Cutaneous Fungal Infection Flashcards
cutaneous fungal infections affect…
epidermis only
three groups of cute fungi
dermatophytes, malassezia, candida
dermatophytes infect which tissues
keratinized- stratum corneum, nail, hair
cause of tinea pedis
trichophyton rubrum - athletes foot
3 patterns of tinea pedis infection
interdigital- scaling and redness b/w toes maybe w/ maceration (white scale from moist skin)
moccasin-lateral borders of feet, heels, soles; maybe vesicles and erytema at margins or onychomycosis (nail fungal infection)
-maybe hand invovement
vesiculobullous type- grouped vesicles or bullae on arch or instep, can be itchy or painful
-delayed hypersensitivity immune response to dermatophyte
dx of tinea pedis
KOH testing under microscope
tx for tinea pedis
topical antifungals until resolution, then continue for at least 2 weeks
3 topical antifungals
imidazole- fungistatic
allylamines- fungicidal
ciclopirox- cidal and static
complications of tinea pedis
lower leg cellulitis- risk factor is immunocompromise
tinea corporis
onychomycosis and tx
fungal infection of nailbed
poor response to topicals, use oral terbinafine or azoles for 3 months (need to avoid w/ liver problems)
tinea corporis is..
ringworm
dermatophytosis of skin usually trunk and limbs, w/ itching and asymmetric distribution
dx of tinea corporis
KOH scrapings from red scaly margin- active border w/ central clearing
why scrape before steroids?
might be fungal (tinea) rather than inflammatory- could result in tinia incognito and further spread
tx of tinea corporis
topical tx like tinea pedis
oral terbinafine or fluconazole for severe/widespread cases
only need 1-2 weeks when only body or skin
tinea capitis
dermatophytosis of scalp and hair, common in AA children
spread of tinea capitis
direct contact w/ animals, humans, fomites
most common cause is microsporum canis (from animals)
most common in US is trichophyton tonsurans (human to human)
pres of tinea capitis
non inflammatory- black dot (hairs coming out but breaking off at surface), seborrheic
inflammatory- kerion
broken hair, lymphadenopathy in nearby nodes
typically 4-8 yrs
kerion
inflammatory tinia capitis- painful boggy mass w/ broken follicles, can result from untreated tinia capitis
often secondary bacterial infections
risk of scarring
tx of tinea capits
topicals ineffective
griseofulvin is first choice in US
terbinafine has shorter tx course but more hepatotoxicity
involvement of skin folds indicates..
less likely contact dermatitis, more likely infectious
pres of diaper candidiasis
beefy red erosions and margional scaling
satellite papules and pustules
suspect w/ no improvement from zinc oxide pastes
pathogenesis of diaper candidiasis
wet/dirty diapers not changed regularly- urease enzymes in feces
disruption of epidermal barrier allows candida entry
tx of diaper candidiasis
nystatin or imidazole cream or ointment
hydrocortisone maybe w/ major inflammation, limited time
avoid high potency steroids, prevents effective dx testing, KOH can be negative
oral nystatin w/ thrush present, recurrence
other causes of apparent diaper candidiasis
immunodeficiency, zinc deficiency
atopic dermatitis, psoriasis, irritant dermatitis (spares folds), tinea cruris
irritant diaper dermatitis pres
erythema, erosion, spared folds, mainly convex areas
severe cases can show ulcerated papules w/ islands of re epithelizations
tx of irreitant diaper dermatitis
barrier creams like zinc oxide paste
frequent diaper changes, looser fitting
address diarrhea, consider candidiasis
candidal intertrigo- def, dx, pres
infection of large skin folds, warm moist areas
KOH exam show pseudohyphae
more burning than itching
tx of candidal intertrigo
topical antifungals- nystatin, imidazoles
NOT allylamines
prevention: hygiene, dry, weight loss
systemic imidazoles for extensive
examples of dermatophytes
trichophyton, microsporum, epidermophyton
