Superficial, cutaneous and subcutaneous mycoses

Question 1

What is the hallmark of superficial mycoses?

Answer 1

No inflammation/no elicitation of host immune response

Question 2

___ is a superficial mycotic infection (of young folks) caused bylipophilic yeast Malassezia spp. (Malassesia furfur), usually involving upper trunk, neck, and arms

Answer 2

Tinea versicolor

(I got a real nice versicolor fur coat from Malassezia!!)

Also, versi di colore sauce + that woman’s fur coat

Question 3

___ also cause pityriasis folliculitis, seborrheic dermatitis (“dandruff”), and atopic dermatitis

Answer 3

Malassezia spp

Question 4

What do Malassezia spp use as their source of lipids and oils?

Answer 4

Skin and keratin

Question 5

The hallmarks of tinea versicolor infection include:

Answer 5

Non pruritic, has varying color, hyper and hypo-pigmentation

Question 6

Which condition is indicated below and which fungal spp causes it?

Answer 6

Non pruritic, has varying color, hyper and hypo-pigmentation

Skin scraping: delicate septated hyphae and clusters of yeast (spaghetti and meatballs)

Question 7

Which superficial mycosis is characterized by a skin scraping with the presence of delicate septated hyphae and clusters of yeast (spaghetti and meatballs)?

Answer 7

Tinea versicolor

Question 8

What is the treatment for tenia versicolor?

Answer 8

Ketoconazole 2% shampoo

Selenium sulfide suspension 2.5%

Terbinafine solution 1% (spray bottle)

Systemic Rx: Itraconazole or Terbinafine

Systemic Prx: Itraconazole

Question 9

How do you Dx Malassezia infection?

Answer 9

Olive Oil-Supplemented Sheep Blood Agar

Question 10

Which bug is this and what infection does it cause?

Answer 10

Malassezia spp

They look like a shoe print (think of getting a fancy pair of versicolor shoes from Malassezia)

Question 11

What are two differences between cutaneous mycoses and superficial mycoses?

Answer 11

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

Question 12

Name the 3 classes of dermatophytes that cause cutaneous mycoses (hint: MEfT)

Answer 12

Microsporum

Epidermophyton floccosum

Trichophyton spp

(Dermatophytes are so MEfT!)

Question 13

Which fungi are these and what infection do they cause?

Answer 13

Microsporum (dermatophytes) - cause cutaneous mycoses

Have big microconidia and septations within them

Question 14

Which fungus is this?

Answer 14

Tricho has tiny canidia that are transmitted from pt to pt

Also septated hyphae

Tricho has Tiny Canidia!!

Question 15

___ is a dermatophyte infection of the foot

Answer 15

Tenia pedis

Question 16

___ is a dermatophyte infection of the head

Tinea corporis is a dermatophyte infection of the ___

Tinea barbae is a dermatophyte infection of the ___

Answer 16

Tinea capitis- dermatophyte infection of the head

Tinea corporis- dermatophyte infection of the body

Tinea barbae- dermatophyte infection of the beard

Question 17

___ dermatophyte infection of the groin

Tinea unguium- dermatophyte infection of the ___

Tinea ___- dermatophyte infection of the hand

Answer 17

Tinea cruris- dermatophyte infection of the groin

Tinea unguium- dermatophyte infection of the nail

Tinea manuum- dermatophyte infection of the hand

Question 18

What are the characteristic features of dermatophyte infection?

Answer 18

Inflammatory, pruritic, hyper-keratosis eruptions (papulo-squamous eruptions)

Question 19

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?

Answer 19

Pts with iron overload and immunocompromised pts have more severe infections

Cell mediated immunity** (neutrophils not so much)

Question 20

__ is a more severe dermatophyte infection that affects mainly transplant recipients and HIV patients

Answer 20

Majocchi’s granuloma

Question 21

What is the difference between an ectothrix and an endothrix invasion of hair caused by dermatophytes?

Which bugs fall into either category?

Answer 21

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)

Question 22

Which dermatophyte infections are caused by Trichophyton spp (tonsurans)? Microsporum? (canus)

Answer 22

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

Question 23

What infection is caused by Epidermophyton floccosum?

