Diagnosis: Pityriasis Versicolor (KOH examination)
Superficial skin scrapings from pityriasis (tinea) versicolor demonstrating yeast and short mycelial forms. Credit: Case submitted by Dr. Alaa Saad MD to dermRounds Dermatology Network
Superficial skin scrapings from pityriasis (tinea) versicolor demonstrating yeast and short mycelial forms. Credit: Case submitted by Dr. Alaa Saad MD to dermRounds Dermatology Network
Well-demarcated hypo- or hyperpigmented patches with fine scale on trunk and proximal extremities. Worsens in hot, humid weather. KOH confirms diagnosis.
Topical: selenium sulfide 2.5% lotion or ketoconazole 2% shampoo (applied to body 10 min). Oral: fluconazole 300mg × 2 doses or itraconazole 200mg/day × 5-7 days. Exercise after oral antifungals (eccrine secretion delivers drug to skin). Maintenance monthly.
• Vitiligo • Pityriasis alba • Post-inflammatory hypopigmentation • Tinea corporis • Seborrheic dermatitis • Confluent and reticulated papillomatosis • Secondary syphilis
• Caused by Malassezia yeast (dimorphic: yeast → mycelial/hyphal form in disease state) • "Spaghetti and meatballs" on KOH: short hyphae with round spores — pathognomonic • Color varies: hypo- or hyperpigmented patches depending on skin tone and sun exposure • Hypopigmentation mechanism: azelaic acid produced by Malassezia inhibits tyrosinase • High recurrence rate — maintenance therapy recommended • Wood lamp: yellow-gold fluorescence • Not truly contagious — Malassezia is part of normal skin flora; overgrowth is the issue • Risk factors: heat, humidity, oily skin, immunosuppression
Tags: dermatologist, dermatology, koh, pityriasis versicolor, tinea, yeast