Fungal Infections

Question 1

what are the means of which to dx fungal infections?

Answer 1

• potassium hydroxide (KOH)
• culture
• biopsy

Question 2

discuss the proper use KOH preparation

Answer 2

• rub alcohol to site
• use a #15 surgical blade & gently scrape
  
  • if it scales, scrape it!

Question 3

azoles

• MOA
• include what drugs?
• clinical uses of each?
• AEs?

Answer 3

“azoles”

• MOA: demethylation of C14a in of lanasterol, a precursor of ergosteral (steroid in fungal cell walls)
• specific uses:
  
  • fluconazole: all types of candida
  • itraconazole: blasomyces, coccididiodes, histoplasma
  • clotrimazole, miconazole: superficial fungal infections
  • voriconazole, isavuconazole: asperilligus
• adverse effects (AE):
  
  • gynocomastia
  • impotence
  • liver dysfunction

Question 4

which azole has the most severe AEs?

what are they?

Answer 4

ketoconazole

• gynecomastia
• impotence
• liver dysfunction

Question 5

terbinafine

• what kind of drug?
• MOA?
• have what clinical uses?
• have what adverse effects?

Answer 5

• includes: allyamine
• MOA: inhibits squalene epoxidase -> decreases ergosterol
• clinical uses:
  
  • onchomycosis - nail fungus
  • tinea capitis adults - scalp fungus
    
    • griseofulvin m/c used in children*
• adverse effects:
  
  • GI upset
  • liver abnormalities
  • drug induced lupus

Question 6

griseofulvin

• MOA?
• have what clinical uses?
• have what adverse effects?

Answer 6

• MOA: disrupts microtubule formation → inhibiting mitosis
• clinical uses: TOC for tinea capitis in children
• adverse effects (AE): reduces efficacy of
  
  • oral contraceptives
  • warfarin

Question 7

polyenes

• includes what drugs?
• MOA?
• have what clinical uses?
• have what adverse effects?

Answer 7

• includes: nystatin, amphotericin B
• MOA: irreversibly finds to ergosterol -> increasing cell membrane permeability
• clinical uses:
  
  • nystatin: candida infections
    
    • oral candidasis* “swish & swallow”*
    • topical for diaper rash
  • amphotericin B: serious systemic mycosis
• AEs (amphotericin B)
  
  • NEPHROTOXICITY
  • fever/chills + hypotension

Question 8

what does tinea look like on a KOH preparation?

Answer 8

branching, with septate hyphae

Question 9

tinea capitis

• definition
• demographics
• presentation:
• treatment:

Answer 9

• pathogenesis: dermatophyte infection scalp and beard​
  
  • endothrix: arthroconidia on nterior of hair shaft
  • ectothrix: arthroconidia on exterior of hair shaft
• demographics: childhood, M > F
• presentation: scaling, pruritis, eventual -> loss of (hair)
• treatment:
  
  • children: griseofulvin
  • adults: terbinifine

Question 10

kerion

• pathogenesis
• demographics
• presentation
• complications
• treatment

Answer 10

• pathogenesis: tinea capitis that progresses into furuncle
• demographics: farm animal exposure
• presentation: furuncle = painful, boggy, puritic
• complications: may evolve into permanent alopecia so treat early!!
• treatment: steroids ( & griseofulvin?)

Question 11

tinea barbae

• pathogenesis
• demographics
• presentation

Answer 11

• demographics: rare - always ask about farm animal exposure
• presentation: unilateral involvement of the neck + face

Question 12

tinea faciei

• demographics
• presentation
• treatment

Answer 12

• demographics:
  
  • female and children
  • possible hx of animal exposure
• presentation:
  
  • annular configuration + pustules in the border
  • frequently on the upper lip + chin

Question 13

tinea corporis

• pathogenesis
• presentation
• treatment

Answer 13

• pathogenesis: dermatophyte (m/c T. rubum) infects the body/trunk
• presentation: plaques on body / trunk that are
  
  • annular with central clearing
  • scaly
  • have advancing edge
• treatment: azoles
  
  • ​localized - econazole, ketoconazole (topicals)
  • extensive - fluconazole (oral)

Question 14

what can you NOT use to treat tinea corporis?

Answer 14

lotrisone

Question 15

tinea cruris

• demographics
• presentation
• treatment

Answer 15

• demographics: M>F
• presentation: plaques on groin, perineal & perianal skin that are
  
  • party clear in center (but not annular w/ central clearing like corporis)
  • scaly
  • erythematous
• treatment:
  
  • meds: azoles (like corporis)
  • lifestyle: reduce perspiration / moisture + loose fitting clothing

Question 16

how are tinea cruris lesions different differ from tinea corporis lesions?

Answer 16

• both: scaly, erythematous plaques
  
  • corporis: annular with central clearing - on body / trunk
  • cruris: spreads peripherally with moderate clearing in center - on groin, perineum, perianal

Question 17

what distinguish tinea cruris from candidal intertrigo?

