Fungal Skin Infections Flashcards
superficial vs subcutaneous vs deep mycosis
superficial: stratum corneum, hair nails
subcutaneous: dermis, subcutaneous tissue
deep: hematogenous spread
most common etiology of tinea
trichophyton rubrum (skin) and trichophyton tonsurans (tinea capitis)
pathogenesis of tinea
- adhesion: adherence of arthroconidia to keratin
- invasion: cell wall inhibit immunity -> invasion and desquamation
- host defense
classification of tinea
body: tinea corporis scalp and hair: tinea capitis face/beard: tinea faciale, tinea barbae hand: tinea manuum foot: tinea pedis groin: tinea cruris nail: tinea unguinum / onychomycosis
classic presentation of tinea corporis
annular plaque with slightly raised, scaly, active, erythematous border
differentials of tinea corporis
- psoriasis: silvery white scales and auspitz sign, fhx
- pityriasis rosea: herald patch, secondary eruption
- tinea versicolor: yellow-green fluorescence in wood lamp, ziti/spaghetti meatballs sign on koh
- nummular eczema: coin-shaped, pinpoint erosions and excoriations
skin findings in non inflammatory tinea capitis
- scales
- arthroconidia form a sheath around hairs
- hairs break off above level of scalp
- wood’s lamp: green fluorescence
skin findings in black dot form of tinea capitis
- hairs break off at level of scalp = grouped black dots within patches of polygonal shaped alopecia
- normal hairs within patches of broken hairs
- diffuse scaling
skin findings in inflammatory tinea capitis
- inflamed, boggy, tender areas of alopecia + follicular pustules to furunculosis
- posterior cervical lymphadenopathy
- zoophilic or geophilic
- negative koh and culture
how to distinguish tinea capitis from seborrheic dermatitis
sd:
- greasy yellowish scaling found in sites rich with sebaceous gland
- no hair loss, no hair breaking!!
how to distinguish tinea capitis from scalp psoriasis
- scales more prominent and readily retained
- hairs not broken and not permanently lost!!
- can involve other body areas
- fhx
most common tinea
tinea pedis
skin findings in interdigital type tinea pedis
- scaling, erythema, and maceration of interdigital skin
- web: dry, scaly and fissured OR white, macerated, and soggy
how to distinguish tinea pedis from erosio interdigitalis blastomycetica
- rf: dm and wet work
- macerated white skin with fissures with raw red bases in web
- macerated skin peels off = painful, raw, denuded area
skin findings in chronic hyperkeratotic moccasin type tinea pedis
patchy or diffuse scaling on soles, lateral and medial aspects of feet
how to differentiate tinea pedis from palmoplantar psoriasis
- thick hyperkeratotic plaques with erythema, fissuring, and scaling
- sterile pustules
- symmetric and involved other body parts
t/f genitalia including the scrotum, are affected in tinea cruris
false, not affected!
skin findings in tinea cruris
well marginated annular plaque with a scaly raised border and central clearing, often bilateral
site: inguinal fold to inner thigh
how to distinguish tinea cruris from erytrasma
- reddish brown, thin, finely wrinkled patches
- uniform appearance, NO CENTRAL CLEARING
- coral red on wood’s lamp
how to distinguish tinea cruris from candidal intertrigo
- beefy red patches with satellite papules and pustules
- WITH SCROTAL INVOLVEMENT
- koh: pseudohyphae and budding yeast
diagnostics for tinea
- koh: long, septated branching hyphae
- culture (sda)
- biopsy: hyphae in stratum corneum
treatment of tinea
- topical
- oral for hair follicles, onychomycosis, or large
- terbinatine, fluconazole itraconazole, griseofulvin
risk factors for chronic paronychia, nail psoriasis, and onychomycosis
read
onychmycosis vs tinea unguium
onychomycosis: fungal infection of the nail due to dermatophytes, non-deramtophyte molds, or yeasts
tinea unguium: dermatophyte infection of the nail
most common form of onychomycosis
distolateral subungual type
nail findings in dlso
- distal nail plate turns yellow/white as hyperkeratotic debris causes nail to rise and separate from underlying bed
- spreads proximally up the nail bed
- dystrophic nail
nail findings in pso
- fungi enter posterior nailfold-cuticle area
- nail separates forming white to beige opacities on proximal nail plate
seen in hiv patients
5ps for sexual history
partners (# and gender) practices protection from stds past history of stds prevention of pregnancy
nail findings in white superficial type onychomycosis
- surface: soft, dry, powdery, can be scraped away
- nail plate: not thickened and remains adherent to nail bed
pathophysio of white superficial type onychomycosis
direct invasion of dorsal nail plate -> white to dull yellow, sharply bordered patches on surface of toenail
how to differentiate onychomycosis and nail psoriasis
- pitting on nail plate surface (ice pick)
- onycholysis
- oil spot lesion
how to differentiate onychomycosis and chronic paronychia
- mild swelling around proximal and lateral nailfolds
- many or all fingers
- candida
- contact irritant exposure
- no subungual thickening!!
diagnosis of onychomycosis
- koh examination (most cost effective)
- culture (most specific)
- nail biopsy with pas exam (most sensitive)
management of onychomycosis
- ciclopirox, amorolfine, tioconazole, efinaconazole
- efina and ciclo 48 wks
risk factors for oral candidiasis
- hiv infection
- infants
- adults
read
type of candidiasis with background erythema with adherent whitish material on oropharyngeal mucosal surfaces, can be brushed off
pseudomembranous form
type of candidiasis: shiny depapillated lingual surface
erythematous atrophic formp
type of candidiasis: maceration and transverse fissuring or crusting at commissures
angular cheilitis
how to distinguish leukoplakia from oral candidiasis
- premalignant for scc
- cannot be brushed off
- hairy leukoplakia
how to distinguish oral lichen planus from oral candidiasis
- buccal mucosa or tongue
- red and smooth with loss of papillae
- nonerosive: dendritic pattern/lacy white network
- erosive: painful; localized or extensive
treatment for oral candidiasis
- oral nystatin
- moderate to severe: oral fluconazole 1-2 wks
- refractory or resistant: itraconazole, posaconazole, voriconazole, amphotericin b
