furfur

Furfur is the Latin word for bran and appears in several scientific terms. In biology, it is most commonly encountered in reference to Malassezia furfur, a lipophilic yeast that is part of the normal human skin microbiota and can become overgrown to cause pityriasis versicolor (tinea versicolor).

Malassezia furfur colonizes the stratum corneum and requires lipids to grow. Under favorable conditions such as heat, humidity, and occlusion, it proliferates and disrupts normal melanin production, leading to hypo- or hyperpigmented macules with fine scale, typically on the trunk and proximal limbs. The condition is usually benign and may be asymptomatic, though mild pruritus can occur.

Diagnosis combines clinical assessment with laboratory methods. Wood’s lamp examination may reveal copper-orange fluorescence of affected skin. Microscopy of skin scrapings stained with potassium hydroxide often shows a characteristic spaghetti-and-meatballs pattern, representing yeast cells and short hyphae. Culturing Malassezia furfur requires lipid-rich media, such as modified Dixon agar, because of the organism’s lipid dependence.

Treatment is typically antifungal, starting with topical agents such as selenium sulfide shampoo, ketoconazole, or zinc pyrithione preparations. For extensive, recurrent, or refractory disease, systemic therapy with an oral antifungal such as fluconazole or itraconazole may be recommended. Recurrence is common, and some patients require maintenance or repeated treatment courses.

In medical literature, furfuraceous describes bran-like scaling observed in pityriasis versicolor and other dermatologic conditions. The term furfur thus links a historical descriptor to a modern fungal pathogen and its clinical manifestations.