A Special Tinea Nigra Caused by Curvularia lunata: Case Report and Literature Review

Tinea Nigra: Clinical and Diagnostic Guidance

Tinea nigra is a rare superficial fungal infection characterized by asymptomatic, unilateral, well-defined brown to black macules predominantly affecting the palms and soles. Diagnosis is often challenging due to its rarity and resemblance to other pigmented lesions. This report presents a clinical case, a diagnostic algorithm, and treatment recommendations, emphasizing the role of thorough examination and questioning. We describe the case of a 64-year-old woman of Amerindian (Maya) heritage from Yucatan, Mexico, who presented with a three-month history of a slowly growing dark spot on her left palm. The lesion was asymptomatic, non-scaling, and non-palpable. Palmar skin scrapings, prepared with KOH, revealed pigmented yeast and hyphae, leading to a diagnosis of tinea nigra. Following treatment with topical ketoconazole, the patient's lesions completely resolved at the one-month follow-up. The cultivation of scales confirmed the presence of Hortaea werneckii. Our findings highlight the importance of considering tinea nigra in the differential diagnosis of pigmented lesions on acral surfaces. We propose a diagnostic algorithm to aid healthcare professionals in recognizing this uncommon condition and recommend treatment protocols that effectively resolve the infection within two weeks. This case underscores the necessity for increased awareness and accurate diagnosis of tinea nigra, particularly in non-endemic regions.

The Epidemiology of Tinea Capitis in Guangxi Province, China

The aim of this study was to analyze the epidemiological characteristics and pathogen spectrum of tinea capitis in Guangxi, southern China. A multicenter prospective descriptive study was conducted in 8 hospitals across Guangxi. From January 2019 to July 2022, one hundred seventy-one (171) patients diagnosed with tinea capitis were included. Demographic data, risk factors, and fungal data were collected. If necessary, species were further identified by morphological or molecular sequencing in the central laboratory. Of the 171 cases of tinea capitis, 74.3% occurred in patients aged 2-8 years. Children with tinea capitis were mainly boys (59.6%) and were more likely than adults to have a history of animal contact (44.2% vs. 33.3%) and zoophilic dermatophyte infection (76.9% vs. 46.7%, P = 0.008). The adults were mainly female (53%) and were more likely than children to have a history of infection with anthropophilic organisms (53.3% vs. 18.9%). The causative agents of tinea capitis in Guangxi were diverse, and the most common pathogen was Microsporum canis (M. cani, n = 98, 62%), followed by Trichophyton mentagrophytes (T. mentagrophytes n = 18, 11.4%) and Trichophyton tonsurans (T. tonsurans n = 12, 7.6%). In addition, tinea capitis caused by Nannizzia incurvata (N. incurvata) and Trichophyton verrucosum (T. verrucosum) was detected in the study. Notably, the proportion of patients with kerion in the study was 41.5% (n = 71), and most of those patients were children (n = 68), especially neglected children living in the rural mountainous areas of Guangxi, where they were unable to receive timely diagnosis and appropriate treatment. In conclusion, the causative agents of tinea capitis in Guangxi, South China, are diverse, and the incidence of kerion is high, indicating that diagnosis and treatment modalities in the region remain grossly inadequate. Clinicians and policy-makers should collaborate to adopt public health strategies to control the disease.

Surgery plus photodynamic therapy for a diabetic patient with cutaneous infectious granuloma caused by Curvularia lunata

Curvularia lunata (C. lunata) can be easily found in environment and plants and rarely causes human infections. Antifungal agents have been the primary approach to treat such infections; however, adverse hepatotoxic reactions may require discontinuation of the long-term use of antifungal agents in patients with pre-existing liver diseases. New therapeutic approaches are thus needed to cope with these circumstances. Here, we report a 66-year-old diabetic female patient, suffering from a rapidly growing lesion on the nose for 2 months. The patient was diagnosed with cutaneous fungal infection caused by C. lunata, which was based on mycological study and ITS sequencing. The lesion was completely disappeared after a combination of surgery and 3 times of photodynamic therapy (PDT) with 5-aminolevulinic acid (ALA) at 9- day intervals. The patient did not receive any antifungal agents during the treatment. There was no recurrence at 6-month fellow-up. In the following in vitro study, C. Lunata growth was significantly inhibited by ALA-PDT treatment. Therapeutic success in this patent suggests that the ALA-PDT method could be a promising treatment for cutaneous fungal infection caused by C. Lunata and others.

Fungal Rhinosinusitis Caused by a Curvularia sp. Infection in a Female Sumatran Orangutan: A Case Report

Mycotic nasal cavity and paranasal sinus infections in non-human primates (NHPs) are relatively uncommon diseases of the upper respiratory tract. This case study describes the clinical and pathological features as well as the diagnostic techniques and interventions applied to treat the associated disease. A 23-year-old primiparous female Sumatran orangutan residing at Perth Zoo in Western Australia developed intermittent episodes of right-sided epistaxis. An ulcerative nasal mass was identified from a diagnostic endoscopy. The mass was initially biopsied and showed the morphological characteristics of a dematiaceous fungal organism upon a histological examination. There were prominent mucosal and submucosal granulomatous infiltrates containing histocytes, giant cells, and lymphocytes admixed with fewer numbers of neutrophils and eosinophils surrounding the fungal organism. The organism was identified as Curvularia sp. by the fungal characteristics associated with the histopathology, culture growth, and PCR analysis. The mass was subsequently removed with endoscopic sinus surgery (ESS) and the orangutan was medically treated with itraconazole for several months. The recovery was uneventful and the orangutan returned to full health.

Experimental Phaeohyphomycosis of Curvularia lunata

Originally considered to be a plant pathogen, reports of phaeohyphomycosis due to Curvularia lunata (C. lunata) in animals and humans are increasing. However, studies on the pathogenesis, virulence, and epidemiology of C. lunata have rarely been discussed. In the present study, BALB/c mice were experimentally inoculated with C. lunata suspension by different routes and the course of infection was evaluated. In addition, the in vitro antifungal susceptibility of C. lunata against six commonly used antifungals was evaluated using the microdilution method. Inoculation resulted in skin lesions in animals inoculated intraperitonially and subcutaneously. Infection was confirmed by both mycological and histopathologic examination. C. lunata spores and hyphae were detected in the histopathologic sections stained with hexamine silver staining. In addition, voriconazole (VRC) demonstrated greater activity against C. lunata when compared to the other antifungals, whereas fluconazole (FLC) was the least active antifungal with a minimum inhibitory concentration (MIC) range of 8–16 μg/mL. Further studies are necessary to understand the pathogenicity of C. lunata and uncover the mystery of this fungus.