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29 Cards in this Set
- Front
- Back
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Cause: black piedra
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Piedra hortae is a black monomorphic mold that produces a superficial
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Epidemiology: black piedra
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found in south america as normal human flora, in soil or in non-human mammals
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transmission: black piedra
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fomites
person to person non-human mammal to person |
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pathogenesis: black piedra
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infection of hairs of scalp forms mycelial and nodular swellings along axis of hair shafts
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Sx: black piedra
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gritty hard black encrustations of cemented hyphal cells from painless nodules
black dandruff |
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DX: black piedra
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KOH or PAS staining of cross sections of hairs show hard shafts with black, nodules containing asci with multiple ascospores
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tx: Black piedra
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selenium sulfide
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Cause: pityriasis (tinea) versicolor
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malassezia furfur is lipophilic dimorphic fungus that causes superficial mycotic infection of skin
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epidemiology: pityriasis (tinea) versicolor
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contaminated fomites
predisposing factors are use of lipid emusions, high cortisol levels incidence rates: 40 to 60% infections common btw adolescence and middle age and with genetic susceptibility |
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pathogenesis: pityriasis (tinea) versicolor
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lipophilic fungus feeds on skin oil and removes stratum corneum layer
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sx: pityriasis (tinea) versicolor
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lesions are red brownish, painless, hypo/hyper pigmented patches on skin of upper body of nonsuntanned individuals
suntanned/dark skinned individuals have pinkish white patches on skin of upper body itchy papules and pustules or atopic dermatitis on back and upper trunk |
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dx: pityriasis (tinea) versicolor
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KOH or PAS short stubby hyphae and globose budding in form of spaghetti and meatballs
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tx: pityriasis (tinea) versicolor
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ketoconazole
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cause: tinea negra
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Hortaea werneckii is black monomorphic mold that causes superficial mycosis of skin
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epidemiology: tinea negra
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-person to person/fomites
-mold feeds on stratum corneum layer of hands/feet resulting in squamous cell turnover of outer epithelium |
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sx: tinea negra
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solitary brownish-black, flat painless macules with deeper pigmentation form at advancing periphery
color of lesions: produced by black color of fungus |
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dx: tinea negra
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KOH or PAS staining of skin scrapings show multiple branched septate, dark pigmented hyphae and elongated budding cells
must be differentiated from malignant melanoma |
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tx: tinea negra
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miconazole
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cause: white piedra:
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trichosporon ovoides- white mold
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epidemiology white piedra
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-worldwide
-stagnant water and soil -normal flora of humans and other mammals |
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pathogenesis: white piedra
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white mycelial and nodular swellings along axis of hair shafts
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sx: white piedra
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soft white painless nodules form around cuticle of hair resulting in crusts on skin or hair of the head or genitals
color produced by white fungus |
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dx: white piedra
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koh or pas staining
hair shifts with hyaline septate hyphae broken up into arthrospores |
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tx: white piedra
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selenium sulfide
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cause: Otomycosis
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Aspergillus, Penicillium, Mucor, Rhizopus
infections of the outer ear |
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epidemiology: Otomycosis
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worldwide in soil,
infects humans and animals but they are not reservoirs |
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pathogenesis: Otomycosis
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accumulation of epithelial debris containing fungi and/or bacteria in EAC
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Dx: Otomycosis
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KOH reveal fragments of mycelium
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Tx: Otomycosis
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Ketoconazole
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