Superficial Fungi part 1 Flashcards
conidia
asexual nonmotile spores - reproductive structures
microconidia - trichophyton
macroconidia - microsporum, epidermophyton
sporangia
spores produced in a sac
chlamydoconidia
thick walled round cell
blastoconidia
formed by budding
arthroconidia
formed by fragmentation of hyphae
tinea nigra organism & presentation
hortaea/exophiala werneckii
black yeast-like hyphomycete
hot humid environment
confined to SC (looks like lentigo on foot)
tinea nigra dx and txt
golden brown hyphae on KOH (melanin)
older colonies grayish & filamentous
Rx: keratolytics (whitfield’s ointment), imidazoles
black piedra organism? presentation? location?
piedra hortae
firmly adherent black nodules on hair
tropics, south america
white piedra organism? presentation? culture?
trichosporon beigelii and T. inkin (pubic)
opportunistic - immunosuppressed
tan/white loosely adherent nodules along hair shafts
trichosporanosis organism? presentation?
trichosporon asahii
systemic in immunocompromised
papulovesicular and purpuric lesions w/ necrosis
tinea versicolor organism? cause of depigmentation? dx?
malassezia furfur (pityrosporum orbiculare is yeast phase)
dicarboxylic acid causes depigmentation
KOH: spaghetti and meatballs
wood’s light: yellow-green
malassezia implicated in what neonatal skin condition
neonatal cephalic pustulosis (neonatal acne)
pityrosporum folliculitis
wood’s light: yellow-green
KOH: only yeast seen
monomorphic follicular papules and pustules, often during acne txt (tetracycline casues overgrowth)
women, neck face & trunk
M. furfur and M globosa
fluconazole 400 mg x1 and 2.5% selenium sulfide
how do dermatophytes escape immune system?
mannans
how do dermatophytes infect SC, hair, nails
keratinases
geophilic dermatophytes
mod-severe inflammation Gypspies are Terrible F'ing Cooks M. gypseum (tinea corporis, capitis) T. terrestre M. fulvum M. cookei
dermatophyte nutritional requirements
thiamine (tonsurans, violaceum, verrucosum) histidine (megninii) niacin (equinum) inositol and thiamine (verrucosum) olive oil (m. furfur)
trichophyton
endothrix, no fluorescence
trichophyton
endothrix, no fluorescence
microsporum
ectothrix, +/- fluorescence
microsporum
ectothrix, +/- fluorescence
T. tonsurans
tinea capitis, tinea corporis
granular powdery front and mahogany reverse
pencil shaped swollen microconidia of varying size
cx: need thiamine
T. rubrum
tinea unguium, corporis, capitis
powder puff front, red wine reverse
microconidia lined up like birds on a wire or plucked grape stem
T. tonsurans
tinea capitis, tinea corporis
pencil shaped swollen microconidia of varying size
cx: need thiamine
t. mentagorophytes
zoophilic white wooly front & orange reverse spiral (curly fry) hyphae urease + potato dextrose + hair perforation test + (t. rubrum -)
t. soudanense
right-angle branching hyphae
…39
t. violaceum
…38
t. soudanense
right-angle branching hyphae
…39
t. violaceum
…38
T. rubrum
tinea unguium, corporis, capitis
microconidia lined up like birds on a wire or plucked grape stem
t. verrucosum
cattle…40
t. verrucosum
cattle…40
t. concentricum
tinea imbricata
pacific islands
‘balloon shaped’ chlamydoconidia and antler-like hyphae
t. mentagorophytes
zoophilic spiral (curly fry) hyphae urease + potato dextrose + hair perforation test + (t. rubrum -)
t. shoenleinii
tinea capitis (favus) endothrix favic chandeliers
45
45
m. canis
‘dogs tail’
m. audouinii
grey-tan front, orange salmon reverse. mouse fur
…
tinea capitis types
gray-patch ringworm - microsporum, endothrix
black-dot ringworm - t. tonsurans & t. violaceum, endothrix. do not fluoresce
kerion - m. canis & t. tonsurans. abscess, scarring alopecia, LAD
favus - t. schoenleinii. scutulae sulfur yellow crusts. KOH w/ arthroconidia and airspaces within hair shaft
m. nanum
pigs…
m. gallinae
chickens..
e. floccosum
tinea pedis, cruris
khaki-colored colony w/ orange-brown reverse
club-shaped macroconidia - NO microconidia (also macrosporum)
dermatophyte test medium
dermatophytes produce alkaline = red
nondermatophytes produce acid = yellow
wood’s lamp
365 nm (lost in the woods for a year)
Fluorescent positive infections
Cats And Dogs Fight and Growl Sometimes
tinea capitis organism? presentation?
all trichophyton and microsporum (except t. concentricum and e. floccosum)
MC: t. tonsurans (m. canis mc world-wide)
5-15% urban children asx’ly colonized
can look like seb derm - scrape, alopecia
tinea capitis pathogenesis?
incubation 2-4 days
hyphae descent to form ‘Adamson fringe” - level of keratinization
hair breakage at 3 wks
tinea capitis types
gray-patch ringworm - microsporum, endothrix
black-dot ringworm - t. tonsurans & t. violaceum, endothrix. do not fluoresce
endothrix infections
Say Say Violet..67
tinea capitis txt
griseofulvin, terbinafine with shampoo
treat household contacts (adults are carriers)
tinea barbae
contact w/ farm animals
deep - nodular & suppurative. t mentagrophytes
superficial - crust w/ bald patches. t. violaceum or t rubrum
DOES NOT AFFECT UPPER LIP
tinea faciei
t. rubrum, t. mentagrophytes
upper lip females & children
looks like SLE - it is photosensitive!
can have folliculitis - oral txt
tinea corporis
MCC t. rubrum
Ectothrix organisms
Dogs and Cats Fight Sometimes
