Kavitha K1, Usha M. G2, Murugesh3, Chandrashekar N. R4
BACKGROUND
Pityriasis Versicolor is a superficial infection of the stratum corneum which is caused by a group of yeasts called Malassezia.
OBJECTIVES
To isolate and identify the causative fungi from clinically suspected cases of Pityriasis Versicolor by 10% KOH and to compare the results of 10% KOH with culture.
METHODS
100 clinically diagnosed cases of Pityriasis Versicolor of all age groups and both sexes, attending the Outpatient Department of Dermatology at Bapuji Hospital and Chitageri Hospital were included in this study. Skin scrapings from lesions of all cases were subjected to 10% KOH examination and culture. A control group of 50 healthy individuals was studied to know the normal fungal flora of the skin. Differentiation of all Malassezia species performed using morphological features and physiological tests including catalase reaction, Tween assimilation test and splitting of esculin.
RESULTS
Out of 100 clinically diagnosed Pityriasis Versicolor cases, 97(97%) cases showed characteristic arrangement of fungal elements in 10% KOH preparation and culture was positive in 68 cases. The most frequently isolated species was M. globosa (54.41%), followed by M. furfur (25%), M. sympodialis (11.76%) and M. obtusa (8.82%). In control group, M. globosa was the common isolate.
CONCLUSION
In comparison with culture results, the sensitivity and specificity of 10% KOH is 100% and 9.37% respectively. It does not require highly skilled personnel to perform or interpret results. The only disadvantage of KOH examination is that the Malassezia species cannot be differentiated. Culture is the gold standard, but it is time consuming and requires considerable expertise. Therefore, 10% KOH examination is a rapid, simple, sensitive and effective diagnostic test for Pityriasis Versicolor. M. globosa was the most common isolated species followed by M. furfur, M. sympodialis and M. obtusa.
