Skin Fungal Infections Flashcards Preview

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Flashcards in Skin Fungal Infections Deck (31)
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1
Q

What are superficial mycoses?

A

Fungi that colonize the keratinized outer layers of the skin, hair and nails

Usually asymptomatic, and only of cosmetic concern

2
Q

What agent causes Pityriasis Versicolor?

A

Malassezia Furfur

Part of normal flora, found in areas of body rich in sebacous glands

3
Q

What are the clinical features of Pityriasis Versicolor?

A

Hyperpigmented or hypopigmented macular lesions that scale readily - chalkybranny appearance

Occurs mot frequently on the upper torso, arms and abdomen

4
Q

How is Pityriasis diagnosed and treated?

A

Direct microscopic examination of KOH treated skin, Wood’s lamp (lesions appear yellow)

Treatment - Selenium disulfide, hyposulfite, thiosulfate or salycylic acid. Ketoconazole 1% in cream

5
Q

What is Tinea Nigra and what agent causes the infection?

A

Superficial fungal infection of the stratum corneum

Hortaea werneckii

6
Q

What is the clinical presentation of Tinea Nigra?

A

Solitary, irregular, pigmented macule usually on the palms or soles

No scaling or invasion of hair follicles

7
Q

How is Tinea Nigra diagnosed and treated?

A

KOH-treated scraping

Azole cream

8
Q

What are cutaneous mycoses and what is the name of the organisms that cause these infections?

A

Infections that extend deeper into the epidermis, as well as invasive hair and nail diseases

Dermatophytes

Also referred to as ringworm or tinea

9
Q

How are dermatophyte infections clinically classified?

A

Location

Tinea Capitis - head

Tinea corporis - smooth or glabrous skin

etc.

10
Q

What is the clinical presentation of Tinea Capitis?

A

Hair becomes grayish, dull and brittle due to ectothrix invasion of hair, hair breaks off near the base

More common in prepubescent children

11
Q

How do tinea infections present generally on the body?

A

Itchy, red, scaling or fissuring of the skin

Ring with irregular borders and a cleared central area may occur

12
Q

What are dermatophytids?

A

Allergic reactions to dermatophyte infections that lead to lesions at different sites from the infection

13
Q

What is the treatment for tinea infections?

A

Azole creams for local

Griseofulvin for early systemic infections

14
Q

What is Wood’s lamp test?

A

Light that uses longwave UV light that makes fungus glow

Detects the presence of a fungal scalp or skin infection

15
Q

What are subcutaneous fungal infections?

A

Infections that involve the deeper layres of the dermis, subcutaneous tissue or bone

Usually associated with some form of trauma (i.e. splinter, thorn, insect bite)

16
Q

What is Sportrichosis?

A

Chronic infection characterized by nodular lesions of the cutaneous or subcutaneous tissues and adjacent lymphatics that suppurate, ulcerate and drain

17
Q

What is the agent of lymphocutaneous sporotrichosis?

A

Sporothrix schenckii

Affects the skin and lymphatic system

Rose gardener’s disease

18
Q

What are the clinical features of lymphocutaneous sporotrichosis?

A

Nodular and ulcerative lesions that develop along lymphatics and drain the primary site of inoculation

No systemic symptoms, despite lymph node involvement

19
Q

How is S. Schenckii diagnosed?

A

KOH stain demonstrates “cigar-shaped” budding

Asteroid bodies - star shaped rays of eosinophilic material

20
Q

What is the treatment for an S. schenckii infection?

A

Potassium iodide

Amphotericin B

21
Q

What is Chromoblastomycosis?

A

Chronic infection of the skin characterized by the development of cauliflower-like lesions

Often seen in workers injured with woods

22
Q

What agent causes Chromoblastomycosis?

A

Fonsecaea pedrosi

Dematiaceous fungi

23
Q

How is chromoblastomycosis diagnosed and treated?

A

Presence of pigmented fungi in tissue sections or pus, sclerotic bodies

Treatment - excision, flucytosine

24
Q

What are medlar bodies?

A

Copper-colored spherical yeast in tissue culture

25
Q

What is Phaeohyphomycosis?

A

Heterogenous group of subcutaneous fungal infections characterized by the presence of darkly-pigemented fungal elements

26
Q

What can phaeohyphomycosis cause?

A

Chronic paranasal sinus

Prosthetic valve endocarditis

Keratomycosis

Widely disseminated infections

27
Q

How is phaeohyphomycosis diagnosed and treated?

A

Periodic acid-Schiff or methenamine silver stain

Treatment: surgical resection, Amphotericin B, Oral ketoconazole and itraconazole

28
Q

What is fungal mycetoma?

A

Clinical syndrome characterized by tumefaction, draining sinuses, and sclerotia.

May progress to maduromycosis

29
Q

What is maduromycosis?

A

Madura foot deforming infection on the foot or hand

30
Q

What is the most common etiological agent of fungal mycetoma?

A

Petriellidium boydii

31
Q

How is fungal mycetoma diagnosed and treated?

A

Macroscopic examination of sclerotia

Difficult to treat, amputation may be necessary