28 - Overview and Skin Mycoses (Klutts) Flashcards
fungi characteristics
neither plants nor animals
eukaryotic
abundant in nature (air, water, soil)
yeast characteristics
unicellular
round
reproduce by budding
mold characteristics
multicellular
reproduce and grow by hyphae
dimorphic fungi characteristics
exist as either a yeast or mold
structure of fungi
polysaccharide capsule
cell wall
cell membrane
cytoplasm
polysaccharide capsule
outer layer
antiphagocytic (virulence factor)
cell wall
made of chitin, glycan, mannans
antigenic
makes shape, rigidity, strength
cell membrane
phospholipid bilayer
made of ergosterol (target for antifungal)
protects cytoplasm
ways to visualize fungi
KOH (dissolve human cells)
calcofluor white (bind chitin)
GMS (silver stains)
superficial mycoses characteristics
cosmetic problem
no host reaction
easily diagnosed and treated
types of superficial mycoses infections
tinea versicolor
tinea nigra
black piedra
white piedra
tinea versicolor
pityriasis
superficial chronic infection of stratum corneum
tinea versicolor caused and transmitted by
malassezia (furfur or globosa)
human to human
tinea versicolor symptoms
hyper/hypo pigmented maculae
tinea versicolor treatment
topical therapy
tinea versicolor microscopy
spaghetti and meatballs
requires lipid sourced to grow
tinea nigra
superficial chronic infection of stratum corneum
tinea nigra caused by
hortae wernekii
in tropical areas
tinea nigra symptoms
brownish maculae on palms/soles
look like melanoma
diagnosis of tinea nigra
dark pigmented septate with elongated budding
black piedra
fungal infection of hair, hard dark nodules
piedraia hortae
white piedra
fungal infection of hair, loose white nodules
trichosporon species
treatment of black/white piedra
antifungal cream, shampoos, shaving
ringworm
tinea, dermatophytosis
infection of hair, skin, nails caused by dermatophytes (keratinophilic)
ringworm named by
anatomical location
barbae corporis capitis cruris pedis manuum unguinum
beard below eyes above eyes groin feet hands nails
3 genera of dermatophytes
microsporum
epidermophyton
trichophyton
dermatophytes classified by habitat
anthropophilic (humans)
geophilic (soil)
zoophilic (animals)
transmission of dermatophytes
direct human to human
indirect sharing clothes, combs, towels
zoophilic animals to humans
dermatophyte infection symptoms
skin-dry, erythematous, scaly, itchy lesion
hair-scarring, alopecia, favus
nails-thickened, deformed
favus
variant of tinea capitis scutula formation (yellow crusts)
diagnosis of dermatophytosis
clinical appearance
KOH
culture on selective media
treatment of dermatophytes
topical antifungal
oral therapy for tinea capitis, barbae, and nail infections
subcutaneous mycoses characteristics
from trauma or implantation
found in soil/vegetation
difficult to treat
most common subcutaneous mycoses
sporotrichosis
chromoblastomycosis
phaeohyphomycosis
eumycotic mycetoma
sporotrichosis characteristics
chronic infection involving cutaneous, subcutaneous, and **lymphatic tissue
frequently seen in gardeners
**sporothrix schenkii
sporotrichosis symptoms
nodule-ulcer-necrotic ulcer-subcutaneous tissue-lymphatic channels-lymph nodes
sporotrichosis diagnosis
aspriation of fluid/pus KOH Yeast cells in tissue black cigar shaped yeast mycelial form rosette clusters of conidia
chromoblastomycosis characteristics
posttraumatic chronic infection by dematiaceous fungi
found in tropical areas, barefoot
chromoblastomycosis symptoms
papules-warty nodules-verrucous cauliflower like lesions
chromoblastomycosis diagnosis
sclerotic body/medlar body
phaeohyphomycosis characteristics
post traumatic mycotic infection of subcutaneous tissue by dematiaceous fungi
phaeohyphomycosis symptoms
phaeohyphomycotic cyst
phaeohyphomycosis diagnosis
pigmented septate hyphal fragments
mycetoma characteristics
posttraumatic chronic infection of subcutaneous tissue
can extend to fascia, muscle, and tissue
seen in tropical climates
causitive agents of mycetoma
eumycetoma
actinomycetoma
mycetoma symptoms
Abscess formation
draining sinuses containing granules
treatment of subcutaneous infections
surgical excission of lesion
antifungal agents, azoles