• | white (alba) patches surmounted by fine “bran-like” (pityron is Greek for bran) scales |
• | generally a disorder of young children |
• | gradually disappears with age (self-limited) |
clinical:
• | face most common in children |
• | upper arms in young women |
• | early lesion is erythematous, slightly scaling patch with indistinct margin |
• | usually only see subsequent lesion |
• | ddx: tinea versicolor - KOH (+), rarely facial involvement |
pathogenesis:
• | most feel that the initial event is a low-grade eczematous reaction |
• | i.e. may be simply another form of post-inflammatory hypopigmentation caused by mild exczematous dermatitis |
histology:
• | decreased melanocytes and melanosomes |
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