Superficial and Cutaneous Mycoses Flashcards Preview

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Flashcards in Superficial and Cutaneous Mycoses Deck (49):
1

What causes mycoses

Yeasts for the most part

2

What causes Pityriasis Versicolor

Malassezia Furfur

3

What does Pityriasis Versicolor look like

Hypo or hyper pigmented macules on chest, neck, back

4

What immune responses do we typically see to Superficial Mycoses?

Little to no immune response

5

Where do superficial mycoses colonize?

Outer keratinized surface of skin, hair, or nails

6

What causes dandruff?

Malessezia Globosa

7

How do we diagnose a superficial mycosis?

Direct visualization of yeast-like cells and short branched pseudohyphae.

8

Treatment for superficial mycosis?

Topical therapy, olive oil, single dose oral azole if widespread

9

What makes a cutaneous mycosis different from a superficial one BASICALLY?

Cutaneous involves invasion of the epidermis with an inflammatory response. They break down keratin after invading the stratum corneum.

10

What primarily causes cutaneous mycoses?

Mold dermatophytes such as trichophyton, epidermophyton, and microsporum

11

What does microsporum typically cause?

Athlete's foot, jock itch, ringworm

12

Tinea infections

Latin for "worm"

Caused by dermatophytes. Result in inflammatory scaling often in the pattern of an expanding circle or ring with frequent hair loss

13

Tinea capitis

Tinea infection of the head

14

Tinea Coporis

Trunk of the body

15

Tinea Barbae

Tinea of the face

16

Tinea Cruris

Tinea inguinally

17

Tinea pedis

Tinea of the foot

18

Normal treatment for tinea?

Topical anti-fungal treatment. When hair or nails are involved, oral antifungal treatment is usually necessary.

19

How do we diagnose Tinea?

Microscopy/culture

20

Subcutaneous Mycoses

Invade the subcutaneous fat. This is rare, usually induced by trauma and often has a slow progression requiring surgery.

21

Spreading pattern of subcutaneous Mycosis

Laterally, not to distant organs

22

Sprotrichosis is caused by what

sporothrix schenckii transmission. This is a dimorphic fungi found in soil and vegetation. Penetrated epidermis will permit growth via a yeast form of this.

23

Symptoms of a sprotrichosis mycosis infection

Usually starts as a small nodule that ulcerates and becomes painful. 2-3 weeks later secondary lesions along lymphatics progress proximally (sporotrichoid spread- other diseases exhibit a similar “spread”).

24

Diagnosis of Sprotrichosis mycosis

Biopsy. Can establish genus and species from culture

25

Treatment of Sprotrichosis Mycosis

Intraconazole orally - can take several weeks

26

How do we typically get Sprotrichosis mycoses?

Inhalation typically

27

Chromomycosis

Found in the tropics, this is an opportunistic fungus

28

What is a granulomatous infection?

Result of an opportunistic subcutaneous fungal infection. They emerge out from the subcutaenous tissue and emerge outward. They form medlar bodies

29

How do we treat subcutaneous mycoses?

Very difficult, usually try azoles long term

30

Eumycotic mycetoma

Caused by a variety of fungi in the soil entering wounds. Causes a deep subcutaneous fungal infection that results in gross localized swelling with underlying sinus tracts. Granulomas can develop with granule formation and pus

31

Fungi that can cause Eumycotic mycetoma

Madurella (most common)
Fusarium
Acremonium
Exophiala
Scedosporium

32

What eumycotic mycetoma do we find in trench warfare?

Madurella

33

How do we diagnose Eumycotic mycetoma

Detection of granules by gross visualization or microscopy

34

How do we treat Eumycotic mycetoma

Antifungal agents and local surgery. Treatment is usually not effective. Frequent cure is amputation

35

Discuss microscopy as it is used to diagnose fungal infections: 10% KOH Tests

10% KOH tests are typically done on skin scraping. If you think cutaneous fungal infection, you may do this. KOH dissolves away keratinocytes and you may see fungal elements

36

Discuss microscopy as it is used to diagnose fungal infections: Calcofluor white

Calcofluor white (generally a go to stain) is a fluorescent dye which binds to fungal walls

37

Discuss microscopy as it is used to diagnose fungal infections: India Ink

o India ink (not as popular) used on CSF to look for Cryptococcus (has a large suger capsule. It shows as a halo under india ink

38

Discuss microscopy as it is used to diagnose fungal infections: Methenamine Silver

There are a number of silver stains. This is fairly popular.

39

Why is culture is considered the gold standard for detecting fungi

1. More sensitive than microscopy
2. Allows for ID via mycelium appearance or presence of asexual spores (genus and species)
3. Usually grown on Sabouraud’s agar – designed to inhibit bacterial growth
4. Most fungi can grow in standard blood culture bottles

40

What is mycology

Study of fungi

41

What type of organism is a fungus?

Fungi are eukaryotic, uni or multicellular, non-photosynthetic, and have chitin and glucan cell walls.

42

What is a good medicinal target structurally on the fungus?

Fungal membrane contains ergosterol (mammal cell walls contain cholesterol so ergosterol is a good medicinal target

43

Different types of general fungi?

They consist of yeasts (unicellular), molds (multicellular), or can be both (dimorphic).

44

Are fungi aerobic or anaerobic?

Aerobic typically

45

How do yeast multiply

Binary Fission
Budding (typically the route they take)

46

What are hyphae and where do we find them?

Molds grow apically and branch via hypae (branches). At the hyphae, molds can grow spores.

47

What are septa and where do we find them?

Hyphae have septa that have pores that allow communication and nutients vs. discrete cells.

48

How do fungal spores reproduce?

Most fungal spores reproduce through mitosis (asexual) although some are sexual and reproduce via meiosis.

49

Can Neutrophils combat fungi? If so how?

Neutrophils fight extracellular molds such as aspergillus and release defensins to fight them