B36.1

Clinical Causes: Infection with the fungus Hortaea werneckii, which thrives in warm, humid environments. Exposure to contaminated soil or plant material where the fungus resides. Contact with surfaces or objects contaminated with the fungus, such as soil, wood, or plant debris. Poor skin hygiene, which can facilitate fungal colonization. Potential increased risk in individuals with compromised skin barrier or immune system.

Key Symptoms: Asymptomatic dark brown or black patches on the palms or soles. Lesions may be oval, irregular, or well-defined in shape. Surface of the patches may be smooth or slightly rough. Rarely causes itching or discomfort. Lesions typically do not spread beyond the initial area.

Diagnosis Path: Diagnosis of Tinea nigra usually involves a thorough physical examination of the skin lesion. Dermatologists may perform skin scrapings or biopsies to identify the fungal elements under microscopy. Wood's lamp examination can sometimes assist in visualization, although it is not specific. Laboratory tests, including culture, are vital to confirm the presence of Hortaea werneckii. Differentiating Tinea nigra from other pigmented skin conditions—such as melanoma or post-inflammatory hyperpigmentation—is crucial for appropriate management.

Treatment Protocols: Treatment options for Tinea nigra typically involve topical antifungal medications, which are applied directly to the affected areas. Common treatments include azole-based creams or solutions. In rare cases, oral antifungal agents might be prescribed if topical treatment is ineffective or extensive infection occurs. Maintaining good skin hygiene and avoiding environmental sources of the fungus can help prevent recurrence. Lesions generally resolve with proper antifungal therapy, leaving minimal scarring or pigmentation changes.