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.

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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.