superficial cutaneous
TRANSCRIPT
SUPERFICIAL & CUTANEOUS
MYCOSES
MYCOSES→ fungal infections acquired by man through inhalation
or inoculation by trauma into the skin
MYCOSES AND MYCOTIC INFECTIONS
→ only about 100 species of yeasts and molds cause disease in humans and animals
→ Dermatophytes and Candida species are commonly transmitted between humans
RISK FACTORS
→ Immunocompromised due to long-term antibiotic treatment
Use of immunosuppressive drugs: Cancer chemotherapy drugs, Corticosteroids
Drugs that prevent organ rejection
Disorders: AIDS, Burns, if extensive ; Diabetes ; Hodgkin lymphoma or other lymphomas; Kidney failure ; Lung
disorders, such as emphysema ; Leukemia
CLASSIFICATION OF MYCOSES
Superficial Mycoses Cutaneous MycosesSubcutaneous MycosesSystemic MycosesOpportunistic Mycoses
SUPERFICIAL MYCOSES
Noninvasive skin, hair, or nails
No cellular response from host
No pathological changes
Host unaware
Disease Causative Organisms
Incidence
Pityriasis versicolor
Seborrhoeic dermatitis including Dandruff
Follicular pityriasis
Malassezia furfur
(a lipophilic yeast)
Common
Tinea nigra Exophiala werneckii
Rare
White Piedra Trichosporon beigelii
Common
Black Piedra Piedraia hortae
Rare
Pityriasis versicolor
→ a chronic mild superficial infection of the stratum corneum
→ Causative Agent: Malassezia furfur complex ( M globosa, M restricta)
lipophilic yeast,
isolated from normal skin
and scalp
→ young adults
→Distribution: Worldwide, more common in TROPICAL climates
Pityriasis versicolorLesions:
discrete, serpentine
hyper or hypopigmented maculae on skin
Chest, upper back, arms, abdomen
Scaly, chalky , inflammation, and irritation are minimal
enlarge or coalesce
Pityriasis versicolorDiagnosis:
→ Direct microscopic examination (10-20% KOH,stained with calcofluor white)
Wood’s lamp
Pityriasis versicolorDiagnosis:
Culture is unnecessarySDA overlaid with peanut oil, olive oilDixon’s agar (glycerol-mono-oleate)
Pityriasis versicolorTreatment:
Selenium sulfide (1%) applied daily
Oral or topical azolesMild fungicides
Miconazoles
Opportunistic fungemia
→ catheter acquired infection common in neonates & adults undergoing lipid replacement therapy
→small embolic lesions in the lungs and other organs
Diagnosis: Blood drawn back from catheter, culture tip of catheter
Treatment: replace fluid and intravenous catheter
Pityriasis folliculitis
→ follicular papules and pustules
→ Back, chest, upper arms, neck, more seldom the face
→ Itchy
→ after sun exposure
Pityriasis folliculitisDiagnosis and Treatment
→ Scrapings or biopsy : yeasts at the mouths of infected follicles
→ Topical imidazole If lesions are extensive, ketoconazole, itraconazole
Prophylactic treatment 1x or 2x week to prevent relapse
Seborrheic Dermatitis
→ Host factors
→ Parkinson’s disease, AIDS
→ erythema and greasy scaling
→Scalp, face, eyebrows, ears, upper trunk
topical imidazole, ketoconazole, relapse is common
Malassezia Dermatitis
Causative Agent: Malassezia pachydermatis Phytosporum canis
Common yeast in
canine skin and external
ear canal
Microclimate alterations
host defenses are down
little zoonotic potential
Ketoconazole, miconazole
Malassezia DermatitisLesions:
Pruritus
Greasiness
Lichenification
Strong body odor
Staphylococcal pyoderma
Otitis externa
M pachydermatis from a dog ear
Peanut-shaped yeast
TINEA is Latin for “growing
worm”.
