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29 Cards in this Set
- Front
- Back
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Superficial mycoses - def’n + egs |
Fungal diseases limited to outermost layer of skin + hair Pityriasis versicolor Tinea nigra Black piedra White piedra |
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Cutaneous mycoses/ Dermatophytoses - def’n + egs |
Fungal infections that extend to deeper into epidermis (skin), hair + nails Dermatophytosis - Ring/tinea worm of skin, hair + nails |
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Superficial mycosis: Tinea/ Pityriasis versicolor - etiology + clinical findings |
Aka Lotta | liver spot | shifting cloud Fungus - malassezia furfur aka pityrosporum orbiculare Decolourisation of skin - blotchy hypo/hyperpigmented macular itchy lesion scattered over trunk, neck + upper arm |
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Superficial mycosis: Tinea/ Pityriasis versicolor - lab dx + rx |
Dx - 1. direct microscopy of skin scales on KOH mount (🍝 appearance); 2. culture of infected skin scraping in SDA (fried 🍳 colonies + smear showing 🍼 shaped budding yeast cells) Rx - Ketaconazole |
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Superficial mycosis: Tinea nigra - etiology + clinical findings |
Fungus - exophiala/ hortaea werenckii Painless dark brown to black macular patches (due to melanin accumulation) on palm + soles (thickly keratinized) |
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Superficial mycosis: Tinea nigra - lab dx + rx |
Dx - (1) Microscopy of skin scrapping on KOH - brownish branched septate hyphae + budding cells (2) light - dark grey colonies on SDA Rx - Micanazole |
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Superficial mycosis: White piedra - etiology + clinical findings |
Tricosporum beigelii Irregular, soft, white or light brown nodules firmly adhering to axillary + pubic hair shafts |
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Superficial mycosis: White piedra - lab dx + rx |
Dx - creamy white, Urease +ve colonies on SDA Rx - remove hair & apply topical Imidazole or Amphotericin B lotion |
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Superficial mycosis: Black piedra - etiology + clinical findings |
Piedraia hortae Black hard nodules on scalp + beard hair shafts (YA + fams due to sharing combs) |
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Superficial mycosis: Black piedra - lab dx + rx |
Dx - dark reddish brown colonies w thick septate hyphae on SDA Rx - remove hair & apply topical Imidazole or Amphotericin B |
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Stain used for fungal morphology |
Lactophenol Cotton Blue (LPCB) stain: Lactic acid - preserves fungal structure Phenol - kills live organisms Glycerol - prevents drying Cotton Blue - imparts blue color to structures |
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Dermophytosis: Tinea Capitis (Ringworm of the Scalp) - etiological agents, types + rx |
microsporum audouinii, microsporum canis - circular bald patches w short/broken hair stubs within hair follicles (1) Non inflammatory- alopecia w mild scaling, black dot hairs (2) inflammatory - “kerion” , 🥵, scarring alopecia that looks bacterial (-ve KOH often) caused by M. canis Rx - systemic agents + steroids for Kerion for 6-12 wks |
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Dermophytosis: Tinea Corporis (Ringworm of the Body) - etiological agents + signs |
Microsporum canis, Trichophyton rubrum, M. audouinii, T. mentagrophytes Red circular pruritic patches w border and central scaling (healing from center) on non-hairy smooth skin |
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Dermophytosis: Tinea Cruris (Jock itch) - etiological agents + signs |
T. rubrum, T concentricum, T mentagrophytes, Epidermophyton floccosum Red scaly raised patches that may blister and ooze w redder edges + itching in groin, thigh skin folds or anus (perineum) |
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Dermophytosis: Tinea Pedis (Athlete’s foot) - etiological agents + signs |
T rubrum, T mentagrophytes, T concentricum, E floccosum Itching in soles and b/w toes (acute: red vesicular vs chronic: scaling + fissures) |
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Dermophytosis: Tinea Unguim (Nails) - etiological agents, signs + predisposing factors |
Discolored, lusture less nails thickened or crumbing distally T rubrum, T concentricum, T mentagrophytes, E floccosum Risk factors - manipedis w infected tools, minor skin/nail injuries, wearing closed footwear (moist skin for long time) + poor IS |
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Dermophytes: Trichophyton rubrum - lab dx |
SDA culture w chloramphenicol + chlorhexidine - white cottony surface Smear - piriform (🍐 -shaped) microconidia + ✏️-shaped macroconodia |
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Dermophytes: Epidermophyton floccosum- lab dx |
SDA culture w chloramphenicol + chlorhexidine - white yellow colonies Smear - macroconidia + club-shaped smooth walled-septate |
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Dermophytes: Microsporum canis- lab dx |
SDA culture w chloramphenicol + chlorhexidine- white to yellow dense cottony surface (bright yellow reverse pigment) Smear - macroconidia + spindle-shaped thick walled-septate |
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Dermophytosis - rx + prevention |
Rx - Remove infected/dead epithelium + apply antifungal Topical - micon- or clotrim- or econazole or terbinafine Oral - griseofulvin (4-6wk for skin; 1y for nail) Prevention - keep dry + avoid sources of infection |
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Dermophytes genera: Trichophyton - site of infection + natural habitat/host preference |
Skin, hair + nail Geophilic - soil (esp T ajelloi) |
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Dermophytes genera: Microsporum- site of infection + natural habitat/host preference |
Hair + Skin Zoophilic - cats + dogs (esp M canis) |
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Dermophytes genera: Epidermophyton- site of infection + natural habitat/host preference |
Skin + Nail Anthropophilic - human (esp E floccosum) |
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Classification of fungi based on Cell Morphology |
Yeast Yeast like fungi Molds/ filamentous Dimorphic fungi |
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Yeast - def’n + egs |
Unicellular + reproduce by budding Smooth creamy colonies on culture Capsulated true yeast w India Ink staining Eg. Cryptococcocus neoformans |
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Yeast like fungi |
Partly as yeast + partly as elongated cells w pseudohyphae Eg Candida albicans |
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Molds/filamentous fungi |
Forms true mycelia + vegetative/aerial hyphae + reproduce by spores Eg dermatophytes , rhizopus, mucor, aspergillus spp, penicillium spp |
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Dimorphic fungi |
Either yeast form (host tissues + culture) or filamentous form (soil + culture at 22oC) Eg Histoplasma capsulatum, Blastomyces dermatidis, Sporothrix schenckii, Coccidioides immitis |
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Dermatophytosis:- transmission + classical “Ringworm” lesion |
Direct - close human contact + trauma Indirect - sharing combs, bed sheets etc Zoophilic, Moisture, Crowded living conditions + Immunodeficiency Snake like annular lesions resembling worm burrowing at the margin |
