From the FDA Drug Label
Ketoconazole Cream 2% is indicated for the topical treatment of ... tinea (pityriasis) versicolor caused by Malassezia furfur (Pityrosporum orbiculare); Microbiology: ...the organism responsible for tinea versicolor, Malassezia furfur (Pityrosporum orbiculare).
The fungus responsible for Pityriasis versicolor infection is Malassezia furfur (also known as Pityrosporum orbiculare) 1 1.
- Key points:
- Fungus name: Malassezia furfur
- Alternative name: Pityrosporum orbiculare
- Infection: Pityriasis versicolor
From the Research
Pityriasis versicolor is caused by the yeast Malassezia, with various species such as M. furfur and M. japonica implicated in the infection. This common superficial fungal infection presents as scaly patches on the skin that may appear lighter or darker than surrounding skin, often on the chest, back, and shoulders. The diagnosis typically relies on recognizing characteristic clinical features, and due to the wide variability in its clinical presentation, recognizing the differential diagnosis is critical 2.
Key Points
- The infection occurs when these lipophilic yeasts, which normally live on human skin, convert from their round form to a hyphal form that invades the stratum corneum.
- Warm, humid environments and oily skin promote overgrowth of these fungi, which is why the condition often recurs and may require maintenance therapy with antifungal shampoo once or twice monthly to prevent relapse.
- Treatment typically involves topical antifungal medications such as ketoconazole 2% shampoo applied to affected areas for 5-10 minutes daily for 1-2 weeks, selenium sulfide 2.5% lotion, or terbinafine cream.
- For widespread cases, oral antifungal medications like fluconazole (400mg once weekly for 2-4 weeks) or itraconazole (200mg daily for 5-7 days) may be prescribed, with itraconazole 200mg daily for 28 days being the most effective treatment for recurrent and disseminated cases 3.
- Patient education and the promotion of good personal hygiene are pivotal to reduce the risk of recurrence, and in recurrent cases, particularly during warmer and more humid periods, prolonged prophylaxis with topical agents should be considered 2.
Fungus Identification
The Malassezia species, including M. furfur and M. japonica, are the primary fungi responsible for Pityriasis versicolor infection, as identified in various studies 4, 5, 3. The most recent and highest quality study, published in 2023, confirms that Malassezia is the causative agent of Pityriasis versicolor 2.