Fungal infections of skin and soft tissue Flashcards Preview

Year 1 Microbiology > Fungal infections of skin and soft tissue > Flashcards

Flashcards in Fungal infections of skin and soft tissue Deck (33):
1

What are the superficial mycoses?

Pityriasis versicolor, tinea nigra, black piedra, white piedra

2

What is the cause of pityriasis versicolor?

Malassezia furfur

3

Where is pityriasis versicolor normally found?

Areas of the body rich in sebaceous glands (head, trunk, upper back)

4

What are the clinical symptoms of pityriasis versicolor?

Numerous irregularly shaped yelllow / brown scaly patches; failure to tan

5

What is the diagnosis for pityriasis versicolor?

Direct observation - KOH prep ("spaghetti and meatballs")

6

What is the cause of tinea nigra?

Exophiala werneckii

7

How is tinea nigra transmitted?

Traumatic inoculation / contamination with soil, sewage, wood, compost

8

What is the clinical presentation of tinea nigra?

Distinct oval-shaped brown/black lesions on hands and feet

9

How is tinea nigra diagnosed?

KOH prep on skin scrapings reveal two-celled yeast forms containing dark pigment

10

Where is black piedra most common? White piedra?

1. Black - tropics 2. White - southern US

11

What are the clinical symptoms of black piedra?

Hard, firmly attached gritty nodules on hair, primarily scalp

12

What are the clinical symptoms of white piedra?

Soft, loosely attached white / light brown nodules usually on pubic or axillary hair, beards, eyebrows

13

What is the cause of cutaneous mycoses?

Dermatophytes

14

What are the three most clinically relevant dermatophytes?

Microsporum, trichophyton, epidermophyton

15

What do the dermatophytes use as a nutrient source?

Keratin

16

What is used to treat tinea capitis?

Griseofulvin

17

Candida exists in which form in normal flora?

Yeast

18

Candida exists in which form in tissues?

Hyphal

19

What is the recommended treatment for disseminated candidiasis?

IV amphotericin B with or without fluconazole

20

What are the subcutaneous mycoses?

Sporotrichosis, chromoblastomycosis, mycetoma

21

How is sporotrichosis transmitted?

Traumatic inoculation via rose thorns, wood splinters, sphagnum moss

22

What are the clinical symptoms of sporotrichosis?

Inflammation at site of inoculation followed by development of painless granulomatous lesion which eventually ulcerates to create an open sore

23

How is sporotrichosis diagnosed?

Cultivation from tissue or pus - mold converts to yeast form at 37 C

24

How is sporotrichosis treated?

Oral potassium iodide, oral azoles (sever)

25

How is chromoblastomycosis transmitted?

Traumatic inoculation of darkly pigmented soil fungi

26

What is the clinical symptoms of chromoblastomycosis?

Initially presents as a wart like lesion and slowly develops to red/gray cauliflower like lesion (painless)

27

What are Medlar bodies?

Copper colored spherical cells seen in tissues during chromoblastomycosis infection

28

What is the diagnosis for chromoblastomycosis?

Brown pigmented hyphae in skin scrapings and presence of Medlar bodies

29

What is the replicating form of chromoblastomycosis?

Medlar bodies

30

What is the treatment for chromoblastomycosis?

Surgical removal, 5-fluorocytosine

31

How is mycetoma transmitted?

Traumatic inoculation of soil-inhabiting fungi

32

What is the clinical syndrome associated with mycetoma?

Slow growing papule at site of infection that ulcerates to release pus and blood - underlying bone becomes involved to create pitted lesions

33

What is the diagnosis for mycetoma?

Direct observation of colored "grains" in pus, tissue, or discharge - compacted hyphae and conidia