Bilateral tinea nigra in a temperate climate
Published Web Locationhttps://doi.org/10.5070/D35jf0b2wm
Bilateral tinea nigra in a temperate climate1. Federal University of Pelotas, Brazil. firstname.lastname@example.org
Hiram Larangeira de Almeida Jr1, Rodrigo Nelson Dallazem1, Leonardo Sundin dos Santos1, Simone Ávila da Silva Hallal2
Dermatology Online Journal 13 (3): 25
2. Laboratory for Microbiology, Unimed Pelotas, Brazil
Tinea nigra is a superficial mycosis associated with a dematiaceous fungus called Phaeoannellomyces werneckii. It is clinically characterized by asymptomatic non-scaly brown and black macules, the most common localization is the palmar region. Only one bilateral case occurring on the plantar skin and four palmar bilateral cases have been reported. We report the case of a 5-year-old boy presenting two hyperpigmented lesions with an irregular contour in both palmar regions, which appeared three months prior to presentation. Topical treatment with ketoconazole was effective.
Tinea nigra is a superficial mycosis that is associated with a dematiaceous fungus called Phaeoannellomyces werneckii [1, 2]. In general, it affects the skin of the palm and occasionally the soles [3, 4]. It is more common in tropical and subtropical climates, but has been reported seldom in regions of a temperate climate [5, 6]. Bilateral involvement is very rare . Clinically the infection presents as asymptomatic non-scaly brown or black macules [1, 2, 3, 5, 7].
A 5-year-old boy presented to the pediatric outpatient clinic with two irregularly shaped, hyperpigmented lesions on both palms; the onset was 3 months prior and gradual enlargement was noted. The patient lives in the city of Pelotas, which has a temperate climate. The family denied travel to subtropical or tropical areas of Brazil, contact with plants, or trauma in the involved areas. Skin examination showed a hyperpigmented macule on the right palm, measuring 3 x 2 cm and another on the left palm measuring 1.5 x 2.5 cm (Fig. 1). Direct mycological examination showed hyphae, some with melanin-like pigment (Fig. 2). The lesions cleared with topical ketoconazole.
|Figure 1||Figure 2|
|Figure 1. Irregular hyperpigmented lesions on both palmar regions|
Figure 2. Presence of hyphae on direct mycological examination, some of them with dark pigmentation
Tinea nigra is more common among young people. The most commonly affected area is the palmar region and occurrence on the soles is uncommon. In the literature, there is a description of one bilateral case occurring on the plantar skin and of four palmar bilateral cases [2, 4, 5]. The disease occurs most frequently in tropical and subtropical areas [1, 2, 3]. The differential diagnosis includes exogenous pigmentation, melanocytic lesions (lentigo, melanoma, phytophotodermatitis, fixed drug eruption), and bruising [1, 2, 4].
The diagnosis is clinical and can be confirmed with direct mycological examination after clarification with potassium hydroxide. Septate hyphae that are irregular and contain melanin-like pigment are observed ; the diagnosis may be confirmed by culture. Making the correct diagnosis is important because this prevents the performance of invasive biopsy if a melanocytic lesion is suspected [3, 7].
Topical antifungal therapy is effective; the use of imidazoles and terbinafine has been proved successful.
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