Answer 17

• tinea cruris
  
  • spares scotrum
  • plaques with partial central clearing
  • more scaling / less fissuring than c. albicans
• c. albicans
  
  • involves scotum
  • beefy red plaques with satellite lesions
  • more fissuring / less scaling than tinea cruris

Question 18

tinea pedis

• presentation
• diagnosis
• treatment:

Answer 18

• presentation: often “seeded” by onchomycosis
  
  • erythema and desqmation
    
    • interdigital type (m/c): between the toes
    • mocassin type: “two foot + one hand” - often seen with tinea manuum (rash on palmer / interdigital hand)
• diagnosis: KOH - branching, septate hyphae
• treatment: azoles (like corporis, crura)

Question 19

onchomycosis

• pathogenesis
• presentation
• diagnosis
• treatment

Answer 19

• pathogenesis: m/c T. rubum
• presentation: yellow discloration that spreads from distal → proximal
  
  • eventual separation from nail bed
  • subungual hyperkeratosis
• diagnosis: sabaroud agar
• treatment: terbinafine - esp for pts with
  
  • DM
  • perpireral neuropathy

Question 20

discuss the characterics of candida albicans

Answer 20

• growth on sabroud agar
• dimorphic fungi:
  
  • 20 degrees: psuedohyphae + budding yeast
  • 37 degrees: germ tubes
• psuedohyphae at right angles on histopathology

Question 21

candidiasis:

• demographics:
• presentation:
• diagnosis

Answer 21

• demographics: I/C - DM, AIDS, on abx (esp in oral candidasis)
• presentation:
  
  • oral: gray-white membranous plaques that bleed w/ scraping
  • rash (interiginous / vulvovaginitis / diaper): beefy red plaques with satellite lesions + fisssuring
• diagnosis:
  
  • at 20 C: psuedohyphae + budding yeast
  • at 37 C: germ tubes
  • sabraud’s agar: growth
  • histopathology: vertically oriented psuedohyphae

Question 22

oral candidias (thrush)

• demographics
• presentation - gross & clinical
• treatment

Answer 22

• demographics:
  
  • newborns - m/c
  • in children/adults: after Abx course (I/C)
  • in adults with no predisposing factors (no Abx, not I/C): may be first manifestation of AIDS - they need a workup!
• gross presentation: grayish white membranous plaques with red, moist, macerated base
• clinical: metallic taste +/- dysphagia / odynophagia (if esophageal extension, which is m/c in AIDs pts)
• treatment:
  
  • infants: oral nyastatin suspension
  • adults: oral nyastatin suspension OR fluconzole single dose 150 mg

Question 23

perleche (angular chelitis)

• pathogenesis:
• demographics
• presentation

Answer 23

• pathogenesis: C. albicans OR S. aureus
  
  • if S. aureus, “honey colored crust” likely present
• demographics: elderly, due to:
  
  • ill-fitting dentures
  • exaggerated skin folds
  • dry mouth
• presentation: oral commissures have ill-defined, grayish-white thickened areas with erythema (like thrush)

Question 24

candida vulvovaginitis

• demographics
• presentation - gross & clinical
• treatment

Answer 24

• demographics: like oral / interigo - DM, prior Abx, AIDS
• gross: beefy red with satellite lesions + discharge that is thick / white & curd-like
• clinical: severe pruritis + burning
• treatment:
  
  • topical: miconazole, clotrimazole
  • oral: fluconazole 150 mg oral dose

Question 25

paronchyia * pathogenesis * presentation

Answer 25

* pathogenesis: d/t C. albicans OR staph * if acute = s. aureus * if chronic = candida (c for candida) * presentation: **inflammation of nail-fold**

Question 26

candidal intertrigo / diaper candidiasis * presentations * what differential dx to r/o and how

Answer 26

* both: beefy red patches surrounded by satellite lesion**_s_** * **intertrigo: involes scotrum &** **higly fissured** * **​**vs _tinea cruris_: NO SCTORUM, SCALY, LESS FISSURED * **​diaper: involves fold** * ​vs _contact dermatitis:_ SPARES THE FOLDS

Question 27

tinea versicolor * pathogenesis * presentation * diagnosis * treatment

Answer 27

* pathogenesis: ***malassezia globosa*** * demographics: _tropical demographic_ - esp summer months * presentation: macules that are * **hyper OR hypo-pigmented** * **on _upper trunk_** * **scaly, non-blanching and -\> _coalescing_** * diagnosis: * KOH: **short fungae + variably sized spores ("spaghetti and meatballs")** * wood's lamp: **yellow-green** * treatment: * topical: azoles OR selenium sulfied * oralL: fluconazole

Question 28

identify

Answer 28

**tinea versicolor (malassezia)** wood's light examination: yellow-green flourescence KOH prep: spaghetti and meatballs

Question 29

how does tinea versicolor present in council patients?

Answer 29

relapses are common

Question 30

what to NOT use to tx tinea vericolor?

Answer 30

oral ketoconazole

Question 31

sporotrichosis * pathogenesis * presentation * treatment

Answer 31

* pathognenesis: ***sporothrix schenkii:*** * ***​***_dimorphic, cigar shaped budding yeast_ * branching hyphae with _rosettes of conidia_ * demographics: **gardeners** - it lives on vegetations * presentation: **ascending lymphangitis** - **nodules that form along draining lymphatics** * teatment: itraconazole

Question 32

identify

Answer 32

**sporothrix schenckii** - "rose gardeners rash" _dimorphic, cigar shaped yeast_ that grows into -\> branching hyphae with rosettes of conidia

Question 33

which _predisposing factors_ are often present in a adult with oral candidasis? what should you do if these factors are absent? why?

Answer 33

* pt is typically I/C or has had a recent Abx course * if neither of these are the case, patient needs an immediate workup, since their oral thrush may be the _first sign of AIDS_