Superficial And Cutaneous Mycoses

Front 1

What are the three important genera of the dermatophytes?

Back 1

trichophyton, microsporum, and epidermophyton

Front 2

What do the superficial dermatophytes secrete to obtain food?

Back 2

They secrete keratinase in order to degrade keratin in the skin, hair, and nails as an essential source of food

Front 3

How do all dermatophytes grow?

Back 3

They grow only as septate filamentous fungi

Front 4

How are the three dermatophyte genera able to be differentiated?

Back 4

Based upon the asexual sporulation morphology of their respective conidia

Front 5

Describe the asexual sporulation characteristics of epidermophytons

Back 5

They have club shaped macroconidia and are absent microconidia

Front 6

Describe the asexual sporulation characteristics of micromosporum

Back 6

They have prominent microconidia with a rough-walled, spindle-shpaed macrodonidia

Front 7

Describe the asexual sporulation characteristics of trichophyton

Back 7

They have prominent microconidia with few club or cigar shaped macroconidia

Front 8

What species of dermatophyte secretes a pigment?

Back 8

Microsporum canis secrete a pterdine pigment that flouresces under a Woods lamp

Front 9

What are the possible habitats of dermatophytes?

Back 9

They are commonly found in humans, animals, and the soil

Front 10

What is the most infectious agent of the dermatophytes?

Back 10

The arthrospores, which are very stable on surfaces

Front 11

How are dermatophytes transferred to humans?

Back 11

Direct contact with soil or infected tissue (human or animal) and indirectly via surfaces contamined with highly infectious arthrospores (hairbrushes!)

Front 12

Describe whom dermatophytes can infect and the possible degree of infection (dissemination)

Back 12

Dermatophytes can infect both normal and immunocompromised people, but invasive infection only occurs in the latter

Front 13

What is the most favorable environment for dermatophyte infection?

Back 13

Moist skin surfaces

Front 14

Describe the pathogenesis of a dermatomycosis

Back 14

Arthrospores or conidia germinate and the hyphae invade the keratinized skin

Front 15

Describe the difference between endothirx and exothrix pattern of fungal growth

Back 15

The endothrix pattern shows hyphael growth inside the hair shaft (black dot), while ectothrix pattern grows on the ourer surface of the hair shaft (hair loss)

Front 16

Describe the classic lesion of a dermatomycosis and what is it common called?

Back 16

The lesion is red and scaly with an advancing border and central clearing, commonly called "ringworm"

Front 17

What is tinea capitis?

Back 17

A dermatophyte inefection of the scalp hair and skin seen mainly in children

Front 18

What is tinea faciale?

Back 18

Dermatophyte infection of the face

Front 19

What is tinea barbae?

Back 19

Dermatophyte infection of the mustache, beard area, and neck

Front 20

What is tinea corporis?

Back 20

Dermatophyte infection of the trunk, arms, and legs with classic ringworm lesions

Front 21

What is tinea manuum?

Back 21

Dermatophyte infection of the trunk, arms, and legs

Front 22

What is tinea cruris?

Back 22

Dermatophyte infection of the groin "jock itch"

Front 23

What is tinea pedis?

Back 23

Dermatophyte infection of the soles of the feet called "athlete's foot"

Front 24

What is tinea unguium?

Back 24

Dermatophyte infection of the nails (onychomycosis)

Front 25

What are the most important non-dermatophyte fungi?

Back 25

Malassezia furfur, Hortaea wernekii, Piedraia hortae, Trichosporon

Front 26

What causes pityriasis (tinea) versicolor and what are the clinical manifestations?

Back 26

Malassezia furfur, hyperpigmented macules that coalesce to form scaling plaques

Front 27

What non-dermatophyte fungi are normal flora and what are their locations?

Back 27

Malassezia furfur (skin) and Trichosporon (skin, nails, mouth, and GI tract)

Front 28

What is the cause of tinea nigra? Explain the clinical findings

Back 28

It is caused by hortaea werneckii and is generally asymptomatic but appears as a brown-to-black macule that progressively enlarges

Front 29

What causes black piedra and what are the symptoms?

Back 29

It is caused by piedraia hortae and grows as a filamentous fungus with firmly adhering black/brown nodules on the hair shafts causing breakage

Front 30

What causes white piedra and what are the symptoms?

Back 30

It is caused by the dimorphic yeast trichosporon that infects hair with fungal nodules which are white-light brown and easily removed

Front 31

What fungus is becoming an important opportunistic pathogen and what manifestations does it cause?

Back 31

Trichosporon; it can cause disseminated infections resulting in endocarditis, meningitis, as well as skin manifestations and is resistant to most antifungals

Front 32

What are important factors in the host defense against dermatophyte and non-dermatopyte infection?

Back 32

The acute and chronic inflammation responses help maintain the superficial nature of the infections and the cell-mediated immune response keeps the infections from becoming disseminated

Front 33

What is the most useful method of diagnosis of a superficial or cutaneous fungal infection?

Back 33

Direct microscopic examination of skin scrapings, hair, nails and KOH treatment to degrade keratinized tissue