Definition

Tinea 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
skin layers cross section
Tinea nigra affects the topmost layer of skin.
Copyright © Nucleus Medical Media, Inc.

Causes

Tinea 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 Factors

You are more likely to develop tinea nigra if you have been living or traveling in tropical or subtropical areas, such as:

  • South Africa
  • Brazil
  • Panama
  • Cuba
  • Puerto Rico
  • Coastal areas along the southeastern United States

Symptoms

Tinea 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

A tinea nigra patch may be mistaken for a type of skin cancer. Talk to your doctor about any skin growth or changes.

Diagnosis

Your 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.

Treatment

Tinea nigra is usually treated with an antifungal medication. The medication is placed on the skin as creams or ointments.

Prevention

To 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.

Revision Information

  • American Academy of Dermatology

    http://www.aad.org

  • Dr. Fungus

    http://www.doctorfungus.org

  • Health Canada

    http://www.hc-sc.gc.ca

  • The College of Family Physicians of Canada

    http://www.cfpc.ca

  • 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.