Tinea nigra is a type of dermatomycosis. A dermatomycosis is a fungal infection of the skin. Tinea nigra affects the outermost layer of skin (called the stratum corneum). Tinea nigra causes a black or brown patch on the skin. Although a patch of tinea nigra may be mistaken for the more serious skin discolorations of melanoma, tinea nigra is actually a very benign condition that often causes no symptoms apart from its appearance.
Tinea nigra is caused by a fungus called hortaea werneckii. The fungus lives in rotting wood, soil, compost or sewage. You may contract the fungus if you are around any of these materials and you suffer an injury that involves a break in the skin.
Individuals more likely to develop tinea nigra are:
• Young adults
• Living or traveling in tropical or subtropical areas, such as:
• South Africa
• Puerto Rico
• Coastal areas along the Southeastern seaboard of the United States
Tinea nigra causes a brownish-black patch on the skin. The area tends to expand over time, has an irregular shape, and often sports a darker border. Sometimes the area is itchy or scaly. Patches usually affect the palms of the hands or soles of the feet. Occasionally, patches may appear on the neck or trunk.
Your doctor will ask about your symptoms, medical history and perform a physical exam. You may need to see a dermatologist for testing, diagnosis, and treatment of this condition. Tinea nigra is diagnosed by scraping a small sample of the affected skin. The sample is cultured in a laboratory and examined under a microscope, where the fungi can be identified.
Talk with your doctor about the best treatment plan for you. Tinea nigra is usually treated with topical medications that can be applied to the affected area of skin, such as:
• Whitfield’s Ointment
• 2% Miconazole cream
• 2% Ketoconazole cream
• 5-10% Salicylic acid ointment
To help reduce your chance of getting tinea nigra, take the following steps:
• Use care when traveling in areas where tinea nigra may be contracted.
• Avoid contact with potentially infected material, such as rotting wood, dirt, sewage, or compost.