Tinea Nigra(Tinea Nigra Palmaris)
Causative Agent: Hortaea (Exophiala) werneckii
Chronic, asymptomaticsaprophyte in soil, compost, humus and
woodyoung women, warm coastal regions, tropical
Distribution: Central and South America, Australia, Southeast Asia, Africa
Tinea NigraLesions:
dark (brown to black) on palm, well demarcated macular lesions
No inflammatory reaction
Tinea NigraDiagnosis:
Direct microscopic examination (KOH)
brown to olivaceous
septate hyphae
2-celled yeastMelanized cell wall
Culture on SDA
mucoid
yeast-like
shiny black
Tinea NigraTreatment :
Whitfield’s ointment (benzoic acid compound)
2% salicylic acid, 3% sulfur
azole antifungal drugs
tincture of iodine
Miconazole nitrate, imidazoles, triazoles
PIEDRA
→ from the Spanish word stone→ fungus infection of the hair shaft
→ firm, irregular nodules→ multiple infections of the same strand
BLACK PIEDRA
Causative Agent : Piedraia hortae
Ascomycetous fungi
humans and primates
Distribution: Africa, Asia, Central, South America
can be confused with trichorrhexis nodosa and trichonodosis
soil is source of infection
BLACK PIEDRALesions:
Scalp hair
beard and moustache
axilla and groin hairs
discrete, hard, gritty , brown to black nodules
BLACK PIEDRADiagnosis & Treatment:
Direct microscopic examination (KOH)
Round to oval asci, curved to fusiform ascospores
Dark septate hyphae
Culture on SDA-CC
Very slow, dark brown to blackHeaped center with flat periphery
Short aerial mycelium
BLACK PIEDRADiagnosis & Treatment:
Usually shaving or cutting hair short
Terbinafine
WHITE PIEDRA
Causative Agent : Trichosporon beigelli, T cutaneum
Distribution : South America,AsiaN. America & Europe (sporadic)
soil, stagnant water, decaying fruit, spoiled food, sputum and body surfaces, horses
Face, axilla, genitals : commonScalp, eyebrows, eyelashes : less common
WHITE PIEDRALesions:
yellowish to white, soft, beige or greenish, irregular transparent sheath
WHITE PIEDRADiagnosis
Direct microscopic examination (10% KOH or 25% NAOH plus 5% glycerin)
Hyaline septate hyphae
Oval/rectangular arthroconidia
Blastoconidia
Culture on SDA with chloramphenicol, without cycloheximide
rapid
Cream-colored
Soft, membranous
Wrinkled radial furrows
Irregular folding
WHITE PIEDRATreatment:
Usually shaving or cutting hair short
1:200 bichloride mercury, benzoic acid & salicylic acid, 3% sulfur ointment, 2% Formalin, combinations
CUTANEOUS MYCOSES
keratinized tissue
restricted to non viable skin
unable to grow at 37° C
unable to grow in presence of serum
Host specific : keratinases, elastases, enzymes
DERMATOPHYTES
Dermatophytoses: infection of skin, hair and nails
nonviable skin: only hyphae and arthroconidia
sexual state belong to a single genus Arthroderma
GeneraPresence of
macroconidia;its
characteristicsTexture
Presence of microconidia,
its characteristics
Special name
Site of infection
Microsporum; large, spindle
shaped,multicellular form on ends of
hyphae
rough walled
“sheath of spores”
skin, hair, rare in nails
Trichophyton pencil shaped
macroconidia with blunt ends
are rare
smooth walled
“ghost hair”
Epidermophyton
only one- to five-celled,club
shaped macro are formed in
greenish-yellow colony which
mutates readily to form a sterile white growth
smooth walled x “ghost of
skin”skin and
nails, never hair
ECOLOGICAL GROUPS
GEOPHILIC : soil ; decompose keratinaceous debris
ZOOPHILIC: parasitic on animals
ANTHROPHILIC: man is exclusive host
CLINICAL MANIFESTATIONS
Tinea or ringworm – raised circular lesions
Tinea pedis : footTinea capitis: headTinea corporis: bodyTinea unguium: nails
Tinea cruris: crotch
Tinea pedis (Athlete’s foot)
Etiologic Agents: Trichophyton mentagrophytes, Trichophyton rubrum, Epidermophyton floccosum, Trichophyton interdigitale
chronic infection of the toe webs
matting or carpets with desquamated infectious scales
Tinea pedis by T rubrum (left) ; severe maceration (right)
Moccasin type by E floccosum (left) ; vesicular type by T interdigitale (right)
Tinea unguium (Onychomycosis)
Etiologic Agents: T rubrum, T interdigitale
invasion of the nail plate
one or more nails of the hands or feet
Onychomycosis : nondermatophytic fungal nail infection (yeasts)
T rubrum
Tinea corporis
Etiologic Agents: E floccosum, T rubrum, T tonsurans, M canis and M gypseum (geophilic infections)
glabrous or non hairy areas of the skin
grow within dead keratinized tissue
M canis ; after exposure to infectious kittens
Tinea cruris
Etiologic Agents: E floccosum, T rubrum, T interdigitale
proximal medial thighs, perineum and buttocks
Jock Itch - more common in males
military personnel, sharing of towels and clothing
Erythematous lesions on the thighs
Granular strain Downy strain
Tinea capitis
scalp and hair
begin at scalp with hyphal invasion
2 types: Ectothrix and Endothrix
Ectothrix Infection
around hair shaft
chain of spores imparting greenish to silvery fluorescence
Etiologic agents: M. canis, M. gypseum, T. equinum and T. verrucosum
