pulse therapy with monthly 1-week cycles of oral ITCZ 400 mg / day for 3 consecutive months. The opaque area subsided to 17. 9% of the normal nail by 6 months after treatment completion. However, 3 months later, the opaque area increased again to 22. 3%, and the same fungus was isolated and identified. The 3-month ITCZ pulse therapy was repeated and the symptoms disappeared, with complete cure achieved by 3 months after the second therapy.