Cutaneous fungal microbiome: Malassezia yeasts in seborrheic dermatitis scalp in a randomized, comparative and therapeutic trial

ABSTRACT

Malassezia spp in skin microbiome scalp has been implicated in seborrheic dermatitis pathogenesis. Thus, treatment based in antifungal combined to topical keratolitic agents have been indicated as well as oral isotretinoin as it reduces the sebum production, glandular's size and possesses anti-inflammatory properties. This randomized, comparative and therapeutic trial aimed toper form the genotypic identification of Malassezia species before and after low-dose oral isotretinoin or topical antifungal treatments for moderate to severe seborrhea and/or seborrheic dermatitis on scalp. Scales and sebum of the scalp were seeded in the middle of modified Dixon and incubated at 32°C. For genotypic identification polymerase chain reaction primers for the ITS and D1/D2 ribossomal DNA were used and followed by samples sequencing. The procedure was conducted before and after therapeutic and randomized intervention for moderate to severe seborrhea/seborrheic dermatitis on the scalp, including oral isotretinoin, 10 mg, every other day and anti-seborrheic shampoo (piroctone olamine), over six months. The M. globosa and M. restricta were the most frequent species isolated on the scalp before and after both treatments. Other non-Malassezia species were also identified. The Malassezia spp. were maintained in the scalp after both treatments that were equally effective for the control of seborrhea/seborrheic dermatitis clinical signs.

KEYWORDS:

• Malassezia
• oral isotretinoin
• piroctone olamine
• polymerase chain reaction
• seborrheic dermatitis

Disclosure of potential conflicts of interest

No potential conflicts of interest were disclosed.

Acknowledgments

The authors thank Germed Pharma (Campinas, SP, Brazil) for the donation of oral isotretinoin, and L'Oréal Brasil (Rio de Janeiro, RJ, Brazil) and Galderma Brasil (Hortolândia, SP, Brazil) for donations of topical products. The authors thank Fundacão de Amparo à Pesquisa do Estado de São Paulo – FAPESP-Brazil (No 2010/51049-1) and Dr Olga Gompertz and Dr Arnaldo Colombo for providing the laboratory to develop this study.

Funding

Fundação de Amparo à Pesquisa do Estado de São Paulo (São Paulo Research Foundation [FAPESP]), Brazil (no. 2010/51049-1).