Tinea nigra - Clinicals, Diagnosis, and Management

Dermatology

Clinicals - History

Fact Explanation
Rash Tinea nigra is a chronic and asymptomatic
dermatomycosis of the stratum corneum of skin caused by Exophiala werneckii or Cladosporium werneckii (also named as Phaeoannellomyces werneckii). Infection occurs by an inoculation from contaminated soil, sewage, wood, or compost. A trauma can innoculate the fungi.
This fungi can produce melanin which results in a macule. It is a well-demarcated brown-black macular lesions which usually occur on the palmar aspects of hands and occasionally the plantar and other surfaces of the skin. The lesion is usually single, not itching and painless.
Rash
Tinea nigra is a chronic and asymptomatic
dermatomycosis of the stratum corneum of skin caused by Exophiala werneckii or Cladosporium werneckii (also named as Phaeoannellomyces werneckii). Infection occurs by an inoculation from contaminated soil, sewage, wood, or compost. A trauma can innoculate the fungi.
This fungi can produce melanin which results in a macule. It is a well-demarcated brown-black macular lesions which usually occur on the palmar aspects of hands and occasionally the plantar and other surfaces of the skin. The lesion is usually single, not itching and painless.
No redness Lesions are usually non-inflammatory. No redness
Lesions are usually non-inflammatory.

Clinicals - Examination

Fact Explanation
Macular lesion These are usually well-demarcated brown-black (hyperpigmented) macular lesions.They presents as a solitary lesion, although more than one lesion can be present. The typical location is the palmar or plantar surfaces of the hands or feet. Rarely, some cases has been presented over the neck and chest. The shape may appear ovoid, round, or irregular. Macular lesion
These are usually well-demarcated brown-black (hyperpigmented) macular lesions.They presents as a solitary lesion, although more than one lesion can be present. The typical location is the palmar or plantar surfaces of the hands or feet. Rarely, some cases has been presented over the neck and chest. The shape may appear ovoid, round, or irregular.
No erythema Tinea lesions are non-inflammatory. No erythema
Tinea lesions are non-inflammatory.
No scaling Outer layer of the epidermis (Stratum corneum) is not affected by tinea infection. Therefore scaling does not happen. No scaling
Outer layer of the epidermis (Stratum corneum) is not affected by tinea infection. Therefore scaling does not happen.
Dermoscopy findings Darkened irregular puntiform pigmentation is characteristic for tinea nigra. These pigmentation does not follow the furrows and ridges normally observed in the skin. Dermoscopy findings
Darkened irregular puntiform pigmentation is characteristic for tinea nigra. These pigmentation does not follow the furrows and ridges normally observed in the skin.

Investigations - Diagnosis

Fact Explanation
Microscopic examination Scrapings taken from the edge of the scaly lesion are microscopically examined after being treated with 20% pottasium hydroxide. It shows mycelium (a group of branched filaments or hyphae). The hyphae are septate, branched and have dark pigmentation in walls. Microscopic examination
Scrapings taken from the edge of the scaly lesion are microscopically examined after being treated with 20% pottasium hydroxide. It shows mycelium (a group of branched filaments or hyphae). The hyphae are septate, branched and have dark pigmentation in walls.
Culture Culture grows black colonies of Exophiala werneckii or Cladosporium werneckii on sabouraud agar within a week. The colonies are shiny, humid and black. Culture
Culture grows black colonies of Exophiala werneckii or Cladosporium werneckii on sabouraud agar within a week. The colonies are shiny, humid and black.
Biopsy Skin biopsy is not essential in diagnosing the disease. Histologically, Tinea nigra shows hyperkeratosis and mild acanthosis. Biopsy
Skin biopsy is not essential in diagnosing the disease. Histologically, Tinea nigra shows hyperkeratosis and mild acanthosis.
Dermoscopic examination Darkened irregular puntiform pigmentation is characteristic for tinea nigra. These pigmentation does not follow the furrows and ridges normally observed in the skin. Dermoscopic examination
Darkened irregular puntiform pigmentation is characteristic for tinea nigra. These pigmentation does not follow the furrows and ridges normally observed in the skin.

Management - Supportive

Fact Explanation
Parent education and preventive measures Good hygienic measures such as regular hand washing is a main preventive method. Patient should be educated to avoid sharing things such as clothing with others. Good skin hygiene, good nail hygiene are also important. Prolonged wetting of skin and feet should be avoided. Parent education and preventive measures
Good hygienic measures such as regular hand washing is a main preventive method. Patient should be educated to avoid sharing things such as clothing with others. Good skin hygiene, good nail hygiene are also important. Prolonged wetting of skin and feet should be avoided.

Management - Specific

Fact Explanation
Topical antifungal agents The creams are applied to the affected area twice daily for two to four weeks, including a margin of several centimetres of normal skin. The treatment is continued for one or two weeks after the last visible rash has cleared. Repeated treatment is often necessary. Ciclopirox olamine is found to be more effective. Isoconazole, terbinafine, butenafine and amorolfine oxiconazole are the other effective topical antifungals.
Systemic antifungals are not needed because topical antifungals have been successful.
Topical antifungal agents
The creams are applied to the affected area twice daily for two to four weeks, including a margin of several centimetres of normal skin. The treatment is continued for one or two weeks after the last visible rash has cleared. Repeated treatment is often necessary. Ciclopirox olamine is found to be more effective. Isoconazole, terbinafine, butenafine and amorolfine oxiconazole are the other effective topical antifungals.
Systemic antifungals are not needed because topical antifungals have been successful.

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