U3 LEC: CUTANEOUS MYCOSES Flashcards
This refers to fungal infections in the hair, skin, nails
Cutaneous Mycoses
Some fungi have this protein that destroys keratin
Keratinase
Disease
Dermatophytosis
Causative organisms
Dermatophytes
- Microsporum
- Trichophyton
- Epidermophyton
This refers to “earth loving” organisms, inhabit soil where they decompose keratinaceous debris
Geophilic
Geophilic organisns can come from?
- dead animals
- free-living soil saprophytes
These organisms are parasitic on animals
Zoophilic
These organisms are primarily parasitic to man, for maintenance and dissemination of species.
Anthropophilic fungi
Examples of Anthropophilic fungi
- Microsporum audouinii
- Trichophyton rubrum
- Trichophyton schoenleinii
- Trichophyton tonsurans
- Trichophyton violaceum
Microsporum
Macroconidia: rough walled
Microconidia: present
Trichophyton
Macroconidia: smooth walled
Microconidia: present
Epidermophyton
Macroconidia: smooth walled
Microconidia: none
Conidia present in Epidermophyton
Chlamydoconidia
Formation of arthroconidia on the outside of hair shaft, cuticle of hair is destroyed
Ectothrix
Positive for Wood’s lamp test
Ectothrix (will fluoresce)
Examples of Ectothrix
- Microsporum canis
- Microsporum gypseum
- Trichophyton equinum
- Trichophyton verrucosum
Formation of arthroconidia within hair shaft, cuticle of hair remains intact
Endothrix
Negative under Wood’s lamp
Endothrix (do not fluoresce)
T/F: All endothrix-producing agents are anthropophilic.
- Trichophyton tonsurans
- Trichophyton violaceum
This refers to the balding of the scalp, eyebrow and eyelashes.
Tinea capitis
Causative agent of Tinea capitis
- Microsporum
- Trichophyton
Two distinct forms of Tinea capitis
- Gray patch ringworm
- Black dot ringworm
Tinea capitis
common childhood disease
Gray patch ringworm
Tinea capitis
Ectothrix hair involvement
Gray patch
Gray patch ringworm
Lesions and color of hair shaft
Lesions:
Luster and color of hair shaft: may be lost
Causative agent of Gray patch ringworm
- Microsporum audouinii
- Microsporum ferrugineum
Tinea capitis
Endothrix hair involvement
Black dot ringworm
Black dot ringworm
Site of infection
Hair follicle
Black dot ringworm
Hair shafts and color
Hair shafts: brittle, infected, breaks off
Color: black dot stubs
Causative agent of Black dot ringworm
- Trichophyton tonsurans
- Trichophyton violaceum
Tinea capitis
Risk factors
Age: toddlers and school-age children
Exposure to other children: close physical contact in schools and child care centers
Exposure to pets: touching or petting the animal
Tinea capitis
Signs and symptoms
itchy, scaly, bald patches
Tinea capitis
Treatment
- 2% ketoconazole shampoo
- 1% or 2.% selenium sulfide shampoo
This is characterized by a scutulum or cup shaped crusts, made up of mass of mycelia & epithelial debris.
Tinea favosa
Causative agent of Tinea favosa
Trichophyton schoenleinii
Tinea favosa is the ______ scarring form of tinea capitis.
chronic
Infection of Tinea favosa happens in the?
hair follicle
This is the characterized by rings with scaly centers on non-hairy skin.
Tinea corporis
Tinea corporis
Causative agent
- Epidermophyton floccosum
- Trichophyton
- Microsporum
Tinea corporis
commonly seen in?
- arms, legs, buttocks, trunk
- glabrous skin
Tinea corporis
Causes
- human to human
- animal to human
- object to human
- soil to human
Tinea corporis
Risk factors
- warm cimate
- share clothing
- sports with skin contact
- wearing tight or restrictive clothing
- weak immune system
Tinea corporis
Treatment
- topical therapy (at least 2cm once or twice a day for atleast 2 weeks)
- topical azoles
This is characterized by concentric rings.
Tinea imbricata
Causative agent of Tinea imbricata
Trichophyton concentricum
Tinea imbricata
Mainly affects?
primitive and isolated environment in developing countries
This can be seen in bearded areas of face & neck
Tinea barbae
Tinea barbae
Exlcusive in?
older adolescent and adult males
Tinea barbae
Clinical presentation
inflammatory, deep, kerionlike plaques and non inflammatory superficial patches
Tinea barbae
resembles?
