DefinitionTinea nigra is an infection of the skin. It affects the outermost layer of skin. The infection will cause a black or brown patch on the skin. Except for the dark patch, tinea nigra is a harmless condition.Tinea nigra usually affect the palms of the hands or soles of the feet. It may also appear on the neck or trunk.
|Cross-Section of Skin|
|Tinea nigra affects the topmost layer of skin.|
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CausesTinea nigra is caused by a fungus. The type of fungus that causes this infection is most often found in rotting wood, soil, compost, or sewage. The fungus may enter your body through a break in your skin.
Risk FactorsYou are more likely to develop tinea nigra if you have been living or traveling in tropical or subtropical areas, such as:
- South Africa
- Puerto Rico
- Coastal areas along the southeastern United States
SymptomsTinea nigra causes a brownish-black patch on the skin that:
- Has an irregular shape with a darker border
- May be itchy or scaly
- Tends to expand over time
DiagnosisYour doctor will ask about your symptoms and medical history. A physical exam will be done. You may need to see a skin specialist for tests, diagnosis, and treatment.Tinea nigra is diagnosed by scraping a small sample of the affected skin. The sample is examined under a microscope.
TreatmentTinea nigra is usually treated with an antifungal medication. The medication is placed on the skin as creams or ointments.
PreventionTo help reduce your chance of tinea nigra:
- Use care when traveling in high-risk areas.
- Avoid contact with potentially infected material, such as rotting wood, dirt, sewage, or compost.
- If you must work with any of the materials listed above, take the proper safety steps. Wear gloves and other protective gear.
American Academy of Dermatology
The College of Family Physicians of Canada
Gupta AK. Tinea corporis, tinea cruris, tinea nigra, and piedra. Dermatol Clin. 2003;21:395-400.
Habif TP. Clinical Dermatology. 4th ed. St. Louis: Mosby; 2004.
Mandel GL, Bennett JE, et al. (eds). Principles and Practice of Infectious Diseases. 6th ed. Philadelphia, PA: Elsevier, Inc.; 2005.
Tropical travel. American Academy of Dermatology website. Available at: http://www.aad.org/media-resources/stats-and-facts/prevention-and-care/tropical-travel. Accessed December 7, 2012.
- Reviewer: David L. Horn, MD, FACP
- Review Date: 12/2014
- Update Date: 12/20/2014