All three dermatophytes contain virulence factors that allow them to invade the skin, hair, and nails. Keratinases. Elastase.

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1 DERMATOPHYTOSIS (=Tinea = Ringworm) Infection of the skin, hair or nails caused by a group of keratinophilic fungi, called dermatophytes Microsporum Epidermophyton Hair, skin Skin, nail Tih Trichophyton ht Hair, skin, nail

2 DERMATOPHYTES Digest keratin by their keratinases Resistant to cycloheximide Classified into three groups depending on their usual habitat

3 All three dermatophytes contain virulence factors that allow them to invade the skin, hair, and nails Keratinases Elastase Proteinases

4 DERMATOPHYTES ANTROPOPHILIC Trichophyton rubrum... GEOPHILIC Microsporum gypseum... ZOOPHILIC Microsporum canis: : cats and dogs Microsporum nanum: : swine Trichophyton verrucosum: horse and swine

5 Zoophilic dermatophytes

6 Microscopic characteristics of dermatophyte genera Microsporum Epidermophyton Trichophyton

7 DERMATOPHYTOSIS Pathogenesis and Immunity Contact and trauma Moisture Crowded living conditions Cellular immunodeficiency (chronic inf.) Re-infection is possible (but, larger inoculum is needed, the course is shorter )

8 DERMATOPHYTOSIS Clinical l Classification Infection is named according to the anatomic location involved: a. Tinea barbae e. Tinea pedis (Athlete s foot) b. Tinea corporis f. Tinea manuum c. Tinea capitis g. Tinea unguium uium d. Tinea cruris (Jock itch)

9 DERMATOPHYTOSIS Clinical i l manifestations i Skin: Circular, dry, erythematous, scaly, itchy lesions Hair: Typical lesions, kerion, scarring, alopecia Nail: Thickened, deformed, friable, discolored nails, subungual debris accumulation Favus (Tinea favosa)

10 DERMATOPHYTOSIS Transmission i Close human contact Sharing clothes, combs, brushes, towels, bedsheets... (Indirect) Animal-to-human contact (Zoophilic)

11 DERMATOPHYTOSIS Diagnosis i I. Clinical l Appearance Wood lamp (UV, 365 nm) II. Lab A. Direct microscopic examination (10-25% KOH) Ectothrix/endothrix/favic hair

12 DERMATOPHYTOSIS Diagnosis i B. Culture Mycobiotic agar Sabouraud dextrose agar

13 DERMATOPHYTES Identification A. Colony characteristics B. Microscopic morphology Macroconidium Microconidium Microsporum----fusiform fusiform (+) Epidermophyton clavate (-) Trichophyton-- -(few)cylindrical/ (+) clavate/fusiform single, in clusters

14 DERMATOPHYTES Identification i C. Physiological i l tests t In vitro hair perforation test Special amino acid and vitamin requirements Urea hydrolysis Growth on CMA 1% glucose medium Growth on polished rice grains Temperature tolerance

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16 DERMATOPHYTOSIS Treatment Topical Oral l Miconazole, clotrimazole, econazole, terbinafine... Griseofulvin Ketaconazole Itraconazole Terbinafine

17 Routine Laboratory Turn Around Times Management of Cutaneous fungal infections. David Ellis, Mycology Unit, Women s and Children s Hospital, Adelaide. Organism Direct Micro Culture Identification Total C. albicans 24 hrs 48 hrs 3 hrs 2-3 days Other Yeasts 24 hrs 48 hrs hrs 5-8 days Dermatophytes 24 hrs days 1-28 days days Other Molds 24 hrs 5-28 days 1-28 days 5-42 days

18 REPORT OF LABORATORY INVESTIGATION Medical Mycology Patient s name: Labno: no.: Date: Sender: Source: Scalp scales/ scalp hair/ skin scales/ toenail/ fingernail/ toewebs/ groin/ Ι- Direct Examination: KOH 10% preparation Blue de methylene staining Scotch tape method *Positive Result: Fungus elements present in skin, Nail and scalp: Typical dermatophyte hyphae breaking up into arthroconidia (Dermatophytosis) Branching filaments (Dermatophytosis) Septate, branched hyphae and budding cells (Malassezia furfur or other Malassezia spp.) Budding cells in different size & shapes (Malassezia furfur or other Malassezia spp.) Pseudohyphae and budding cells (Candidiasis) Long filaments, small coccoid forms and rod-like organism (Corynebacterium minutissmum) Only Budding cells (Candida spp., Saccharomyces spp., or other true yeasts) Fungus elements present in scalp hair: spores outside the hair shaft (Ectothrix) spores inside the hair shaft (Endothrix) mycelium and arthrospores inside the hair shaft (Favus) *Negative Result: Fungal elements not present. II- Culture: Fungus not Isolated. Specimen/ Culture Unsatisfactory. Organism(s) Isolated/ Identified: Comment: Medical Mycologist (PhD)

19 گزارش نتيجه آزمايش قارچ شناسی طريقه Direct Microscopy- (KOH 10% preparation) p : Typical dermatophyte hyphae breaking up into arthroconidia (Dermatophytosis). Direct Microscopy- (KOH 10% preparation) : Typical dermatophyte hyphae is present.

20 گزارش نتيجه آزمايش قارچ شناسی طريقه Direct Microscopy- (KOH 10% preparation) : Branching hyphae is present (compatible with Dermatophytic mycelium). Direct Microscopy- (KOH 10% preparation) : Typical dermatophyte hyphae is present.

21 Direct Microscopy- (KOH 10% preparation) : Branching hyphae is present (compatible with Dermatophyte). Direct Microscopy- (KOH 10% preparation) : Typical dermatophyte hyphae is present.

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