Superficial, cutaneous and subcutaneous mycoses Flashcards
What is the hallmark of superficial mycoses?
No inflammation/no elicitation of host immune response
___ is a superficial mycotic infection (of young folks) caused bylipophilic yeast Malassezia spp. (Malassesia furfur), usually involving upper trunk, neck, and arms
Tinea versicolor
(I got a real nice versicolor fur coat from Malassezia!!)
Also, versi di colore sauce + that woman’s fur coat
___ also cause pityriasis folliculitis, seborrheic dermatitis (“dandruff”), and atopic dermatitis
Malassezia spp
What do Malassezia spp use as their source of lipids and oils?
Skin and keratin
The hallmarks of tinea versicolor infection include:
Non pruritic, has varying color, hyper and hypo-pigmentation
Which condition is indicated below and which fungal spp causes it?
Non pruritic, has varying color, hyper and hypo-pigmentation
Skin scraping: delicate septated hyphae and clusters of yeast (spaghetti and meatballs)
Which superficial mycosis is characterized by a skin scraping with the presence of delicate septated hyphae and clusters of yeast (spaghetti and meatballs)?
Tinea versicolor
What is the treatment for tenia versicolor?
Ketoconazole 2% shampoo
Selenium sulfide suspension 2.5%
Terbinafine solution 1% (spray bottle)
Systemic Rx: Itraconazole or Terbinafine
Systemic Prx: Itraconazole
How do you Dx Malassezia infection?
Olive Oil-Supplemented Sheep Blood Agar
Which bug is this and what infection does it cause?
Malassezia spp
They look like a shoe print (think of getting a fancy pair of versicolor shoes from Malassezia)
What are two differences between cutaneous mycoses and superficial mycoses?
Superficial: stays on stratum corneum (most superfical layer) and DOES NOT elicit host immune response
Cutaneous: Involves epidermis and dermis and evokes an inflammatory reaction in the host
Name the 3 classes of dermatophytes that cause cutaneous mycoses (hint: MEfT)
Microsporum
Epidermophyton floccosum
Trichophyton spp
(Dermatophytes are so MEfT!)
Which fungi are these and what infection do they cause?
Microsporum (dermatophytes) - cause cutaneous mycoses
Have big microconidia and septations within them
Which fungus is this?
Tricho has tiny canidia that are transmitted from pt to pt
Also septated hyphae
Tricho has Tiny Canidia!!
___ is a dermatophyte infection of the foot
Tenia pedis
___ is a dermatophyte infection of the head
Tinea corporis is a dermatophyte infection of the ___
Tinea barbae is a dermatophyte infection of the ___
Tinea capitis- dermatophyte infection of the head
Tinea corporis- dermatophyte infection of the body
Tinea barbae- dermatophyte infection of the beard
___ dermatophyte infection of the groin
Tinea unguium- dermatophyte infection of the ___
Tinea ___- dermatophyte infection of the hand
Tinea cruris- dermatophyte infection of the groin
Tinea unguium- dermatophyte infection of the nail
Tinea manuum- dermatophyte infection of the hand
What are the characteristic features of dermatophyte infection?
Inflammatory, pruritic, hyper-keratosis eruptions (papulo-squamous eruptions)
Patients with what 2 conditions are especially at risk for more severe dermatophyte infections?
What component of the host immune response is responsible for the tissue damage seen in dermatophyte infections?
Pts with iron overload and immunocompromised pts have more severe infections
Cell mediated immunity** (neutrophils not so much)
__ is a more severe dermatophyte infection that affects mainly transplant recipients and HIV patients
Majocchi’s granuloma
What is the difference between an ectothrix and an endothrix invasion of hair caused by dermatophytes?
Which bugs fall into either category?