Tinea corporis or bacterial folliculitis
Tinea barbae
It may be viewed as an occupational disease among?
cattle farmers
Tinea barbae
Treatment
- shaving or hair depilation (warm compress to remove crusts and debris)
- topicals (griseofulvin)
This is also known as the jock itch.
Tinea cruris
Tinea cruris
Infections are mainly seen in?
moist groin area
Tinea cruris
Causative agents
- Epidermophyton floccosum
- Trichophyton rubrum
Tinea cruris
most common in?
men and adolescent boys
Tinea cruris
Appearance of rash
red, flaky, scaly and itches or burns
Tinea cruris
Treatment
- topical terbinafine
- itraconazole
This is also known as the Athlete’s foot
Tinea pedis
Tinea pedis
Clinical manifestations
infected skin scales
Tinea pedis
Mode of transmission
contact with exposed skin via carpet, shower floors, or other shared walking/standing surfaces
Tinea pedis
Disease may progress around the sides of the foot from the sole and is called as?
moccasin foot
Tinea pedis
Characterizations of lesions
minimal scaling, erythema, severly inflamed lesions
Tinea pedis
Treatment
- topical (1 to 6 weeks) or oral antifungals
- imidazole topical cream: once daily for 2 weeks
- interdigital tinea pedis: Naftifine gel or crea m 2% to soles (likelihood of plantar-surface infection)
Infection of the interdigital areas & palmar surfaces
Tinea manuum
T/F: Tinea manuum can affect one or both hands.
True
Tinea manuum
Clinical manifestations
- red raised border with ring appearance (animal or soil fungi)
- dry, peeling, or scaly skin (human fungi)
- tiny blisters that may ooze a sticky, clear fluid
- itching or burning
- skin discoloration (after a long time)
Tinea manuum
Risk factors
- touching skin of someone else
- well-used public shower
- sweating excessively or having another skin condition
- regularly touching pets with hands
- handling livestock or soil
Tinea manuum
Treatment
topical antifungals (Fluconazole, Itraconazole)
This is the invasion of nail plate by dermatophytes
Tinea unguium
Tinea unguium
Appearance
thickened, discolored & brittle
Non dermatophyte
Onychomycosis
Tinea unguium
Risk factors
- diabetees
- disease of small blood vessels
- older women
- wearing of artificial nails
Tinea unguium
Treatment
- Oral terbinafine
- Itraconazole
Anthropophilic, does not invade hair in vivo, worldwide distribution
Epidermophyton floccosum
E. floccosum
Microscopic
smooth thin-walled macroconidia in clusters, growing directly from hyphae
E. floccosum
Microconidia
none but has chlamydoconidia
E. floccosum
Culture
- greenish brown or khaki colored
- suede like surface
- raised and folded center with flat periphery
- yellowish brown reverse pigment
Zoophilic, invades hair and skin, worldwide distribution
Microsporum canis
M. canis
Microscopic
6-12 cells
M. canis
Macroconidia
- thick walled verrucose
- spindle shaped
- spiny surfaces
- curved tip
M. canis
Microconidia
- sparse
- clavate
- sessile
Geophilic, single inflammatory skin or scalp lesion, worldwide distribution
Microsporum gypseum
M. gypseum
Macroconidia
thin walled verrucose
- cigar shaped
- spiny surfaces
- rounded tips
M. canis
Microscopic
- symmetrical ellipsoidal
- distal end slightly rounded, proximal
- 4 to 6 cells
Anthropomorphic, responsible for gray patch tinea capitis
Microsporum audouinii
Zoophilic, inflammatory skin or scalp lesion, ectothrix, worldwide distribution
Trichophyton mentagrophytes
T. mentagrophytes
Microconidia
- spherical
- dense/grape like clusters (en-grappe)
- globose
T. mentagrophytes
Macroconidia
- rare
- cigar-shaped
- coiled spiral hyphae
- smooth thin-walled clavate multiseptate
Anthropophilic, ectothrix or endothrix, worldwide distribution
Trichophyton rubrum
T. rubrum
Microconidia
- clavate/peg/tear shaped
- sessile
T. rubrum
Macroconidia
- pencil shaped
- cylindrical
Anthropophilic, inflammatory or chronic non-inflammatory finely scaling lesions of skin, nails and scalp, worldwide distribution
Trichophyton tonsurans
T. tonsurans
Microconidia
Abundant tear/clun/peg/balloon shaped
T. tonsurans
Macroconidia
Cylindrical
T. tonsurans
Culture
- suede like to powdery
- flat with raised center or folded, with radial grooves
- pale buff to yellow
Anthropophilic, chronic non-inflammatory Tinea corporis, not invade hair
Trichophyton concentricum
