Tinea nigra On the Web
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. ; Associate Editor(s)-in-Chief: Kiran Singh, M.D. 
Tinea nigra (also known as "superficial phaeohyphomycosis," and "Tinea nigra palmaris et plantaris") is a superficial fungal infection that causes dark brown to black painless patches on the palms of the hands and the soles of the feet.:311
This infection is caused by the fungus formerly classified as Exophiala werneckii but more recently classified as Hortaea werneckii.
The causative organism has also been described as Phaeoannellomyces werneckii.
Diagnosis of tinea nigra causing fungus is made on microscopic examination of skin scrapings, mixed with potassium hydroxide (KOH). The KOH lyses the nonfungal debris.
Tinea nigra must be differentiated from other diseases presenting with an erythmatous, scaly, annular and pruritic rash. The differentials include the following:
|Name of superficial infection||Clinical presentation||Extension to hair follicle||Fungus(i)||Systemic disease||KOH preparations||Morphology in tissue sections|
|Tinea or ringworm||Round lesions with scaly border, accompanied by pruritis and burning||Yes; when suppurative known as kerion, when chronic known as Majocchi's granuloma||Dermatophytes (Epidermophyton spp., Trichophyton spp., Microsporum spp.)||Very rare but can invade the dermis and soft tissues, causing mycetomas||Hyphae with or without septations||Hyphae cannot be visualized in the keratin with H&E, special stains are needed|
|Tinea versicolor||Hypo and hyperpigmentation in patients with oily and sweaty skin, fine scales when scratching||Yes, known as Pityrosporum folliculits||Malassezia spp.||Systemic infections may occur in premature neonates receiving parenteral nutrition and in other immunosuppressed hosts||Yeasts and hyphae (“spaghetti and meat balls”)||Faintly basophilic hyphae in the stratum corneum|
|Tinea nigra||Brown to black macule, usually on palms, with some scaling||No||Phaeoannellomyces werneckii||Not described||Darkly pigmented, septated, and branching hyphae||Pigmented hyphae in the stratum corneum|
|White piedra||Creamy-white, small, soft nodules in hair shafts||No||Trichosporon spp.||Immunosuppressed patients may have lung infiltrates, renal involvement, and fungemia||Septate hyphae perpendicular to hair shaft||Not used for diagnosis|
|Black piedra||Hard dark nodules in hair shafts||No||Piedraia hortae||Not described||Collections of crescent ascospores surrounded by pigmented hyphae||Not used for diagnosis|
|Superficial candidiasis||Intertrigo, chronic paronychia, onychodystrophy, cheilitis||Yes||Candida spp.||Yes, particularly in patients with AIDS and depending on the level of immunosuppression||Yeasts, pseudohyphae may be observed||Fungal elements may be seen through the biopsy, vascular invasion must be determined|
Treatment consists of topical application of dandruff shampoo, which contains selenium sulfide, over the skin. Topical antifungal imidazoles may also be used, such as Ketoconazole. This is the same treatment plan for tinea or pityriasis versicolor.
- ↑ 1.0 1.1 Rapini, Ronald P.; Bolognia, Jean L.; Jorizzo, Joseph L. (2007). Dermatology: 2-Volume Set. St. Louis: Mosby. pp. Chapter 76. ISBN 1-4160-2999-0.
- ↑ James, William D.; Berger, Timothy G.; et al. (2006). Andrews' Diseases of the Skin: clinical Dermatology. Saunders Elsevier. ISBN 0-7216-2921-0.
- ↑ Murray, Patrick R.; Rosenthal, Ken S.; Pfaller, Michael A. (2005). Medical Microbiology (5th ed.). Elsevier Mosby.
- ↑ Pegas JR, Criado PR, Lucena SK, de Oliveira MA (2003). "Tinea nigra: report of two cases in infants". Pediatric dermatology. 20 (4): 315–7. doi:10.1046/j.1525-1470.2003.20408.x. PMID 12869152.
- ↑ 5.0 5.1 Gladwin, Mark; Trattler, Bill. Clinical Microbiology (4th ed.). p. 196.
- ↑ 6.00 6.01 6.02 6.03 6.04 6.05 6.06 6.07 6.08 6.09 6.10 6.11 6.12 6.13 6.14 6.15 6.16 6.17 6.18 6.19 6.20 6.21 6.22 6.23 6.24 6.25 6.26 6.27 6.28 6.29 6.30 6.31 6.32 6.33 6.34 6.35 6.36 6.37 6.38 6.39 6.40 6.41 6.42 6.43 6.44 6.45 6.46 6.47 6.48 6.49 6.50 6.51 6.52 6.53 6.54 6.55 6.56 6.57 6.58 6.59 6.60 6.61 "Dermatology Atlas".