Round scaly patches on the chest
Background
This 25-year-old man has got round, brown, scaly patches over his chest. It has been diagnosed as a fungal infection but has not responded to oral terbinafine for two weeks.
What is this condition?
The superficial brown scaly patches are highly suggestive of a yeast infection called pityriasis versicolor — it is due to a yeast called Malassezia and not a dermatophyte fungus.
How can the diagnosis be confirmed?
The best way to confirm the diagnosis is by taking skin scrapings. The yeast pseudohyphae and spores are said to resemble spaghetti and meatballs when looked at using a potassium hydroxide wet preparation on microscopy.
How should it be treated?
Unfortunately, it does not respond to oral terbinafine, which is highly active against dermatophyte fungi but not the causative yeast. It can be treated by using topical azole shampoos or creams, or a short course of oral itraconazole.
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Comments
26 August 26
Hajar
Pityriasis rotunda
26 August 26
Viktoriia
Thank you for this excellent case. A very useful reminder of the importance of KOH microscopy in differentiating pityriasis versicolor from dermatophyte infection, especially when the clinical appearance can be misleading. Very practical and memorable.
26 August 26
Sami
Great info
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