CHAPTER 15: FUNGI AND YEASTS (SUPERFICIAL) Flashcards
MOA of imidazoles
inhibition of cytochrome P450 14α-demethylase, an sential enzyme in ergosterol synthesis.
MOA of Nystatin
a polyene that works by irreversibly binding to ergosterol, an essential component of fungal cell membranes.
Naftifine, terbinafine, and butenafine are allylamines, and their mode of action is
inhibition of squalene epoxydation.
Black dot ringworm, seborrheic like scaling and inflammatory kerion
This organism in tinea capitis produces spores WITHIN the hair shaft
Do not produce fluorescence in Wood’s lamp
Trichophyton tonsurans
Organism in tinea capitis that produce spores OUTSIDE the hair shaft
Fluoresce under Wood’s lamp
Scaly, erythematous papules with loose and broken off hairs
Microsporum canis
Deep tender boggy plaques exuding pus in tinea capitis
Scarring, permanent alopecia
Kerion celsii
Appears chiefly on scalp but may affect glabrous skin and nails
Scalp- concave yellow sulfur crusts around loose wiry hairs
Atrophic scarring- glossy smooth white patch
Glabrous skin- cup shaped crusts with mousy odor
Favus
Cup shaped crusts usually pierced by a hair on skin with a distinctive mousy odor in tinea infection
Scutulae
Infected tinea hairs will fluoresce what color in Wood’s light?
Bright green or yellow green
Trichophyton- does not fluoresce
Treatment for tinea capitis in children
Griseofulvin 10mg/kg/day
2-4 months
Treatment for trichophyton infections in tinea
Terbinafine 3-6mg/kg/day x 1-4 weeks
Adjunct: selenium sulfide shampoo or ketoconazole shampoo 5 mins 3x a week
vesicular, lichenoid, papulosquamous, or pustular and representing a systemic reaction to fungal antigens.
inflammatory tinea capitis
Id reaction
Tinea barbae is different from staphylococcal folliculitis (sycosis vulgaris) by
Sparing of upper lip
Unilateral involvement
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Circular, sharply circumscribed, slightly erythematous, dry, scaly hypopigmented patches
Progressive central clearing
Found in the body except in face, beard, hands, feet and groin
Tinea corporis
Tx for Tinea corporis
Topical: miconazole , clotrimazole BID x 2-4 wks
Ketoconazole, terbinafine OD
Terbinafine -1 wk
Systemic
Trichophyton: giseofulvin, tebinafine, fluconazole
Deep pustular tinea circinata resembling a carbuncle or kerion on glabrous skin
Follicles distended with purulent ma
Fungal folliculitis
Majocchi granuloma
Tinea incognito is an atypical lesion that are widespread and may lack an advancing scaly border
It is usually caused by
Treatment with topical corticosteroid or calcineurin inhibitors
Infection of the nail plate by a fungus is called
Onychomycosis
Tinea unguium
Onychomycosis caused by what organism?
Starts at distal corner of the nail and involves the junction of the nail and bed
Yellow discoloration, spreads proximally
Nail becomes brittle
T. rubrum
A superficial fungal infection
concentrically
arranged rings or parallel, undulating lines of scales overlapping each other like shingles on a roof (imbrex means “shingle”)
causative fungus is Trichophyton concentricum,
Tinea imbricata (Tokelau)
also known as jock itch and crotch itch
dx: KOH exam, fungal culture, biopsy , immunoflurescence
Tinea cruris
what type of onchomycosis is an indication of an HIV infection?
proximal subungual onchomycosis
caused by T. rubrum and Trichophyton meninii
type of onchomycosis where there is an invasion of the toenail plate on the SURFACE of the nail?
white superficial onchomycosis ( leukonychia trichophytica)
management of onychomycosis
topical: ciclopirox, eficonazole, and amorolfine nail lacquers.
adult with fingernail involvement:
1. terbinafine is given in doses of 250 mg/day for 6–8 weeks. for toenails, 12-16 wks
2. Itraconazole given as pulsed dosing, 200 mg twice daily for 1 week of each month, for 2 months when treating fingernails and for 3–4 months when treating toenails.
3. Fluconazole, 150–300 mg once weekly for 6–12 months, appears to be effective.
Side effect that should be noted when using itraconazole and terbinafine, ketoconazole
liver function abnormalities (alanine transami- nase [ALT], aspartate transaminase [AST], alkaline phospha- tase, total bilirubin).
or development of signs or symptoms suggestive of liver dysfunction.
Grayish white membranous plaques found on the surface of the mucous membrane
Base is moist reddish and macerated
Often first manifestation of AIDS
oral candidiasis (thrush)
Treatment for oral thrush
infants: oral nystatin suspension
adults: clotrimazole, fluconazole
immunocompromised: itraconazole, terbinafine
Maceration and transverse fissuring of the oral commissures
Bilateral involvement
perleche or angular cheilitis
Pruritic intertriginous eruptions between folds
Pink to red moist patches surrounded by a colarette scale
Candidal intertrigo
Candidal intertrigo treatment
topical anticandidal- recurrence is common
topical anticandidal + corticosteroid
castellani paint
Treatment for diaper candidiasis
zinc oxide ointment
oral nystatin
Infection with Candida limited to mucosal surfaces, skin and nails
Onset before 6 years old
Hyperkeratotic, horn like or granulomatous lesions
chronic mucocutaneous candidiasis
Gold standard for systemic candidiasis treatment
Amphotericin B
safer option is liposomal amphotericin
Dark pinhead to pebble sized formations on the hairs of scalp, brows, lashes or beard
Distributed irregularly on the hair shaft
black piedra
Yellow or beige colored soft slimy sheath coating the hair shaft caused by trichosporon
white piedra
Treatment for piedra
- cutting or shaving the hair
- black piedra: Oral and topical terbinafine
- for white piedra: oral itraconazole, topical imidazoles, ciclopirox olamine, 2% sele- nium sulfide, 6% precipitated sulfur in petrolatum, chlorhexi- dine solutions, Castellani paint, zinc pyrithione, amphotericin B lotion, and 2–10% glutaraldehyde
Hypo or hyperpigmented coalescing scaly macules on the trunk and upper arms
Favors oily areas of the skin, occurs during summer
Mild itching and inflammation around patches
tinea versicolor
Treatment for tinea versicolor
- Imidazoles, triazoles, selenium sulfide, ciclopirox olamine, zinc pyrithione, sulfur preparations, salicylic acid prepara- tions, propylene glycol, and benzoyl peroxide have been used successfully as topical agents.
- adults: Oral itraconazole, 200 mg once daily for 7 days; Fluconazole, 400 mg once daily
