Fungal Infections Flashcards
6 types of candidiasis
- generalized cutaneous
- intertrigo
- metastatic skin lesions
- candida folliculitis
- paronychia and onychomycosis
- chronic mucocutaneous candidiasis
4th most commonly isolated pathogen in systemic infection
candidia
3 facts about cadida
adhere well to organisms/cells
have proteases and phospolipids that penetrate and damage cell
can convert to hyphal form “phenotypic switching”
candida is a fungi/yeast? where does it come from
animal->human or in hospital envionments
it is a yeast like fungi
what does candida attack?
host with defect: here are examples:
intact mucocutaneous barriers: wound/iv catheter/burn/ulcer
phagocytic cell:granulocytopenia (increased WBC)
*polymorphonuclear leukocytes-chronic granulomatous disease
monocytic cells-myeloperoxidase deficiency
immunoglobins-hypocomplementemia
cell mediated immunity-chrinuc mucocutaneous candidasis, diabetes mellitus, cyclosporin A, corticosteroids, hiv
mucocutaneous protective bacterial florae-broad spectrum antibiotics
presentation for generalized cutaneous
itchy, diffuse eruption on trunk, extremities
presentation for intertrigo
vesiculopustules in folds and macerations and fissures
scalloped border with white rim consisting of necrotic epidermis
this urrounds red macerated base
satellite lesions
similar to nappy rash
metastatic skin lesions occur in how many cadidiasis cases?
about 10%
candidia folliculitis presents as
candida in hair follicles
paronychia and onychomycosis present as
loss or damage to nail, from immersing hands in water or diabetes mellitus, warm inflammation, tense, glistening, red
chronic mucocutaneous candidiasis presents as
between infant-less then 30 years of age; young ppl or HIV positive
persistent!! disfiguring of face, scalp, hands, nails
oral thrush and vitiligo (blotchy loss of skin color)
associated endocrinologies (hyperparathyroidism,hypothyroidism, addisons disease, DM, auto immune antibodies to gastric tissues*, adrenal, thyroid, Tymomas, dental dysplsia, polyglandular auto immune disease, antibodies to melanin producing cells
candidiasis overall presentation
occurs in women, HIV pts, young people
on torso, extremities, trunk, hair follicles
50% oral colonization
most of us have in fecal
75% of women get it at least 1 time
disease of skin and mucousal membrane of GI GU and respiratory tract
systemic risk factors of candidiasis
*granulocytopenia, bonemarrow transplant, parenternal hyperalimentation, hemotologic malignancies, foley catheter, recent bacterial infection, recent surgery, gi surgery, long hospital stay, severe trauma, burns, acute renal failure, mechanical ventilation more then 3 days, premature birth, broad spectrum ABx, hemodialysis, corticosteroids, chemo radiation, solid neoplasms
Etiology of candidiasis
6 major:
- C. albicans (50-60%)
- C. glabrata -20% are resistant to fluconazol
- C. parapsilosis -vascular catheters
- C. tropicalis - in pts with leukemia and bone marrow transplant
- C. Krusei -intrinsically resistant to ketoconazole, fluconazole and less susceptible to ampotercin B
- C. Lusitanial -intrinsically resistant to amphotercin B
work up candidiasis
mucocutaneous candidiasis:
wetmount / microscope for hyphae, cysts, pseudohyphae, budding yeast cells
KOH prep/gramstain/methylene blue
Culture nail/hair to make sure you are treating the right thing because its a long treatment!
DDx candidiasis
bacterial sepsis, abdominal abscess, asperigillosis
list general tx for candidiasis
- azole antifungals - effect cell membrane
- glucan synthesis inhibitors- effect cell wall
- polyenes - effect cytoplasmic membrane
- allylamine -effect cell wall
more depth tx of candidiasis
- azole antifungals (good for thrush and yeast infection)
type 1: triazoles (3 atoms in ring): fluconazole, itraconzaole, econazole, terconazole, butoconazole, tioconazole
tyle 2: imidazoles (2 atoms in ring):miconazole, ketoconazole, clotrimazole - glucan synthesis inhibitors (less adverse effects/new): caspofungi, micafungi, anidulafungi
- polyenes (broad spectrum)-nystatin (mycostatin), amphotericin B, lipid formulations
- allylamines- less sideeffects! - Terbinafine (daskil, lamisil)
list dermatophyte infections
dermatophytosis
pityriasis versicolor/tinea versicolor
onychomycosis
list types of dermatophytosis
tinea: capitis (scalp) corporis (trunk) manuum/pedi (palm,sole) cruris (groin) barbae(beard) facial (face) unguium (nail)
risk factors for dermatophytosis
moist conditions, communal baths, immunocompromised states, cushing syndrom, athletic activity, atopy, genetic predisposition
dermatophytosis presentation
about 2 weeks from inoculation to see skin changes
itching!!
