Pityriasis Versicolor (hyperpigmented)

Diagnosis: Pityriasis Versicolor (hyperpigmented)

Hyperpigmented macules and patches covered by fine scale (Some lesions have become confluent).

Clinical Presentation

Hyperpigmented macules and patches covered by fine scale (Some lesions have become confluent).

Clinical History

Submitted by Alaa Saad. Originally posted December 14, 2010.

Treatment

See case discussion.

Differential Diagnosis

• Vitiligo • Pityriasis alba • Post-inflammatory hypopigmentation • Tinea corporis • Seborrheic dermatitis • Confluent and reticulated papillomatosis • Secondary syphilis

Key Learnings

• 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: pityriasis, versicolor, hyperpigmented, alaa saad