dermatophytes
DESCRIPTION
TRANSCRIPT
Dermatophytes(Superficial Mycoses)
(Skin Plants)
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Tinea
Ringworm (moth)
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Tinea corporis(the body)
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Tinea pedis(feet)
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Tinea unguium(nails)
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Tinea capitis(scalp)
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Tinea cruris(jock itch)
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Tinea barbae(bearded area)
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Tinea versicolor
(Spaghetti and meatballs) www.freelivedoctor.com
Ecology of Dermatophytes
To determine the source of infection
• Anthropophilic• Zoophilic• Geophilic
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Anthropophilic
Associated with humans only. Person -to-person transmission through contaminated objects (comb, hat, etc.)
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Zoophilic
Associated with animals. Direct transmission to humans by close contact with animals.
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Geophilic
Usually found in soil. Transmitted to humans by direct exposure.
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Geographic Distribution
Worldwide
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Dermatophytes3 Genera
• Trichophyton
• Microsporum
• Epidermophyton
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Trichophyton (19 species)
• Hair
• Skin
• Nails
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Trichophyton species
Large, smooth, thin wall, septate, pencil-shaped
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Trichophyton rubrum
Causes a chronic infection in patients with a cell-mediated immune defect.
(most common in SC blacks)
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Microsporum(13 species)
• Skin
• Hair
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Microsporum species
Thick wall, spindle shape, multicellular
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Microsporum canis
.
Most common etiologic agent of tinea in SC whites
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Epidermophyton floccosum
• Skin
• Nails
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Epidermophyton floccosum
Bifurcated hyphae with multiple, smooth, club shaped macroconidia (2-4 cells)
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Therapy
• Griseofulvin
• Tinactin
• Clotrimazole
• Miconazole
• Ketoconazole
• Itraconazole
• Terbinafinewww.freelivedoctor.com
Dermatophytid Reaction(ID)
• Dermatophyte infection on feet (not clinically evident)
• Ringworm Lesion on hand
(usually the dominant side)
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Dermatophytid Reaction(ID)
• Culture skin scrapings from feet
• Treat the tinea pedis
• The hand lesion (ID phenomenon) will respond to therapy of the foot.
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Dermatophyte Culture
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Dermatophytes
• It is not necessary to be an athlete to get athlete’s foot.
• A tinea (moth) does not cause skin lesions
• There are no worms in ringworm
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