Superficial Mycoses PDF

Superficial Mycoses......... Superficial Mycoses and Dermatophytoses □ Predisposing factors: Humidity Immunosuppression Poor hygiene □ Affects only the cornified layer of the skin or the epidermal area with strong affinity to keratin  Superficial Mycoses Causative agents: E...

Superficial Mycoses......... Superficial Mycoses and Dermatophytoses □ Predisposing factors: Humidity Immunosuppression Poor hygiene □ Affects only the cornified layer of the skin or the epidermal area with strong affinity to keratin  Superficial Mycoses Causative agents: Exophiala/Hortaea werneckii Malassezia furfur Piedraia hortae Trichosporon ovoides(T. beigelii) Trichophyton tonsurans/T.violaceum https://doi.org/10.1128%2FCMR.00003-11 Exophiala werneckii Disease: Tinea nigra Chronic superficial fungal infection of the palms brown to black macules (palmar and plantar and other surfaces of the skin) Well-defined dark patch with irregular margin, 1-5 cm in diameter on palm; “stained appearance” Direct Microscopy: 10% KOH Exophiala werneckii Initially colonies are mucoid, yeast-like and shiny black. (young yeast) Abundant aerial mycelia and become velvety, dark olivaceous in colour. (mature mould) pigmented brown to dark (dematiaceous) septate hyphal elements 2-celled yeast cel while it can form annellides upon aging Management & Treatment: ❑ Sulfur soap, salicylic acid, azoles ❑ Topical treatment Whitfield's ointment (benzoic acid compound) Imidazole agent twice a day for 3-4 weeks 9 Malassezia furfur ❑ lipophilic basidiomycetous yeasts ❑ Found as a normal flora on the skin Diseases : Pityriasis versicolor/tinea versicolor Pityriasis folliculitis Seborrhoeic dermatitis; Dandruff Systemic infection Major Clinical Manifestation:Tinea/ Pityriasis Versicolor Hyper- or hypopigmented of the skin. Lesions are well-demarcated (white, pink or brownish) “Fawn-colored macules” are the most common presentation Trunk and upper arms Rarely on neck and face Tinea/ Pityriasis Versicolor Pityrosporum folliculitis ❑ follicular papules and pustules Fungal acne Seborrhoeic dermatitis ❑ erythema and scaling in areas with a rich supply of sebaceous glands ❑ changes in quantity and composition of sebum due to Malassezia spp ❑ Degradation of sebum and and consumption of fatty acids 15 Systemic Infection (M. furfur) ❑ common among infants as venous IV catheter acquired Intravenous infusions of lipid/lipid replacement therapy Pneumonia results from emboli from the infected IV catheter Laboratory Diagnosis 10% KOH (glycerol w/ Parker ink or Calcofluor white) of skin scraping Short septate hyphae in short chain Yeast cells look like phialioconidium Spaghetti and Meatballs “Spaghetti and meatballs” on Wood’s Lamp  KOH w/ Iodine Gomori Methenamine Silver nitrate  Laboratory Diagnosis 2. Culture For systemic infection Sources of fatty acids: natural oil and olive oil Sabouraud's dextrose agar or Sheep blood agar containing cycloheximide (Acti-dione) with olive oil Dixon's agar containing glycerol mono-oleate 20  Malassezia furfur Colonies of Malassezia furfur on Dixon's agar (oleic acid as source of fatty acid) Helpful Features □ White discoloration of skin or light brown discoloration □ “Spaghetti and meatballs” □ Oil and fatty acid requirements Piedraia hortae Ascomycetous fungus Common in Central and South America and South-East Asia Disease: Black piedra ▪ Chronic fungal infection of the hair shaft ▪ mostly affects young adults ▪ epidemics in families Piedraia hortae (Black piedra) Clinical Manifestations: ❑ Does not penetrate the hair follicle ❑ Scalp hair: rough, sandy ❑ Infected hairs: hard black nodules on the shaft ❑ Nodules: hard, fusiform, firmly attached to hair shaft Laboratory