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Dermatophytes (Superficial Mycoses). (Skin Plants). Tinea. Ringworm (moth). Tinea corporis (the body). Tinea pedis (feet). Tinea unguium (nails). Tinea capitis (scalp). Tinea cruris (jock itch). Tinea barbae (bearded area). Tinea versicolor (Spaghetti and meatballs) .
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Dermatophytes(Superficial Mycoses) (Skin Plants)
Tinea Ringworm (moth)
Tinea versicolor (Spaghetti and meatballs)
Ecology of Dermatophytes To determine the source of infection • Anthropophilic • Zoophilic • Geophilic
Anthropophilic Associated with humans only. Person -to-person transmission through contaminated objects (comb, hat, etc.)
Zoophilic Associated with animals. Direct transmission to humans by close contact with animals.
Geophilic Usually found in soil. Transmitted to humans by direct exposure.
Geographic Distribution Worldwide
Dermatophytes3 Genera • Trichophyton • Microsporum • Epidermophyton
Trichophyton (19 species) • Hair • Skin • Nails
Trichophyton species Large, smooth, thin wall, septate, pencil-shaped
Trichophyton rubrum Causes a chronic infection in patients with a cell-mediated immune defect. (most common in SC blacks)
Microsporum(13 species) • Skin • Hair
Microsporum species Thick wall, spindle shape, multicellular
Microsporum canis . Most common etiologic agent of tinea in SC whites
Epidermophyton floccosum • Skin • Nails
Epidermophyton floccosum Bifurcated hyphae with multiple, smooth, club shaped macroconidia (2-4 cells)
Therapy • Griseofulvin • Tinactin • Clotrimazole • Miconazole • Ketoconazole • Itraconazole • Terbinafine
Dermatophytid Reaction(ID) • Dermatophyte infection on feet (not clinically evident) • Ringworm Lesion on hand (usually the dominant side)
Dermatophytid Reaction(ID) • Culture skin scrapings from feet • Treat the tinea pedis • The hand lesion (ID phenomenon) will respond to therapy of the foot.
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