A 24-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 ago which subsided with treatment. The most appropriate investigation to confirm the diagnosis is
Pityriasis Versicolor (PV) Morphology:- Hypopigmented, (less frequently erythematous or hyperpigmented, so called versicolor) scaly, and perifollicular macules. Frequently coalesce but invariably the perifollicular character of the lesions is retained at the periphery of the lesions. Scaling is branny and can be accentuated, if the lesion is scratched (e.g., with help of a glass slide). Investigations:- KOH mount shows a mixture of sho, branched hyphae and spores described as spaghetti and meat ball appearance. Diagnosis:- Diagnosis of PV is based on presence of: Hypopigmented, perifollicular macules that become confluent. Lesions appear to be sitting on the skin. Branny scales, accentuated by scratching with glass slide. Upper trunk and neck. KOH mount confirmatory. Treatment:- Though the fungal infection is controlled easily, the hypopigmentation often persists. Topical agents:- Imidazoles: Ketoconazole, 2% applied daily for 4 weeks. Selenium sulfide: 2.5% lotion in a detergent base, used weekly for 4 weeks. It can cause irritation (prevented by diluting the lotion with water). Systemic agents:- Needed in extensive lesions or when recurrences are frequent: Ketoconazole, 200 mg daily for three consecutive days. Fluconazole, 400 mg single dose. Itraconazole, 200 mg daily for 7 days. Ref:- NEENA KHANNA; pg num:- 291,292
Slit skin smear from discrete macules
Tzanck test
Skin biopsy of coalesced macules
Potassium hydroxide preparation of scales
Skin lesions and disorders of pigmentation