A24-year-old man had multiple, small hypopigmented macules on the upper chest and back for the last three months. The macules were circular, arranged around follicles and many had coalesced to form large sheets. The surface of the macules showed fine scaling. He had similar lesions one year age which subsided with treatment. The most appropriate investigation to confirm the diagnosis is –
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Adult patient (24 yrs)
Multiple small hypopigmented macules
On chest and back
Macules had started around follicle and then coalesced
Fine Scales
Recurrent after treatment


The clinical diagnosis is P.versicolor which can be confirmed by examination of scales as wet mounts after treatment with 10% KOH.
Potassium hydroxide preparation of scales
Slit skin smear from discrete macules
Tzanck test
Skin biopsy of coalesced macules