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Tinea nigra - Skin in Child
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Tinea nigra - Skin in Child

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Contributors: Nianda Clouden Reid MD, MBA, Brian Poligone MD, Jeffrey D. Bernhard MD, Belinda Tan MD, PhD, Sarah Stein MD, Karen Wiss MD, Sheila Galbraith MD, Craig N. Burkhart MD, Dean Morrell MD, Lynn Garfunkel MD, Nancy Esterly MD
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Synopsis

Tinea nigra is a dermatomycosis caused by Hortaea werneckii, formerly known as Phaeoannellomyces werneckii, Exophiala werneckii, and Cladosporium werneckii. There have also been cases of tinea nigra due to Stenella araguata in South America. It presents as a hyperpigmented macule(s), usually on the palm or sole. Other areas of the body can also be affected.

After contamination from an infected source (eg, soil, sand, waste, or wood), the mycosis infects the stratum corneum, resulting in a dark-colored macule caused by the accumulation of a melanin-like substance in the fungus. The fungus adheres to the skin because of its ability to survive high-salinity environments. The incubation period is typically 2 to 7 weeks; however, a study has shown the incubation period to range from a few weeks to 20 years.

Tinea nigra is an uncommon finding in the US, with most cases found near coastal areas or in the southern US. It is more commonly found in tropical regions of Central and South America, Africa, Southeast Asia, and Australia. The most affected populations are children and adolescents (children are more prone to exposure to the fungus); however, persons of any age may be affected. There is a female-to-male incidence of 3:1. Tinea nigra seems to appear less often in patients with more deeply pigmented skin; however, this may be due to reduced recognition of the disease. Risk factors include living in or travel to tropical areas where the organism is common. Risk is increased in patients with excessive sweating.

Signs – Usually asymptomatic, well-demarcated lesion of variable size and irregular shape (between 1 and 5 cm). There is often a single brown or black macule on the palmar or plantar skin, although there may be multiple spots; it occurs rarely on the neck or trunk. The lesion may rarely appear scaly. Many times the lesion is misdiagnosed as malignant melanoma.

Symptoms – Tinea nigra usually lacks erythema or induration and is rarely pruritic. It is usually a benign condition that clears within 2 weeks of treatment with an antifungal agent and rarely reoccurs.

Immunocompromised Patient Considerations
The fungi involved in causing infections of tinea nigra can lead to serious infections in immunocompromised patients. There is a risk of disseminated disease from superficial cutaneous fungal infections noted in transplant patients.

Codes

ICD10CM:
B36.1 – Tinea nigra

SNOMEDCT:
186289000 – Tinea nigra

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Diagnostic Pearls

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Differential Diagnosis & Pitfalls

  • Intracorneal hemorrhage
  • Melanoma – Presents with irregular borders, color of different shades, expanding diameter; easily differentiated from tinea nigra using dermatoscopy. No hyphae found on KOH scrapings.
  • Junctional nevus – Mole found on the border of epidermis and dermis; no hyphae found on KOH scrapings.
  • Post-inflammatory pigmentation – Sequelae of inflammatory skin condition; evidence of inflammatory condition prior to hyperpigmentation.

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Therapy

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References

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Last Updated: 01/22/2014
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Tinea nigra - Skin in Child
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Tinea nigra : Hyperpigmented macule, Hyperpigmented patch, Irregular configuration, Palm, Plantar foot
Clinical image of Tinea nigra
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