A 24-year old male had multiple, small hypopigmented macules on the upper chest and back for 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 ago which subsided with treatment. The most appropriate investigation to confirm the diagnosis:

Ans. a. KOH preparation (Ref: Roxburgh's 17/e p37-39)Multiple, small hypopigmented macules on the upper chest and back which are circular, arranged around follicles coalesced to form large sheets with fine scaling are seen in Pityriasis versicolor. The most appropriate investigation to confirm the diagnosis is KOH preparation.Diagnosis in this 25-year-old girl presenting with erythematous papules on the face as seen in the figure with exacerbation of lesions on excessive sweating, sun exposure and emotional disturbance is pityriasis versicolor, diagnosed by KOH mount showing short branched hyphae with spores (Spagheti and Meatball appearance).Tinea/Pityriasis versicolorCaused by Malasezia furfur (Pityrosporom ovale)Q.Clinical features:Multiple, small, scaly, hypopigmented macules develop insidiously over the skin of chest and back in young adultsQ.Macules start around the hair follicles and merge gradually with each other to form large areasQ.Diagnosis:Examination of scales in 10% KOH- shows Spaghetti and meatball appearanceQWood camp examination: Apple green fluoresceneQ.Skin surface biopsyTreatment:Griseofulvin is not effectiveQKetoconazole/itraconazole for systemic therapyQ.Clotrimazole, miconazole, econazole, selenium disulfide and sodium thiosulfate for local application.Hypopigmented PatchPityriasis alba (simplex)Pityriasis versicolorIndeterminate leprosy* Primarily in young childrenQ before the age of puberty* More common in children in hill stationsQ* Asymptomatic, ill defined, hypopigmented scaly macules mostly on cheeksQ or other part of face* RecurrentQ* Scaly lesionQ* Non anaestheticQ* Rare in children but common in young adultQ* Macules appear on upper trunk and shoulderQ, face involvement is rare.* Hands and lower limbs are usually not involved* Systemic steroids aggravate lesion* RecurrentQ* Scaly lesionQ* Non anaestheticQ* More common in childrenQ* More frequent in patient belonging to high leprosy prevalence states as TamilnaduQ, BiharQ* Non scaly lesionQ with epidermal atrophyQ* Anaesthetic f non anaesthetic lesionQ