Cutaneous Mycoses

Question 1

Cutaneous Mycoses are caused by a fungi generally called ___? that infect only the keratinized tissues - SKIN, HAIR, and NIALS

Answer 1

Dermatophytes

Question 2

Note:

Dermatophytes

🐈Secrete keratinase-degrades keratin.
🐈Infections extends deep
into the epidermis.
🐈Rarely invade deeper tissue

Answer 2

🐈

Question 3

🐈 Associated with humans only.
🐈 Person -to-person transmission through contaminated
objects (comb, hat, etc.)

🐈Elicit relatively mild and chronic infections
🐈Produce few in conidia in culture

Answer 3

Anthropophilic

Question 3

Ecology of Dermatophytes

To determine the source of infection on??

Answer 3

Anthropophilic
Zoophilic
Geophilic

Question 4

Associated with animals.

Direct transmission to humans by close contact with animals.

Produce more acute inflammatory infections that tend to
resolve quickly

Answer 4

Zoophilic

Question 5

🐈Usually found in soil.
🐈Transmitted to humans by direct exposure.
🐈Produce more acuteinflammatory infections that tend to resolve quickly

Answer 5

Geophilic

Question 6

Three (3) common genera of Dermatophytes

Answer 6

Trichophyton
Miscrosporon
Epidermophyton

Question 7

Trichophyton spp.

-affects the Hair, skin and nails

Answer 7

T. rubrum
T. tonsurans
T. mentagrophytes
T.equinum (horse)
T. verrocosum (cattle)

Question 8

Miscrosporon spp.

• affects the Hair and Skin

Answer 8

🩵M. gypseum (most common)
M. canis (dogs and cats)
M. gallinae (fowl)
M. nanum (pigs)

Question 9

Epidermophyton spp?

-affects the Skin and nails

Answer 9

E. floccosum

Question 10

Most common causative agent of Dermatomycoses

Answer 10

Candida spp

Question 11

Dermatophytes growth req and what medium

Answer 11

Growth for 2 weeks at 250C on Sabouraud’s dextrose agar (SDA)

Question 12

Trichophyton species.

Colonies are cottony to granular

Answer 12

T. mentagrophytes

Question 13

Trichophyton species.

Colonies are white and cottony surface & deep RED non-diffusable pigment

Answer 13

T. rubrum

Question 14

Flat, powdery to velvety colony; reddish brown on reverse

Answer 14

T. tonsurans

Question 15

🩵 Makes both macroconidia and microconidia

Answer 15

T. mentagrophytes

Question 16

globose and in clusters “grapelike” or
engrape

Answer 16

Microconidia

Question 17

thin walled,
smooth and cigar-shaped.

Answer 17

Macroconidia

Question 18

🩵 Produce 4-8 celled cylindrical macroconidia

🩵 Clavate or peg-shaped macroconidia, side of hyphae

Answer 18

T. rubrum

Question 19

appears as “Birds on fence”

Answer 19

T. rubrum

Question 20

🩵Macroconidia are variable in shape

🩵Club-shaped

Answer 20

T. tonsurans

Question 21

Microsporum species spp.

✅Powdery granular colonies
✅Fusiform, moderately thick-walled conidia, rounded tips

Answer 21

Microsporum gypseum

Question 22

✅Fluffy and white colonies with the reverse side forming lemon-yellow pigment

✅Spindle shaped macroconidia with echinulate thick-walled; with tapering spiny distal end.

Answer 22

Microsporum canis

Question 23

-Flat velvety colonies, with tan to olive green tinge

-Produces only macroconidia, smooth walled, clavate 2-4 celled, and formed small clusters
Macroconidia only

Answer 23

Epidermophyton floccosum

Question 24

What mycoses? -Non-hairy, smooth skin -Circular (RING) patches with advancing red, vesiculated border & central scaling, pruritic

Answer 24

Tinea corporis ✅ Trichopyton rubrum ✅ Epidermophyton floccosum

Question 25

Tinea pedis AKA?

Answer 25

(Athletes foot) ✅ Trichopyton rubrum ✅ Trichopyton mentagrophytes ✅ Epidermophyton floccosum

Question 26

Tinea cruris AKA?

Answer 26

“jock itch” - on intertriginous area; pruritic ✅ Trichopyton rubrum, ✅ Trichopyton mentagrophytes ✅ Epidermophyton floccosum

Question 27

Affected are scalp and hair characterized as: ✅ Endothrix: fungus inside hair shaft ✅ Ectothrix: fungus on surface of hair What is the infection called?

Answer 27

🩵Tinea capitis caused by: ✅ Trichopyton mentagrophytes ✅ Trichopyton tonsurans ✅ Microsporum canis

Question 28

- Nail - Nails thickened or crumbling distally; discolored; lusterless. Usually associated with Tinea pedis.

Answer 28

Tinea ungium Trichopyton rubrum, üTrichopyton mentagrophytes üEpidermophyton floccosum

Question 28

- Beard hair - Erythematous lesions

Answer 28

Tinea barbae Trichopyton rubrum, üTrichopyton mentagrophytes üEpidermophyton floccosum

Question 29

Tinea ungium also known as?

Answer 29

Onychomycosis

Question 30

Diagnosis for Cutaneous Mycoses

Answer 30

**Microscopic examination** ✅10-20% Potassium Hydroxide ✅(KOH) ¤ Calcaflour white ✅ Wood’s Light **Culture** ✅ Sabouraud’s agar slants ✅ Mold agar ✅ Incubated for 1-4 weeks at room temperature