SUPERFICIAL MYCOSES

Question 1

What are the four clinical classifications of mycoses?

Answer 1

Superficial (cutaneous) mycoses, Subcutaneous mycoses, Systemic mycoses, Opportunistic mycoses

Question 2

What is a mycosis?

Answer 2

A disease caused by fungi

Question 3

Which type of mycosis affects only the outermost layer of the skin or hair?

Answer 3

Superficial mycosis

Question 4

Which type of mycosis affects internal organs without involving the skin or deeper tissues?

Answer 4

Systemic mycosis

Question 5

What type of fungi are capable of degrading keratin?

Answer 5

Dermatophytes

Question 6

What is the causative agent of tinea versicolor?

Answer 6

Malassezia furfur

Question 7

What is the laboratory appearance of Malassezia furfur under KOH preparation?

Answer 7

“Spaghetti and meatballs” appearance

Question 8

What fungal species causes black piedra?

Answer 8

Piedraia hortae

Question 9

What is a characteristic clinical sign of Hortaea werneckii infection?

Answer 9

Brown to black non-scaly macules on palms and soles

Question 10

What fungal species causes white piedra?

Answer 10

Trichosporon spp.

Question 11

Which Trichosporon species is a human pathogen?

Answer 11

Trichosporon beigelii

Question 12

Which Trichosporon species is associated with fatal disease in immunocompromised hosts?

Answer 12

Trichosporon asahii

Question 13

What does the term “keratinophilic” mean?

Answer 13

Ability to utilize keratin as a nitrogen source

Question 14

What are the three genera of dermatophytes?

Answer 14

Trichophyton, Microsporum, Epidermophyton

Question 15

Which dermatophyte genus affects hair, skin, and nails?

Answer 15

Trichophyton

Question 16

What type of dermatophyte infection is most commonly caused by Trichophyton species?

Answer 16

Tinea corporis (ringworm of the body)

Question 17

What is the preferred host of anthropophilic dermatophytes?

Answer 17

Humans (anthropophilic = “human loving”)

Question 18

What two stains are commonly used to detect dermatophytes in clinical specimens?

Answer 18

Calcofluor white or potassium hydroxide (KOH) stain

Question 19

What fungal structures do these stains reveal?

Answer 19

Hyaline septate hyphae or arthroconidia

Question 20

What are the two types of hair infections caused by dermatophytes?

Answer 20

Endothrix (spores fill the hair shaft) and Ectothrix (spores ensheath the hair shaft)

Question 21

What is the common name for Tinea cruris?

Answer 21

Jock itch (ringworm of the groin)

Question 22

What is the common name for Tinea capitis?

Answer 22

Ringworm of the scalp and hair

Question 23

What is the common name for Tinea unguium?

Answer 23

Ringworm of the nails

Question 24

What is the common name for Tinea barbae?

Answer 24

Ringworm of the beard

Question 25

What is the common name for Tinea pedis?

Answer 25

Athlete’s foot (ringworm of the feet)

Question 26

Which Trichophyton species is associated with Tinea favosa and produces antler hyphae?

Answer 26

T. schoenleinii

Question 27

Which Trichophyton species is slow-growing, a common nail dermatophyte, and has a white downy or pink granular colony?

Answer 27

T. rubrum

Question 28

Which Trichophyton species has grapelike clusters of microconidia and infects nails?

Answer 28

T. mentagrophytes

Question 29

Which Trichophyton species is larger than other dermatophytes and has balloon-shaped microconidia?

Answer 29

T. tonsurans

Question 30

Which Trichophyton species produces port wine to deep violet colonies and has chlamydoconidia aligned in chains?

Answer 30

T. violaceum

Question 31

Which Microsporum species is the primary cause of Tinea capitis?

Answer 31

M. audouinii

Question 32

What is the characteristic macroconidia shape of Microsporum species?

Answer 32

Echinulate, spindle-shaped, thick-walled macroconidia with four or more septa

Question 33

What is the preferred host of Microsporum canis?

Answer 33

Animals (zoophilic)

Question 34

What is the most common cause of ringworm in dogs?

Answer 34

Microsporum canis

Question 35

What are common clinical signs of a dermatophyte infection?

Answer 35

Circular, scaly patches, alopecia, low-grade superficial lesions

Question 36

What is the characteristic appearance of “black dot” ringworm?

Answer 36

Hair breakage at the scalp, leaving black dots

Question 37

How is Tinea capitis commonly transmitted?

Answer 37

Contaminated caps, hats, combs

Question 38

Which Microsporum species is commonly transmitted through contact with infected animals?

Answer 38

Microsporum canis

Question 39

What type of environment does Microsporum gypseum thrive in?

Answer 39

Soil (geophilic dermatophyte)

Question 40

Which laboratory test is used to detect fluorescence in infected hairs?

Answer 40

Wood’s lamp

Question 41

What staining techniques can be used to visualize dermatophytes in clinical specimens?

Answer 41

Calcofluor white stain or potassium hydroxide (KOH) prep

Question 42

What is the microscopic characteristic of Microsporum canis macroconidia?

Answer 42

Tapering, spiny distal ends

Question 43

What is the microscopic characteristic of Microsporum gypseum macroconidia?

Answer 43

Fusiform, thick-walled conidia

Question 44

What is a key feature of Epidermophyton floccosum macroconidia?

Answer 44

Thin-walled, multiseptate, rounded tip

Question 45

What color fluorescence does Microsporum canis exhibit under a Wood’s lamp?

Answer 45

Yellow-green fluorescence

Question 46

What is the colony appearance of Microsporum canis?

Answer 46

Cottony white to salmon-colored with velvety aerial mycelium

Question 47

What is the colony appearance of Microsporum gypseum?

Answer 47

Lemon-yellow or yellow-orange fringe

Question 48

What is the colony appearance of Epidermophyton floccosum?

Answer 48

Powdery surface, buff or cinnamon color, brownish underside

Question 49

How does Epidermophyton floccosum respond to cold temperatures?

Answer 49

Susceptible to cold, slow-growing