Objectives: Nannizzia (N.) incurvata (formerly Microsporum incurvatum) represents a geophilic dermatophyte which has been previously classified as belonging to the species complex of N. gypsea (formerly Microsporum gypseum). According to the new taxonomy of dermatophytes, N. incurvata should be considered as an own species. Patients: A 42 years old Vietnamese female from Saxony, Germany, suffered from a burning tinea corporis superficialis of the right buttock after she has been returned from a 2-weeks-visit to her homeland Vietnam. From skin scrapings of the centrifugal lesions, N. incurvata was grown on Sabouraud´s dextrose agar. Family members were not affected. There was no approvement after treatment by clotrimazole+ betamethasone dipropionate ointment, ciclopirox olamine cream, and mometason furoate. After change to ciclopirox olamine cream monotherapy twice daily for 4 weeks, the tinea corporis healed. 
A 6 years old Cambodian boy living near to the river Mekong (water and forest region) at a village with contact to chicken, dogs, and cattle suffered from tinea faciei and tinea corporis. The members of the family were not affected. The disease started at an age of 4. Initial lesion was on the scalp, later extended to the face. Symptoms of the favus-like tinea capitis and tinea faciei were erythema, scaly patches with areas of alopecia, but no pustules. Main complains were pruritus and alopecia. The kid was treated first by paediatrician for 12 weeks with griseofulvin 250 mg once daily, but without improvement. Hepatitis B and C and HIV test were negative. From skin scrapings, also N. incurvata was grown on Sabouraud´s dextrose agar. Later on, at the Department of Dermatology in Phnom Penh, Cambodia, the boy was treated with oral terbinafine 125 mg daily, topical miconazole, ketoconazole shampoo, oral cetirizine, and multivitamin preparations. The symptoms improved after 2 weeks of treatment. Treatment was continued for altogether one month. Mycological diagnostics: The Blancophor® preparations from skin scrapings from scalp and buttocks were positive for both patients. Cultivation of the samples revealed the growth of N. incurvata which was confirmed by macromorphological and microscopic features. For confirmation of the species identification, the isolates were subject of sequencing of ITS (internal transcribed spacer) region of the rDNA, and additional of the „Translation Elongation Factor 1 α“ (TEF 1 α) gene. Sequencing of the ITS region showed 100 % accordance with the sequence of N. incurvata deposited at the NCBI database under the accession number MF415405. Until now, there is no N. incurvata sequence of the TEF 1 α gene available at all of the databases worldwide. For this reason, no identification based on TEF 1 α gene was possible. The phylogenetic analysis of the strains – the dendrogram of fungal strains – based on ITS region demonstrated the genetic differences between N. incurvata and the close related N. gypsea and N. fulvum. In contrast, sequencing of the TEF 1 α gene did not allow any discrimination between N. incurvata and N. gypsea. ITS-sequences of both here isolated strains will be deposited at the NCBI, the ISHAM ITS Database, and at the Fungal MLST Database. Conclusion: N. incurvata is a rare geophilic dermatophyte which has been described in Sri Lanka and Vietnam until now. This is the first isolation of N. incurvata in Cambodia, and the first description of favus in a child due to this dermatophyte.

Nannizzia incurvata as rare cause of favus and tinea corporis in Cambodia and Vietnam