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26 Cards in this Set
- Front
- Back
Define superficial mycoses
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Infections caused by fungi that colonize the keratinized outermost layers of the skin, hair, and nails. Infections are generally asymptomatic, nondestructive, and stimulate little or no host immune response
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What causes Pityriasis versicolor
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Malassezia furfur infection
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What is the clinical presentation of Pityriasis versicolor
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Hypo or hyper pigmented macules, usually on chest, shoulders, upper trunk, arm, neck; irregular patches, may be scaley
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How is Pityriasis versicolor diagnosed
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Microscopic ID of spaghetti and meatballs (yeast and hyphae) in epidermal scales treated with 10% KOH
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What is the treatment for Pityriasis versicolor
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Improved hygiene plus topical azoles or selenium sulfide shampoo
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What causes Tinea nigra
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Infection by Hortaea werneckii, formerly Exophiala werneckii
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What is the clinical presentation of Tinea nigra
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Single pigmented dark mass on palm or sole
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What is white piedra
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A superficial infection of hair (groin and axillae) caused by yeastlike fungi, Trichosporon species
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What does microscopic exam of White piedra show
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Budding yeast cells, hyphal elements, and arthroconidia
Culture infected hair on Sabouraud's without cycloheximide |
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What is black piedra
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An uncommon superficial infection of hair (usually on scalp) caused by Piedraia hortae
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What are the three common dermatophytes
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Epidermophyton, Microsporum, Trichophyton
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The most common dermatophytoses worldwide are caused by what
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Trichophyton rubrum and Trichophyton mentagrophytes
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How are dermatophytoses transmitted
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Direct from arthroconidia or hyphae
Indirect from infected desquamated skin or hair |
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What are the six common Dermatophytic tinea infections
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Tinea capitis (head)
Tinea pedia (foot) Tinea cruris (groin) Tinea barbae (beard) Tinea corporus (body) Tinea unguium=onychomycosis (nails) |
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How are dermatophytes infections diagnosed
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Dissolve skin scrapings in KOH to digest keratin. Microscopic exam will reveal branched hyphae
Direct exam of hair and skin with Wood's light (UV 365nm). Certain species of Microsporum will fluoresce a brilliant green |
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How are dermatophyte infections affecting skin treated
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With topical agents (imidazoles, terbinafine, haloprogin) or Whitfield's ointment
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What are some general characteristics of subcutaneous mycoses
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Usually introduced by trauma; fungi usually found in soil; Involve dermis, subcutaneous tissue, and bone
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What fungus is characterized as thermally dimorphic, commonly found in soil and on plants. Following a prick by a thorn contaminated with it, a subcutaneous nodule gradually appears. This nodule becomes necrotic and ulcerates. The ulcer heals, but new nodules pop up nearby and along the lymphatic tracts up the arm.
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Sporothrix schenkii
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How is Sporothrix schenckii diagnosed
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Microscopic exam reveals yeast cells that reproduce by budding. Yeast at 37C, branching hyphae at 25C
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How is Sporothrix schenkii infection treated
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Potassium iodide classically
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What infection is defined by Chronic fungal cutaneous and subcutaneous fungal infections distinguished by slow-growing verrucous nodules and plaques, most often caused by dematiaceous (pigmented) fungi such as Phialophora and Cladosporium
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Chromoblastomycosis
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What fungus has muriform cells (copper bodies), causes increase of melanin in cell walls, and is distinguished by slow-growing verrucous nodels and cauliflower excrescence
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Chromoblastomycosis
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What is the treatment for Chromoblastomycosis
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Itraconazole; flucytosine added in unresponsive cases
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What disease is defined by chronic subcutaneous fungal infections caused by pigmented (dematiaceous) fungi which appear in tissue as irregular hyphae (rather than the sclerotic muriform cells of chromoblastomycosis)
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Subcutaneous Phaeohyphomycosis
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What disease is defined by a localized, chronic, invasive, granulomatous, fungal infection, characterized by multiple large granulomas and abscesses containing funga granules/grains and hyphae. Extent of damage may be deforming with irreversible destruction of muscle, bone, and fascia. Abscess drainage (including granules) is external through the skin
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Eumycotic mycetoma
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Madura foot is a manifestation of what
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Infiltration of tarsals and metatarsals in advance Eumycotic Mycetoma
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