Diagnosis Clinical Material: hairs with hard black nodules 1. Direct Microscopy: 10% KOH w/ Parker ink; calcofluor white ▪ darkly pigmented nodules: hair shaft ▪ Nodules: pigmented center containing ascospores (Larone)  Laboratory Diagnosis 2. Culture: Colonies are greenish black Take about 21 days (Larone) Management and Treament: ❑ shave or cut the hairs short Trichosporon ovoides ❑ *T. beigelii has been obsolete ❑ Disease: White piedra superficial cosmetic fungal infection of the hair shaft Affects scalp, axilla, facial and genital hair  White piedra ❑ Clinical Manifestations: common in young adults Nodules: white, follicles not affected irregular, soft, white or light brown nodules firmly adhering to the hairs 1.0 - 1.5 mm in length no pathological changes are elicited White piedra  Laboratory Diagnosis 1. Direct Microscopy: 10% KOH and Parker ink; calcofluor white Arthtoconidia and Blastoconidia (pseudohyphae)  Laboratory Diagnosis 2. Culture: ❑ primary isolation media (Yeast base agar) white or yellowish to deep cream colored smooth, wrinkled, velvety, dull colonies with a mycelial fringe. Trichosporon beigelii Management and Treatment: Shave the hair Topical: imidazole agent B. Dermatophytes (Cutaneous mycoses) - fungal infections involving the dermis and its appendages (hair follicles and nails) o Dermatophytoses - "ringworm" disease (mycotic infection) of the nails, hair, and/or stratum corneum of the skin caused by fungi called dermatophytes. o Dermatomycoses - more general name for any skin disease caused by a fungus. - invasion of the cutaneous tissues by other fungi.  IMPORTANT CAUSATIVE AGENTS □ Microsporum □ Trichophyton □ Epidermophyton □ Dermatophytes are keratinophilic □ Keratin is a major protein found in horns, hooves, nails, hair, and skin. □ use keratin as a source of nitrogen  Dermatophytoses of the skin □ Clinical Manifestations: “ringworm” □ Differential Diagnosis: Psoriasis: dry and circinate borders Ezcema:no clear center TINEA  ASSIGNMENT RINGWORM PART OF BODY MAIN CAUSATIVE INFECTION INFECTED AGENT Tinea capitis SCALP Trichophyton, Microsporum audouinii Tinea barbae HAIRY PART OF Trichophyton rubrum FACE Trichophyton verrucosum Tinea corporis FACE, ARMS, Microsporum canis, TRUNKS Trichophyton rubrum & mentagrophytes Tinea manuum HANDS Trichophyton rubrum  ASSIGNMENT RINGWORM PART OF MAIN CAUSATIVE AGENT INFECTION BODY INFECTED Tinea cruris GROIN Trichophyton rubrum, T. interdigitale Epidermophyton floccosum Tinea pedis FEET Trichophyton rubrum, Epidermophyton floccosum Tinea fasciae FACE Tinea imbricata EXTREMITIES Trichophyton concentricum Tinea unguium FINGERNAILS Epidermophyton floccosum Common Dermatomycoses □ Diseases: □ Tinea capitis- scalp & eyebrows □ Tinea barbae-hairy parts of face □ Tinea corporis-face, arms, trunks □ Tinea cruris-genitalia □ Tinea manuum-between fingers □ Tinea pedis-feet □ Tinea fascie- face □ Tinea imbricata- special form of Tinea corporis usually concentric rings on skin □ Tinea ungium- fingernails Tinea or “ringworm”: basic lesion Tinea capitis (scalp) Tinea barbae (hairy part of face)  Differential Diagnoses: Alopecia areata Alopecia: no scaling  Differential Diagnoses: Psoriasis Psoriasis: no loss of hair; silvery scaling  Differential Diagnoses: Seborrheic dermatitis Seborrheic dermatitis: diffuse hair loss Tinea corporis (face, arms, trunks) Tinea fascia (face) Tinea manuum (hand) Tinea pedis (feet) Tinea imbricata (Concentric rings on skin) Tinea unguium (fingernails) Tinea cruris (groin) – jock itch LABORATORY TESTS FOR DERMATOPHYTES □ Direct Microscopy using 10% KOH or 20% KOH □ with using slight heat or addition of DMSO ❏ Culture method ❏ SDA ❏ DTM ❏ Potato dextrose agar- demonstrate pigment