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
DERMATOPHYTES Digest keratin by their keratinases Resistant to cycloheximide Classified into three groups depending on their usual habitat
All three dermatophytes contain virulence factors that allow them to invade the skin, hair, and nails Keratinases Elastase Proteinases
DERMATOPHYTES ANTROPOPHILIC Trichophyton rubrum... GEOPHILIC Microsporum gypseum... ZOOPHILIC Microsporum canis: : cats and dogs Microsporum nanum: : swine Trichophyton verrucosum: horse and swine
Zoophilic dermatophytes
Microscopic characteristics of dermatophyte genera Microsporum Epidermophyton Trichophyton
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 )
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)
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)
DERMATOPHYTOSIS Transmission i Close human contact Sharing clothes, combs, brushes, towels, bedsheets... (Indirect) Animal-to-human contact (Zoophilic)
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
DERMATOPHYTOSIS Diagnosis i B. Culture Mycobiotic agar Sabouraud dextrose agar
DERMATOPHYTES Identification A. Colony characteristics B. Microscopic morphology Macroconidium Microconidium Microsporum----fusiform fusiform---------------(+) Epidermophyton clavate-----------------(-) Trichophyton-- -(few)cylindrical/ --- --(+) clavate/fusiform single, in clusters
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
DERMATOPHYTOSIS Treatment Topical Oral l Miconazole, clotrimazole, econazole, terbinafine... Griseofulvin Ketaconazole Itraconazole Terbinafine
Routine Laboratory Turn Around Times Management of Cutaneous fungal infections. David Ellis, Mycology Unit, Women s and Children s Hospital, Adelaide. www.mycology.adelaide.edu.au Organism Direct Micro Culture Identification Total C. albicans 24 hrs 48 hrs 3 hrs 2-3 days Other Yeasts 24 hrs 48 hrs 72-96 hrs 5-8 days Dermatophytes 24 hrs 14-28 days 1-28 days 14-42 days Other Molds 24 hrs 5-28 days 1-28 days 5-42 days
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)
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.
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.
Direct Microscopy- (KOH 10% preparation) : Branching hyphae is present (compatible with Dermatophyte). Direct Microscopy- (KOH 10% preparation) : Typical dermatophyte hyphae is present.