Ectothrix (M canis):
Causes tenia capitis
Bug cuts hair down and leaves an intact bulb but destroys external surface of hair shaft
Endothrix infection
T tonsurans – anthropophilic so its adapted to host response (host response becomes limited) and don’t clip the hair shaft externally but instead destroy the bulb of the hair (note that this is a disease in kids) – causes permanent alopechia
(most common cause in urban settings of tenia capitis)
Which dermatophyte infections are caused by Trichophyton spp (tonsurans)? Microsporum? (canus)
Trichophyton spp: Tinea capitis, tinea barbae, tinea corporis, tinea cruris, tinea pedis, and tinea unguium
Microsporum spp: tinea capitis, tinea corporis, tinea cruris, and tinea pedis, but not tinea unguium
What infection is caused by Epidermophyton floccosum?
Tinea cruris
___ is the most common dermatophytosis, affecting mainly adults and is most commonly caused by Trichophyton rubrum
Which dermatophytosis is mainly seen in children?
Tinea pedis
Tinea capitis - c is for kids
Which infection is shown below? Which fungus mainly causes it?
Tinea corporis
Mainly Trichophyton spp
There are 3 forms of tinea pedis, namely __
Interdigital (just pronounce it fancy)
Moccasin (like drinking anything mocca is sin)
Vesiculobulluous
**may also present with onychomycosis**
What infection is this?
Which dermatophyte infection is characterized by “black dot” alopechia and formation of a kerion?
Tinea capitis
Also tinea capitis
How dp you Dx tinea capitis?
KOH prep
Culture on Sabouraud dextrose agar with cycloheximide
Wood’s light examination (M canis = blue green)
What is the Rx for tenia capitis?
terbinafine (systemic)
azoles
griseofulvin
Ketoconazole (topical to reduce fungal shedding)
What is the Rx for the following infections?
Tinea pedis, tinea corporis, tinea cruris, tinea manuum
Topical rx most common: miconazole and clotrimazole; can use oral therapy if most of trunk is covered (terbinafine)
___ is an infection of the nail plate and/or nail bed that interferes with normal nail function
Onychomycosis
The main causes (fungi) of onychomycosis are __
T. rubrum and T. mentagrophytes var. interdigitale
(rubrum is almost like rubio as in the politician marco rubio)
There are 3 forms of onychomycosis, namely__
proximal subungual (PSO),
distal subungual (DSO)
white superficial (WSO)
(Onychomycosis is PDW!)
Of the forms of onychomycosis, which is the most common and what is the mechanism of infection?
DSO most common ( T rubrum)
fungi enter distally >> spread proximally >> eat nail bed + plate >> subungual hyperkeratosis, paronychia, onycholysis
Which type of onychomycosis is this?
DSO
Which type of onychomycosis occurs in imunocompromised hosts and is thought to be an early indicator of HIV infection or other severe impairment of cell mediated immunity?
PSO via T rubrum
What is the mechanism of invasion in PSO?
Fungi enter proximally @ cuticle>> eat nail bed >> spread distally>> if left un-Rx, will eventually eat nail plate
Which type of onychomycosis is this?
PSO; Cuticle damaged, base of nail bed also damaged
Which type of onychomycosis involves extensive exposure to water and results in attack of the dorsal surface of the nail plate and minimal inflammation?
WSO
Caused by T. mentagrophytes.
How do you Dx onychomycosis?
Dx: KOH prep + culture of nail
What is the Rx for onychomycosis?
Rx: systemic (terbinafine or itraconazole)
An example of subcutaneous mycosis is __ (disease)
Lymphocutaneous sporotrichosis or fixed sporotrichosis
Lymphocutaneous sporotrichosis typically results from ___
Introduction of spores via trauma from wooded plants (or exposure to thorn, like when gardening)
Which infection is this?
Fixed cutaneous sporotrichosis
Which infection is this?
Lymphocutaneous sporotrichiosis
How do you Dx sporotrichosis?
Biopsy
Culture
How do you treat sporotrichosis?
Itraconazole
Terbinafine
Which subcutaneous mycosis is characterized by plaque-like, papular, and verrucous lesions, and muriform cells?
Chromoblastomycosis
**Typically in agricultural workers**
Which subcutaneous mycosis is characterized by the invasion of muscle, tendon and bone with draining sinus tracks (its like actinomycosis with sulfure granules except caused by fungi)?
Mycetoma
(caused by Pseudallescheria)
