Prevalence and Etiological Agents of Onychomycosis.

Onychomycosis is a common nail infection caused by dermatophytes, yeast or other non-dermatophyte molds and have been known to be associated with significant physical and psychological morbidity. This study was performed to determine the prevalence and the etiologic agents of onychomycosis in patients attending RIMS, Imphal, Manipur for a period of two years (January 2010 to December 2012). Nail samples of 347 clinically suspected cases of onycomycosis attending dermatology OPD RIMS, Manipur were collected and were subjected to potassium hydroxide (KOH) mounts for direct microscopy and fungal culture on Sabouraud’s dextrose agar (SDA). The male female ratio of the participants was 1:1.81 (165 male and 302 female). Out of 467, 399 (85.44.%) were positive by culture and KOH mount. Young adults in the age group of 21-30 years were commonly affected. In female patients finger nail infection was more common than toe nail infection. Both toe and finger nails involvement were noticed in nine patients of which two were male and seven were female. The most frequently isolated fungus was dermatophytes, in 107 (40.38%) patients followed by Aspergillus spp in 101 (38.11%) and Candida spp in 17 (6.4%). This study demonstrated that dermatophytes, as well as moulds especially Aspergillus spp are commonly isolated from onychomycosis patients in our region.

Comparison of potassium hydroxide mount and mycological culture with histopathologic examination using periodic acid-Schiff staining of the nail clippings in the diagnosis of onychomycosis.

BACKGROUND: Onychomycosis is a common problem noticed in clinical practice. Currently available standard laboratory methods show inconsistent sensitivity; hence there is a need for newer methods of detection. AIMS: This study involves comparison of standard laboratory tests in the diagnosis of onychomycosis, namely, potassium hydroxide mount (KOH mount) and mycological culture, with histopathologic examination using periodic acid-Schiff (PAS) staining of the nail clippings. METHODS: A total of 101 patients with clinically suspected onychomycosis were selected. Nail scrapings and clippings were subjected to KOH mount for direct microscopic examination, culture using Sabouraud's dextrose agar (with and without antibiotics) and histopathologic examination with PAS staining (HP/PAS). Statistical analysis was done by McNemar's test. RESULTS: Direct microscopy with KOH mount, mycological culture, and HP/PAS showed positive results in 54 (53%), 35 (35%), and 76 (75%) patients respectively. Laboratory evidence of fungal infection was obtained in 84 samples by at least one of these three methods. Using this as the denominator, HP/PAS had a sensitivity of 90%, which was significantly higher compared to that of KOH mount (64%) or mycological culture (42%). CONCLUSIONS: Histopathologic diagnosis with PAS staining of nail clippings was the most sensitive among the tests. It was easy to perform, rapid, and gave significantly higher rates of detection of onychomycosis compared to the standard methods, namely KOH mount and mycological culture.

Evaluation of impression smear in the diagnosis of fungal keratitis.

PURPOSE: To evaluate and compare impression smear with the conventional mechanical corneal scraping by potassium hydroxide (KOH) method in the diagnosis of fungal keratitis. MATERIALS AND METHODS: Fifty consecutive cases of clinically suspected fungal keratitis were included. Under topical anesthesia, impression smear was obtained from the lesion, followed by the conventional mechanical scraping and both were transferred to sterile glass slides. The slides were examined under direct microscopy with KOH 10% wet mount. Impression smear KOH was compared with the scraping KOH and culture. RESULTS: The KOH smear was positive in 36 (72%) patients with impression smear technique and positive in 35 (70%) patients from corneal scrapings. Sensitivity of impression smear technique as compared to scraping was 97.14%, specificity 92.86%, positive predictive value 94.4%, negative predictive value 92.86%, false positive rate 5.56%, false negative rate 7.14% and accuracy was 94%. As compared to culture, the sensitivity was 100%, specificity 46.67%, positive predictive value 55.56%, negative predictive value 100%, false positive rate 53.33%, false negative rate 0% and accuracy was 68%. CONCLUSION: Impression smear KOH examination is comparable to conventional mechanical corneal scraping KOH examination in making a tentative diagnosis of fungal keratitis and can be accurately relied upon for initiating anti-fungal therapy.

Role of potassium hydroxide mount in rapid diagnosis of fungal corneal ulcers.

The aim of the study was to establish the importance of KOH mount in rapid diagnosis of fungal corneal ulcers. Corneal scrapings were collected from 50 patients with corneal ulcers where clinical features suggested fungal aetiology and ulcers showed no signs of healing on initial treatment. Corneal scrapings were subjected to wet mount with 10% KOH, Gram's stain, and culture on SDA media. Wet mount showed fungal elements in 34 cases (68%) and were classified according to morphology. Gram's stain of corneal scrapings did not provide much help. Fungal culture was positive in 9 (26.4%) out of 34 cases. Specific antifungal treatment was instituted in all cases that showed positive wet mount without waiting for culture reports and on follow-up all these 34 patients showed improvement. Thus wet mount with 10% KOH can be relied upon as the singlemost important screening tool for rapid diagnosis of fungal corneal ulcer and treatment should be dispensed on its basis.

Early diagnosis of mycotic keratitis: predictive value of potassium hydroxide preparation.

Potassium hydroxide (KOH) preparation is an underutilized modality in the diagnosis of mycotic keratitis. We have earlier shown its utility in the diagnosis of Nocardia and Acanthamoeba keratitis. The aim of this study was (i) to evaluate the sensitivity, specificity and predictive value of KOH preparation, and (ii) to compare its efficacy with other methods of corneal scraping examination, for the diagnosis of mycotic keratitis. The study was conducted in two phases. In phase I, randomized corneal scrapings were examined by KOH, Gram's stain, and lactophenol cotton blue (LPCB) in 91 infectious keratitis subjects. In phase II, 53 corneal scrapings were stained with KOH and calcofluor white (CFW), and viewed with bright field (KOH) and fluorescence (CFW) microscopy. The KOH and CFW readings were recorded by an observer masked to the clinical findings and culture results. Nineteen scrapings were examined by two masked observers. In 22 culture positive fungal keratitis patients in phase I, the sensitivity of KOH, Gram's stain, and LPCB methods was 100%, 86.4%, and 77.3%, respectively. In phase II, the specificities of KOH and CFW were identical (83.8%), while the sensitivities were 81.2% and 93.7%, respectively (p = 0.59), in 16 culture positive mycotic keratitis patients. There was no significant difference between the negative and positive predictive values of KOH and CFW. Furthermore, no significant interobserver variability was found in the specificity and sensitivity. The KOH method compares well with other microscopy methods in the diagnosis of keratomycosis and has a definite place in the armamentarium of diagnostic techniques.