Tinea nigra by Hortaea werneckii, a report of 22 cases from Mexico

Abstract

Tinea nigra is a superficial mycosis caused by Hortaea werneckii. It is an infrequent asymptomatic infection that affects human palms and soles, and is mostly observed in tropical countries. We evaluate retrospectively twenty-two confirmed cases of tinea nigra from a total of eleven yr (1997-2007) and discuss the epidemiology, clinical features and treatment of this disease. In twelve cases, adults were involved, in 10, children. In nineteen cases the disorder was located on palms of hands and in three on soles of feet. In all cases, the obtained isolates were morphologically identified as Hortaea werneckii and the identification of ten isolates was retrospectively confirmed with the help of sequences of the internal transcribed spacer regions of the ribosomal DNA. The patients received topical treatment with Whitfield ointment, ketoconazole, bifonazole, or terbinafine. Treatment with keratolytic agents and topical antifungals was effective.

Keywords: Hortaea werneckii; keratolysis; melanized fungi; superficial mycosis; tinea nigra; tinea palmaris.

Fig. 1.

Map showing the distribution of cases analysed.

Fig. 2.

A. Extensive tinea nigra palmaris (case 1; Table 1); B. Localized tinea nigra (case 9, CBS 122348; Table 1); C. Close-up of a pigmented macula (case 20, CBS 122342; Table 1); D. Tinea nigra plantaris, panoramic; E. Tinea nigra interdigital (case 13, CBS 123045; Table 1); F. Tinea nigra under dermatoscopy, multiple pigmented lesions; G. Direct examination of pigmented and septate hyphae (KOH, 40×); H. Direct examination of short filaments and multiple blastoconidia (KOH, 40×) (case 20, CBS 122342, Table 1).

Fig. 3.

Culture of Hortaea werneckii on SGA. Two phases: yeast-like phase with moist colonies, and filamentous colony (case 11, CBS 122344; Table 1).

Fig. 4.

Multiple blastoconidia with central septa (KOH, 40×). (case 20, CBS 122342; Table 1).