Skin fungal infections

Question 1

Malassezia spp (furfur, globosa)

Answer 1

-Tinea (pityriasis) versicolor
Morph: “spaghetti and meat balls” = yeast cells mixed with hyphae
Epid: tropical and subtropics / young adults / PTP xsmission
CP: hyper/hypo pigmentation of torso and arms
Dx via visualization from KOH treated sample
Tx with topical azoles

Question 2

Hortaea werneckii

Answer 2

-Tinea nigra
Morph: black mold / freq breaching hyphae
Epid: tropics and subtropics / children and females
CP: brown/black macular lesions on palms and soles
-Dx via visualization w/ KOH treated sample
-Tx with topical azoles and Whittfield ointment

Question 3

Trichosporon spp (beigelii, inkin)

Answer 3

-White piedra
Morph: hyphae w/ athroconidia and blastoconidia
Epd: tropics and subtropics / poor hygiene
CP: yellow/white granules on hair shafts; look like lice
Dx via visualization; will culture as dry cream colored colonies
Tx with improved hygiene

Question 4

Piedraia hortae

Answer 4

-Black piedra
Morph: brown-black mold w/ hyphae and spindle shaped acospores
Epid: tropics and subtropics / poor hygiene
CP: dark nodules on hair shafts
Dx via visualization
Tx with improved hygiene

Question 5

Dermatophytes (Trichophyton, epidermophyton, Microsporum)

Answer 5

-Cutaneous mycoses (dermatophytoses)
Morph: filamentous that form macro or microconidia
-anthropophilic dermatophytes are hard to cure
-CP: “ring worm”; viable fungi are at perimeter of ring; spreads through stratum corneum
-dz named for part of body affected
-Dx via KOH treated sample
Tx with azoles or nail lacquers for onychomycosis

Question 6

Sporothrix schenkii

Answer 6

-Sporotrichosis / rose picker’s disease
Morph: melanin containing dimorphic conidia = hyphae at 25deg and yeast at 35deg
CP: nodule at site of inf / lymph spread to create other nodules
Dx via culture
Tx with oral saturated potassium iodide

Question 7

Cladosporium carrionii, Fonsecaea spp, Phialophora verrucosa

Answer 7

Chromoblastomycosis
Morph: dematiaceous molds; form brown muriform cells (sclerotic or medlar bodies)
Epid: rural tropics; rainfall influences dom species
CP: wart-like lesions on feet and legs –> cauliflower like growths –> may progress to elephantiasis
Dx via H&E of scrapings
Tx with antifungals is limited and surgical resection is not indicated

Question 8

Fusarium spp, Curvularia spp, Scedosporium spp

Answer 8

Eumycotic mycetoma
Morph: mixed hyphae and chlamydoconidia in hard cement-like material
Epid: tropics with low rainfall
CP: granulomatous nodules on feet and hands –> chronic inflammation and fibrosis -> sinus tracts w/ local muscle and bone destruction
Dx with H&E from sinus tract sample
Tx is most unsuccessful