Endothrix Infection
within hair shaft
Etiologic agents: T tonsurans, T. violaceum
black dot, weakened and break
All are anthrophilic
Kerion
Kerion: severe combined inflammatory and hypersensitivity reaction
Favus
Favus: acute inflammatory infection of hair follicle leading to scrutula or crusts
T. schoenleinii
Tinea barbae
Etiologic agents: T mentagrophytes
bearded region
zoophilic dermatophyte : pyogenic infection
Tinea manuum
Interdigital areas and palmar surfaces
Occurs almost exclusively in adults
Itchiness is moderate and minimal
Slow progress : months to years
1st pattern : ringworm pattern at dorsum of hand
2nd pattern : chronic scaling at palmar surfaceDry, hyperkeratotic, thickened, fine, silvery white scales
Tinea imbricata“Tokelau”
Etiologic agents: Trichophyton concentricum
Distribution: Southwest Polynesia, Melanesia, Southeast Asia, India, and Central America
Concentric rings; Chronic non-itchy rash
Tricophytid Reaction
hypersensitivity to metabolic products of fungus producing dermatophyids
LABORATORY DIAGNOSIS
Skin scrapings → KOH mount
Nail scrapings and clippings
Ectothrix Flouresce under Wood’s Lamp
(Bright greenish yellow)
Cuticle destroyed
Endothrix Do not flouresce
Cuticle intact
HAIR
Ectothrix Microsporum canisM. gypseumT. equinumT.verrucosum
Endothrix ALL ANTRHOPHILIC!Trichophyton tonsuransTrichophyton villaceum
Culture
Non-selective: Saboraud’s Dextrose Agar (SDA)
Selective: SDA-CC (Mycosel or Mycobiotic agar)Dermatophyte test medium
Incubation: room temperature, at least 2 weeks
Culture
SDA – CC for 1-3 weeks
Identification
Gross color & texture
Microscopic characteristics
Confirm/compare with: Written descriptions
DrawingsPhotographs
TREATMENT
Removal of infected and dead epithelial structures
Apply topical antifungal chemical or antibiotic
keep dry, avoid shared bathing facilities and infected pets
Infection Oral Topical Duration
Tinea capitis griseofulvin terbinafine
Shampoos and miconazole cream , ketoconazole, itraconazole
Weeks
Tinea corporis, Tinea pedis
itraconazole terbinafine
MiconazoleNitrateTolnaftateclotrimazole
2-4 weeks
Tinea unguium itroconazole terbinafine
---- (surgical removal)
Relapses are common
Microsporum gypseum
Geophilic
single inflammatory skin/scalp lesion
Distribution: worldwide
Flat, spreading suede-like to granular
Cinnamon growth
REVERSE
Yellow brown pigment on reverse of colony
Symmetrical, ellipsoidal
Thin-walled verrucose macroconidia
Distal end round, proximal end blunt
Trichophyton mentagrophytes
Zoophilic :mice, cats,horses,sheep,rabbits
Inflammatory skin/scalp lesions
Ectothrix infection
Distribution: worldwide
REVERSE
Flat, white to cream color, powdery to granular surface
Reverse pigment is yellowish brown to pinkish
Red brown submerged peripheral fringe
Spherical microconidia
Dense clusters, “en grappe”
Spiral hyphae
Smooth, thin-walled, clavate, multiseptate macroconidia
Trichophyton rubrum
Anthropophilic
Chronic infection of skin & nails, rarely scalp
Ectothrix and Endothrix hair infection
Distribution: worldwide
REVERSE
White, suede-like to downy
Deep wine red pigment on reverse side
Moderate to scanty slender clavate to pyriform microconidia
Macroconidia are absent,Closterospore-like projections in some strains
Trichophyton tonsurans
Variation in texture and color
Suede-like to powdery
Flat with raised center or folded
With radial grooves
Pale buff to yellow
Varying sizes and shapes of microconidia
Long clavate to pyriform
Very occasional clavate macroconidia
Partial requirement for thiamine
Trichophyton concentricum
Anthrophophilic
Tinea imbricata
Distribution:Pacific Islands of Oceania
Southeast AsiaCentral and South America
Raised and folded, glabrous and suede-like
White to cream color
Deeply folded into the agar
No microconidia and macroconidia
Trichophyton schoenleinii
Waxy and glabrous
Deeply folded honeycomb-like thallus with subsurface growth
Antler “nail head” hyphae
Favic chandeliers
No microconidia and macroconidia
Epidermophyton floccosum
Anthrophophilic
No hair invasion in vivo
Distribution: worldwide
Greenish brown or “khaki” colored
Suede-like surface, raised and folded center, flat periphery
Yellowish brown reverse pigment
White pleomorphic tufts of mycelium
Smooth thin-walled macroconidia in clusters growing directly from hyphae
No microconidia
Numerous chlamydoconidia in older cultures
Microsporum canis
Zoophilic:Cats & Dogs
Invades skin & hair, rarely nails
Distribution: worldwide
White cottony growth
Golden yellow reverse pigment
Spindle shaped, thick walled, verrucose macroconidiawith a terminal knob
Trichophyton verrucosum
Zoophilic:Cattle
Infect humans : direct contact, infected fomites
Highly inflammatory: scalp, beard,exposed areas
Ectothrix infection: flouresce only in cattles
Distribution: worldwide
Glabrous, heaped, folded white colony
No reverse pigments
Thiamine-enriched media: clavate – pyriform microconidia
Characteristic rat tail or string bean shape
END.