4. MYCO | P4

dermatophytosis

cutaneous mycosis is also known as ?

ring-like pattern

cutaneous mycosis appear in a ____ pattern

ringworm

dermatophytosis is commonly known as ?

dermatophytes

causative agent of cutaneous mycoses

hair, skin, nails

cutaneous mycoses affects (3)

keratinophilic

dermatophytes love keratin, meaning they are ?

keratinases

dermatophytes produce this enzyme that can break down keratin

37 degrees celcius, serum

dermatophytes are unable to grow at _____ nor in _______

room temperature or 25 degrees celcius

dermatophytes are true molds, meaning they grow best at these temperatures

anthropophilic

geophilic

zoophilic

what are the 3 classifications of dermatophytes

anthropophilic

• present in most humans

• cannot be passed on from infected person to another

Epidermophyton and Trichophyton rubrum

examples of anthropophilic dermatophytes

geophilic

• best survive in soil

Microsporum gypseum

example of geophilic dermatophytes

zoophilic

• thrives on animals

• capable of infecting humans

Microsporum canis, Microsporum nanum, Trichophyton verrucosum

examples of zoophilic dermatophytes

dogs and cats

Microsporum canis affects ?

swine

Microsporum nanum affects ?

horses and swine

Trichophyton verrucosum affects?

skin and nails

Epidermophyton infects these parts

skin, hair, nails

Trichophyton infects these parts

hair or skin

microsporum infects these parts

• contact

• fomites

• trauma

dermatophytosis is acquired through ?

moist

dermatophytes survive well in this environment

immunocompetent individuals

these individuals when infected may have simple treatable infections

immunocompromised individuals

these individuals when infected may have severe infections

re-infection

• when this occurs, it has a much shorter course

• serum growth inhibitors

• c-type lectin receptor

• IL-17 and IFN-y

• transferrin

host defense against dermatophytosis

c-type lectin receptor

responsible for signaling immune response

IL-17 and IFN-y

contributes to antidermatophytic defense and skin inflammation control

transferrin

it is responsible for carrying iron

iron

and important growth requirement for fungal elementsdu

duration and degree

immunity varies in ___ and ___

close human contact

animal to human contact

transmission mode of dermatophytosis is through ?

• sharing clothes

• combs

• brushes

• towels

• bedsheets

close human contact examples

1-2 weeks

incubation period of dermatophytosis

• woods lamp

• dermoscopy

clinical diagnosis for dermatophytosis

green or blue, pink and purple in some

appearance of dermatophytes under woods lamp

epiluminoscopy / epiluminescence microscopy

dermoscopy other names

direct microscopy

laboratory diagnosis for dermatophytes

• skin and nail scraping

• epilated hairs

samples taken for direct microscopy

macro and micro conidia

in direct microscopy, we observe for ?

• fusiform

• +

microsporum

macroconidia -

microconidia -

• clavate

• -

epidermophyton

macroconidia -

microconidia -

• cylindrical, clavate, fusiform

• +, single, clusters

trichophyton

macroconidia -

microconidia -

microsporum

are large multicellular macroconidia with curved or hooked tip

8-15

how many cells are in microsporum

microconidia

microsporum rarely produces ?

trichophyton

these are predominant forms of microconidia

coiled or spiral

hyphae of trichophyton

cannot fluorescence

trichophyton under wood’s lamp

epidermophyton

has macroconidia only

petri dish

traditional culture method

Riddel’s slide culture

done on this culture media because they are not dimorphic fungi

• white cottony surface

• deep yellow reverse

Microsporum canis appearance on culture media

• tan, powdery colony

• yellow with orange brown center on reverse

Microsporum gypseum appearance on culture

• white cottony surface

• deep red non diffusable pigment on reverse

Trichophyton rubrum appearance on culture-

• flat, powdery to velvety

• reddish-brown on reverse

trichophyton tonsurans appearance on culture

cottony to granular

Trichophyton mentagrophytes appearance on culture

trichophyton agar

used for presumptive identification of trichophyton species based on nutritional requirements

none

vitamin requirement for Trichophyton rubrum

thiamine

vitamin requirement for Trichophyton tonsurans and violaceum

thiamine and inositol

vitamin requirement for Trichophyton verrucosum

• flat, velvety, dry colonies

• tan to olive green

Epidermophyton floccosum appearance on culture

• in vitro hair perforation test

• urea hydrolysis

• growth on polished rice grains

• temperature tolerance and enhancement

• PCR

physiological tests done

• epilated hair

• moist filter paper

• 2 weeks for 25 deg celc

in vitro hair perforation test

specimen:

put in a petri dish with ________

incubate for _______ at ________

+: conical hair perforations

skin

where does this clinical manifestation present ?

circular, dry, erythematous, scaly and itchy lesions

hair/scalp - kerion

where does this clinical manifestation present ?

scarring, alopecia, flavus

nail

where does this clinical manifestation present ?

thickened, deformed, discolored, weak, subungual debris accumulation

• tinea pedis

• tinea manuum

• tinea cruris

• tinea inguinum

• tinea corporis

• tinea barbae

• tinea faciei

• tinea capitis

what are the 8 clinical classifications of tinea

athlete’s foot

tinea pedis is commonly known as ?

tinea pedis

• characterized by fissure'/cracks, scales, maceration in the toe web

• there may be also erythema, vesicles and pustules

Trichophyton mentagrophytes

Causative agent of Tinea pedis that can cause blister

Epidermophyton floccosum

causative agent of tinea pedis that affects the whole plantar surface and is often referred to as the “moccasin-type”

tinea manuum

ringworm of the hands

anthropophilic dermatophytes

tinea manuum is most often caused by ?

Trichophyton rubrum

most common causative agent of tinea manuum

jock’s itch

tinea cruris is commonly known as ?

tinea cruris

• the infection of the groin

• characterized by raised red lesions/borders

• mostly seen on adult men, but women can also be infected

• often come from infection of feet or nails

downy and granular

tinea cruris has two stains, namely ?

Trichophyton rubrum

causative agent of Tinea cruris

tinea unguium

onchomycocis or ringworm of the nails

tinea unguium

it is characterized by thickening, discolored and dystrophic nails

Trichophyton rubrum

causative agent of tinea unguium

tinea corporis

the ringworm of the body or simply ringworm

shedding of fungal spores

tinea corporis is spread by the _____ from infected skin

1-3 weeks

incubation period of Tinea corporis

terbinafine

an oral treatment used for tinea corporis that works similar to azoles by inhibiting ergosterol synthesis

itraconazole

terbinafine works well with ?

binds or inhibits a particular enzyme involved in ergosterol synthesis

the difference of terbinafine from azoles is ?

Trichophyton rubrum

causative agent of tinea corporis

Tinea verrucosum

in tinea corporis, this causative agent is usually associated with severe types of ringworm infection

• kerion

• tinea gladiatorum

• tinea imbricata

• tinea incognita

• majocchi’s granuloma

these are the clinical variants of tinea corporis

kerion

• a very large ulcerated lesion

• inflammatory form of Tinea corporis

tinea gladiatorum

• the most common form

• commonly found on individuals in contact sports

tinea imbricata

• characterized by extensive concentric rings

• forms polycylic plaques/lesions with thick scales

• very itchy

tinea incognita

• occurs after taking inappropriate treatment

• most probably because of excessive use of over the counter drug

majocchi’s granuloma

• invasive type

• can infect subcutaneous

• commonly found on the limbs after shaving

Tinea barbae

“barber’s itch”

anthropophilic or zoophilic

tinea barbae is often caused by these type of dermatophytes