Answer 23

Tinea cruris

Question 24

___ is the most common dermatophytosis, affecting mainly adults and is most commonly caused by Trichophyton rubrum

Which dermatophytosis is mainly seen in children?

Answer 24

Tinea pedis

Tinea capitis - c is for kids

Question 25

Which infection is shown below? Which fungus mainly causes it?

Answer 25

Tinea corporis Mainly Trichophyton spp

Question 26

There are 3 forms of tinea pedis, namely \_\_

Answer 26

Interdigital (just pronounce it fancy) Moccasin (like drinking anything mocca is sin) Vesiculobulluous \*\*may also present with onychomycosis\*\*

Question 27

What infection is this? Which dermatophyte infection is characterized by "black dot" alopechia and formation of a kerion?

Answer 27

Tinea capitis Also tinea capitis

Question 28

How dp you Dx tinea capitis?

Answer 28

KOH prep Culture on Sabouraud dextrose agar with cycloheximide Wood's light examination (M canis = blue green)

Question 29

What is the Rx for tenia capitis?

Answer 29

**terbinafine (systemic)** azoles griseofulvin **Ketoconazole (topical to reduce fungal shedding)**

Question 30

What is the Rx for the following infections? Tinea pedis, tinea corporis, tinea cruris, tinea manuum

Answer 30

Topical rx most common: **miconazole and clotrimazole**; can use oral therapy if most of trunk is covered **(terbinafine)**

Question 31

\_\_\_ is an infection of the nail plate and/or nail bed that interferes with normal nail function

Answer 31

Onychomycosis

Question 32

The main causes (fungi) of onychomycosis are \_\_

Answer 32

**T. rubrum** and T. mentagrophytes var. interdigitale (rubrum is almost like rubio as in the politician marco rubio)

Question 33

There are 3 forms of onychomycosis, namely\_\_

Answer 33

proximal subungual (PSO), distal subungual (DSO) white superficial (WSO) (Onychomycosis is PDW!)

Question 34

Of the forms of onychomycosis, which is the most common and what is the mechanism of infection?

Answer 34

DSO most common **( T rubrum)** fungi enter distally \>\> spread proximally \>\> eat nail bed + plate \>\> subungual hyperkeratosis, paronychia, onycholysis

Question 35

Which type of onychomycosis is this?

Answer 35

DSO

Question 36

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?

Answer 36

PSO via T rubrum

Question 37

What is the mechanism of invasion in PSO?

Answer 37

Fungi enter proximally @ cuticle\>\> eat nail bed \>\> spread distally\>\> if left un-Rx, will eventually eat nail plate

Question 38

Which type of onychomycosis is this?

Answer 38

**PSO**; Cuticle damaged, base of nail bed also damaged

Question 39

Which type of onychomycosis involves extensive exposure to water and results in attack of the dorsal surface of the nail plate and minimal inflammation?

Answer 39

WSO Caused by T. mentagrophytes.

Question 40

How do you Dx onychomycosis?

Answer 40

Dx: KOH prep + culture of nail

Question 41

What is the Rx for onychomycosis?

Answer 41

Rx: systemic (terbinafine or itraconazole)

Question 42

An example of subcutaneous mycosis is __ (disease)

Answer 42

Lymphocutaneous sporotrichosis or fixed sporotrichosis

Question 43

Lymphocutaneous sporotrichosis typically results from \_\_\_

Answer 43

Introduction of spores via trauma from wooded plants (or exposure to thorn, like when gardening)

Question 44

Which infection is this?

Answer 44

Fixed cutaneous sporotrichosis

Question 45

Which infection is this?

Answer 45

Lymphocutaneous sporotrichiosis

Question 46

How do you Dx sporotrichosis?

Answer 46

Biopsy Culture

Question 47

How do you treat sporotrichosis?

Answer 47

Itraconazole Terbinafine

Question 48

Which subcutaneous mycosis is characterized by plaque-like, papular, and verrucous lesions, and **muriform cells**?

Answer 48

Chromoblastomycosis \*\*Typically in agricultural workers\*\*

Question 49

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)?

Answer 49

Mycetoma | (caused by **Pseudallescheria**)