Fungal infections of skin and soft tissue

Question 1

What are the superficial mycoses?

Answer 1

Pityriasis versicolor, tinea nigra, black piedra, white piedra

Question 2

What is the cause of pityriasis versicolor?

Answer 2

Malassezia furfur

Question 3

Where is pityriasis versicolor normally found?

Answer 3

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

Question 4

What are the clinical symptoms of pityriasis versicolor?

Answer 4

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

Question 5

What is the diagnosis for pityriasis versicolor?

Answer 5

Direct observation - KOH prep (“spaghetti and meatballs”)

Question 6

What is the cause of tinea nigra?

Answer 6

Exophiala werneckii

Question 7

How is tinea nigra transmitted?

Answer 7

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

Question 8

What is the clinical presentation of tinea nigra?

Answer 8

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

Question 9

How is tinea nigra diagnosed?

Answer 9

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

Question 10

Where is black piedra most common? White piedra?

Answer 10

1. Black - tropics 2. White - southern US

Question 11

What are the clinical symptoms of black piedra?

Answer 11

Hard, firmly attached gritty nodules on hair, primarily scalp

Question 12

What are the clinical symptoms of white piedra?

Answer 12

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

Question 13

What is the cause of cutaneous mycoses?

Answer 13

Dermatophytes

Question 14

What are the three most clinically relevant dermatophytes?

Answer 14

Microsporum, trichophyton, epidermophyton

Question 15

What do the dermatophytes use as a nutrient source?

Answer 15

Keratin

Question 16

What is used to treat tinea capitis?

Answer 16

Griseofulvin

Question 17

Candida exists in which form in normal flora?

Answer 17

Yeast

Question 18

Candida exists in which form in tissues?

Answer 18

Hyphal

Question 19

What is the recommended treatment for disseminated candidiasis?

Answer 19

IV amphotericin B with or without fluconazole

Question 20

What are the subcutaneous mycoses?

Answer 20

Sporotrichosis, chromoblastomycosis, mycetoma

Question 21

How is sporotrichosis transmitted?

Answer 21

Traumatic inoculation via rose thorns, wood splinters, sphagnum moss

Question 22

What are the clinical symptoms of sporotrichosis?

Answer 22

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

Question 23

How is sporotrichosis diagnosed?

Answer 23

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

Question 24

How is sporotrichosis treated?

Answer 24

Oral potassium iodide, oral azoles (sever)

Question 25

How is chromoblastomycosis transmitted?

Answer 25

Traumatic inoculation of darkly pigmented soil fungi

Question 26

What is the clinical symptoms of chromoblastomycosis?

Answer 26

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

Question 27

What are Medlar bodies?

Answer 27

Copper colored spherical cells seen in tissues during chromoblastomycosis infection

Question 28

What is the diagnosis for chromoblastomycosis?

Answer 28

Brown pigmented hyphae in skin scrapings and presence of Medlar bodies

Question 29

What is the replicating form of chromoblastomycosis?

Answer 29

Medlar bodies

Question 30

What is the treatment for chromoblastomycosis?

Answer 30

Surgical removal, 5-fluorocytosine

Question 31

How is mycetoma transmitted?

Answer 31

Traumatic inoculation of soil-inhabiting fungi

Question 32

What is the clinical syndrome associated with mycetoma?

Answer 32

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

Question 33

What is the diagnosis for mycetoma?

Answer 33

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