DERMATOPHYTOSIS (Ti(=Tinea = Ringworm)
IInfection of the skin, hair or nails caused by a group of keratinophilic fungi, called dermatophytes
¨ Microsporum Hair, skin T ¨ Epidermophyton Skin, nail ¨ TihTrichop hthyton HiHair, skin, na il DERMATOPHYTES
IDigest keratin by their keratinases IResistant to cycloheximide IClassified into three groups depending on their usual habitat All three dermatoppyhytes contain virulence factors that allow them to invade the skin, hair, and nails
Keratinases
Elastase
Proteinases DERMATOPHYTES
IANTROPOPHILIC Trichophyton rubrum... IGEOPHILIC Microsporum gypseum... IZOOPHILIC Microsporum canis: cats and dogs Microsporum nanum: swine Trichophyton verrucosum: horse and swine… Zoophilic dermatophytes Microscopic characteristics of dermatophyte genera
Microsporum Epidermophyton Trichophyton DERMATOPHYTOSIS PhPathogenesi s and Immuni ty
IContact and trauma IMoisture ICrowded living conditions ICellular immunodeficiency Æ(()chronic inf.) IReRe--infectioninfection is possible (but, larger inoculum is needed, the course is shorter ) DERMATOPHYTOSIS Clllinical Cllfassification
IInfection 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 d. Tinea cruris (Jock itch) DERMATOPHYTOSIS Clini ca l manifestat ions
ISkin: Circular, dry, erythematous, scaly, itchy lesions IHair: Typical lesions,”kerion”, scarring, “l“alopeci i”a” INail: Thickened,,fm, deformed, friable, discolored nails, subungual debris accumulation IFavus (Tinea favosa) DERMATOPHYTOSIS TiiTransmission
IClose human contact ISharing clothes, combs, brushes, towels, bedsheets... ( Indirect ) IAnimalAnimal--toto--humanhuman contact (Zoophilic) DERMATOPHYTOSIS Diagnosi s
I. Clllinical Appearance Wood lamp (UV, 365 nm) II. Lab A. Direct microscopic examination ((1010--2525%% KOH) Ectothrix/endothrix/favic hair DERMATOPHYTOSIS Diagnosi s
B. Culture Mycobiotic agar Sabdbouraud dextrose agar DERMATOPHYTES Iden tifica tion
A. Colony characteristics B. Microscopic morphology Macroconidium Microconidium Microsporum----fusiform------(+) Epidermophyton clavateclavate------((--)) Trichophyton-- -(few)cylindrical/ --- -- (+) clavate/fusiform single, in clusters DERMATOPHYTES Ident ificat ion C. Physi ol ogi cal test s I In vitro hair perforation test I Special amino acid and vitamin requirements I Urea hhdliydrolysis I Growth on CMA 11%% glucose medium I Growth on polished rice grains I Temperature tolerance
DERMATOPHYTOSIS Treatment
ITopical Miconazole, clotrimazole, econazole, terbinafine... IOral 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:Lab 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 ((py)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)
طريقه گزارش نتيجه آزمايش قارچ شناسی
I Direct Microscopy- Microscopy- (KOH 1010%% pppreparation ): Typical dermatophyte hyphae breaking up into arthroconidia ((DermatophytosisDermatophytosis).).
I Direct Microscopy-Microscopy- (KOH 1010%% preparation) : Typical dermatophyte hyphae is present. طريقه گزارش نتيجه آزمايش قارچ شناسی
Direct Mi croscopycroscopy-- (KOH 1010%% preparation) : Branching hyphaeis present (compatible with Dermatophytic mycelium).
Direct MicroscopyMicroscopy--(KOH 10%%ti) preparation) : Typical dermatophyte hyphae is present. Direct Mi croscopycroscopy-- (KOH 10%10% preparation) : Branching hyphae is present (compatible with DermatophyteDermatophyte).).
Direct MicroscopyMicroscopy-- (KOH 10%10% preparation) : Typical dermatophyte hyphae is present.