production by Trichophyton rubrum ❏ CMA + 10% glucose- T. rubrum is differentiated from T. mentagrophytes by amount of pigment produced ❏ Rice media HAIR BAITING TEST T. mentagrophytes: (+), T. rubrum: (-) M. canis (+), M. equinum (-)  Microsporum Epidermophyton Trichophyton Site affected Hair and Skin Skin and Nails Hair, skin and nails Macroconidia Fusiform/ Spindle Shaped Club shaped, Beaver tail Clavate/ Cylindrical shaped Rare Microconidia None Abundant (A) MACROCONIDIA (B) MICROCONIDIA Microsporum species Microsporum audouinii Microsporum gypseum Microsporum canis Microsporum audouinii Microconidia absent or bizarre if present Fluorescence with Woods’ lamp, Atypical vegetative hyphae with terminal obverse: gray to tan white chlamydospore reverse:light salmon with red brownish center Apple green fluorescence of ectothrix hair Pectinate (comblike) hyphae are commonly seen Microsporum gypseum Obverse: Cinnamon color, powdery colonies reverse: light tan 3-9 celled, broadly spindle shaped, rough walled macroconidia Terminal ends rounded Microconidia, if present, single or in small clusters  Microsporum canis Teleomorph: Arthroderma otae Large, multicelled, spindle, beak-like shaped rough Membranous colonies- thin colonies with feathery macroconidia edge; center of colony is white to buff, edges are Microconidia few or absent orange yellow Terminal ends sometimes curved reverse: lemon yellow/yellow orange Green yellow fluorescence of ectothrix hair Epidermophyton species Epidermophyton floccosum Epidermophyton floccosum □ Tinea unguium and tinea cruris are often caused by this fungus. / Epidermophyton floccosum □ Colony: Center of colonies tend to be folded, khaki green to yellow color reverse: yellow brown with folds □ Microscopic: Large, multicelled, club-shaped, smooth-walled macroconidia, single in clusters Microconidia NOT formed moderately thick , smooth walls (beaver tails) Epidermophyton floccosum □ Areas affected: skin and nails □ Disease: Tinea cruris or “jock itch” Often start on the scrotum and spread to the groin as dry, itchy lesions Source of infection: □ Sharing of linens, towels or clothes □ Athletes, soldiers, ship crews Tinea cruris (groin) – jock itch Trichophyton species □ □ Most common species include: Trichophyton mentagrophytes T. rubrum T. tonsurans T. verrucosum T. violaceum T. schoenleinii T. ajelloi (rare infects humans).  Trichophyton species Trichophyton White, pink, granular, fluffy colonies; with mentagrophytes occasionally light yellow periphery reverse: red brown Trichophyton White downy-pink granules, rugal folds are rubrum common reverse: yellow when young, wine red with age Trichophyton White, tan-yellow or rust, suede like to powdery. tonsurans Wrinkled and heaped or sunken crater reverse: yellow tan to rust red Trichophyton Irregularly hip, smooth, white cream with radiating schonleinii grooves reverse: white Trichophyton Port-wine-deep violet, heaped on flat with waxy violaceum surface Pigment maybe lost on subculture Trichophyton Macronidia: few, smooth walled, mentagrophy cigar shaped, connected to hyphae tes with definite narrow attachment Micronidia: spherical often in grape-like clusters spiral hyphae Trichophyton Macroconidia: few, rubrum smooth-walled, pencil-shaped Microconidia tear shaped and lateral along hyphae T. tonsurans Macroconidia absent, rare, distorted Many microconidia of various shape and sizes “Balloon Forms”- aged pleomorphic microconidia T. schonleinii Conidia absent Favic chandeliers (Antler Hyphae) and chlamydospores common T. violaceum Conidia absent Swollen hyphae containing cytoplasmic granules T. verrucosum Macroconidia: “rat tail”, 3-5 cells thin walled Microconidia: large, clavate, lateral