ID rxns*
ring worm look* (spreads out while center starts to heal)
demarcated*
hair loss (if capitis) brittle hair
exposure to sports-judo karate wrestling etc
3 common causes of dermatophytosis
- T. tonsurans
- M. canis
- T. rumbrum**
hair invasions (tinea capitis) by spore formation (3)
- ectothrix (conidia form on exterior hair shaft and destroy cuticle)
a. microsporums - light up with wood light
b. trichophyton - doesnt light up with wood light - endothrix (conidia are inside hair shaft and cuticle is not effected)
c. trichophyton - doesnt light up with wood light
etiology dermatophytosis
ectothrix spps
endothrix spps
favus spps (in and around hair shaft) - honey combed ** destruction of follicle by Trichophyton schoenlenii
kerion-(thick boggy, spongy plaque/ like seborrehic derm but not inflammed) from bacterial infection- microsporum canis
lupod sycosis/sycosis barbae (barber itch) like kerion- chronic stubborn bacterial infection (impetigo) or folliculitis causing follicular scarring **looks like discoid lupus - **hair areas are more prone to disruptive forms of tinea
dermatophytosis work up
- direct microscopic examination KOH (scrape skin hiar nails and treat with KOH prep - look for hyphae on skin and nails and spores on hair)
- Fungal Culture to ID spps (long tx if wrong)
- wood light examination to diagnose tinea capitis: microsporum audouinni and m. canis will light up but trichophytan schoeleinii wont
dermatophytosis ddx
nummular seborrheic derm syphillis impetgo- bacterial infection alopecia
dermatophytosis tx
- if tinea sorporis:topical ointment and oral antifungals if stubborn case
- if tinea capitis or nail: oral antimycotic drug (topical wont work) must get baseline LFT * checks - check half way thu 3 month tx course - if its a kid get a culture because its a long tx for them as oral
- medication: effects cell wall:
azoles and allylamine
tinea versicolor/pityriasis versicolor presentation
hypo/hyper (hypo is more common) pigmented macules that do not tan
noticed in summer after no symptoms-tan turns u spotty
not usually contagious
superficial and effects melanin
tinea versicolor etiology
M. furfur yeast on human skin
grows in seborrheic areas (scalp face chest)
tinea versicolor work up
koh prep (spaghetti and meatballs)
tinea versicolor ddx
seborrheic derm, tinea corporis, psoriasis guttate
tinea versicolor tx
- selenium sulfide shampoo (neck-waste 15 min-7 days)
- ketoconazole oral pill (dont shower for 18 hours u will sweat it out)
- new imidazole cream/lotions $$$$
onychomycosis definition
fungal infection of nail
6 types of onychomycosis
- distal lateral
- endoyx
- white superficial
- proximal subungual
- total dystrophic
- candidia
presentation of each of the 6 types of onychomycosis
- distal lateral-subungual hyperkeratosis and detachment (onycholysis) yellow/white & painful
- endoyx -milky white nail plate but not damage/detachment to nail
- white superficial -small, white, speckled/powdery patches on surface of nail & roughened nail crumbles easily
- proximal subungual -white spots (leukonychia) on proximal nail plate, periungual inflammation
- total dystrophic - thick, opaque, yellow/brown nail
- candidia - chronic mucocutaeous candidiasis or immunosuppressive with several or all fingers effected by total onychomycosis with
- periungual inflammation with bulbous or drumstick appearance
onychomycosis etiology
- dermatophytes (fungi need keratin) *most common (trichophyton rubrum/ t.mentagrophytes
- non dermatophyte molds
- yeast/candida - rare
onychomycosis work up
osi = severity index -score the disease by area involved
- direct microscopy KOH (rule out fungi)
- cultures -if pt has been off antifungal for more then 2 weeks
- PCR (dna)
- dermoscopy- look for aurora borealis pattern in distal subungual onychomycosis
