SM_263a: Bacterial and Fungal Skin Infections Flashcards Preview

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Flashcards in SM_263a: Bacterial and Fungal Skin Infections Deck (47)
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1

Superficial cutaneous fungal infections are limited to the ____ and are caused by ____, ____, and ____

Superficial cutaneous fungal infections are limited to the epidermis and are caused by dermatophytes, Malassezia spp., and Candida spp.

 

 

(dermatophytes include Trichophyton spp., Microsporum spp., and Epidermophyton spp. and infect keratinzed tissues - stratum corneum, nail, hair)

2

Arthrospores inside hair shafts (endothrix) on KOH stain are indicative of ____

Arthrospores inside hair shafts (endothrix) on KOH stain are indicative of tinea capitis

3

Tinea capitis is spread through ____

Tinea capitis is spread through direct contact with animals, humans, and fomites

4

Describe tinea capitis variants

Tinea capitis variants

  • Non-inflammatory: seborrheic, black dot
  • Inflammatory: kerion (painful inflammatory boggy mass w/ broken hair follicles, risk of scarring)

5

Tinea capitis is treated ____

Tinea capitis is treated systemically (griseofulvin, terbenafine)

 

(topical agents are ineffective)

6

Branched septate hyphae on KOH stain are indicative of ____

Branched septate hyphae on KOH stain are indicative of tinea corporis

 

(parallel throughout entire length)

7

Tinea pedis is known as ____

Tinea pedis is known as athlete's foot

 

  • May have fine scales on sole and between toes, vesicles often appear on bottom / sides of foot
  • Interdigital type: most common, presents with scaling and redness between toes and may have associated maceration
  • Mocassin type: sharply marginated scale, distributed along lateral borders of feet, heels, and soles
  • Vesicobullous type

8

____ is a potential complication of tinea pedis and involves ____

Onychomycosis is a potential complication of tinea pedis and involves chronic fungal infection of nailbed

9

Onychomycosis should be ____ then ____ and responds poorly to ____

Onychomycosis should be proved then treated and responds poorly to topical antifungals

 

 

(identification of fungus in affected nail via positive KOH prep or nail biopsy is necessary before treatment)

10

This is ____

This is tinea corporis

 

(annular lesion w/ central clearing, caused by T. rubrum / M. canis / T. mentagrophytes)

11

Tinea corporis is also known as ____ and refers to ____

Tinea corporis is also known as ringworm and refers to dermatophytosis of the skin of the body

 

 

(itchy, the margin of lesion is most active / central area tends to heal, scraping should be taken from red scaly margin for KOH exam)

12

This is ____

This is tinea versicolor

13

Tinea versicolor is ____ pattern on KOH prep

Tinea versicolor is spaghetti and meatball pattern in KOH prep

14

Describe tinea versicolor

Tinea versicolor

  • Not a dermatophytosis
  • Caused by overgrowth of Malassezia: lipophilic yeast that is a normal resident in keratin of the skin and hair follicles
  • Tends to recur annually in the summer months
  • Characterized by variable colored, often rounded, patches - most common trunk
  • Visible scale often not present but seen when rubbed with finger or scalpel blade

15

Visible scale not present but scale readily seen when rubbed with finger / blade refers to ____

Visible scale not present but scale readily seen when rubbed with finger / blade refers to tinea versicolor

16

Describe tinea versicolor treatment

Tinea versicolor

  • 2.5% selenium sulfide shampoo
  • Topical antifungals daily for 2 weeks
  • Oral antifungals for recalcitrant disease
  • Relapse / recurrence is the rule

17

This is ____

This is diaper candidiasis

 

(beefy red plaques with very fine white scale in groin area, skin creases involves, satellite papules and pustules noted on inner thigh and abdomen)

18

Diaper candidiasis is characterized by ____ and does not improve with ____

Diaper candidiasis is characterized by satellitle papules and pustules and does not improve with application of barrier creams

 

(irritant diaper dermatitis is erythema, erosion, spares skin folds, severe cases may show ulcerated papules and islands of re-epithelialization)

19

Describe pathogenesis of diaper candidiiasis

Diaper candidiasis pathogenesis

  1. Urease enzymes present in feces release ammonia from urine
  2. Acute irritant effect
  3. Disruption of epidermal barrier
  4. Entry of Candida (present in feces)

 

(wet and dirty diapers that are not changed on a regular basis contribute to development of diaper dermatitis)

20

Cutaneous candidiasis is most often caused by ____ and treated with ____

Cutaneous candidiasis is most often caused by Candida albicans and treated with topical antifungals

 

(Candida albicans is part of normal flora of mucous membranes of upper respiratory, GI, and female genital tracts)

21

Candidal intertrigo affects ____, commonly affects ____ patients, manifests as ____ on KOH exam, and is treated with ____

Candidal intertrigo affects large skin folds, commonly affects obese patients, manifests as pseudohyphae, and is treated with antifungal agents

 

(prevention is keep intertriginous areas dry / cool / clean and encouraging weight loss for obese patients)

22

Sporotrichosis is ____ infection caused by ____ growing on ____ and manifests as a ____ 

Sporotrichosis is a subcutaenous infection caused by Sporothrix Schenickii growing on decaying vegetable matter and manifests as a dermal nodule then chain of secondary nodules on the course of lymphatics

23

Broad based budding yeast is ___ and can manifest on skin as a result of ____

Broad based budding yeast is blastomycosis and can manifest on skin as a result of dissemination from lungs

 

(Great Lakes region in the US, thick-walled rounded refractile spheres)

24

Superficial pyodermas are ____

Superficial pyodermas are infections in the epidermis just below the stratum corneum (impetigo) or in hair follicles (folliculitis)

 

  • Staphylococcus aureus is most common cause in industrialized nations
  • Group B strep is common cause in babies

25

Bullous impetigo is a bacterial infection caused by ____ and results from a ____

Bullous impetigo is a bacterial infection caused by Gram positive bacteria (Staphylococcus aureus) and results from a secreted exotoxin

 

(disrupts desmogleins in desmosomes -> causes blisters)

26

Staphylococcal scalded skin syndrome is ____

Staphylococcal scalded skin syndrome is when a focus of infection secretes toxin that bind to desmoglein-1 in the granular cell layer into the blood, leading to widespread blisters

 

(not a skin infection)

27

Staphylococcal scalded skin syndrome is caused by ____ that bind to ____ in the ____ cell layer and produce ____

Staphylococcal scalded skin syndrome is caused by 2 endotoxins that bind to desmoglein-1 in the granular cell layer and produce blistering

28

____ and ____ are at risk for staphylococcal scalded skin syndrome

Kids < 5 years and adults with renal disease are at risk for staphylococcal scalded skin syndrome

 

 

29

Wound cultures from erosions are ____ in staphylococcal scalded skin syndrome

Wound cultures from erosions are negative in staphylococcal scalded skin syndrome

30

Scarlet fever is a ____ caused by ____

Scarlet fever is an exotoxin-triggered reaction with cutaneous manifestations caused by Group A Streptococcal pyrogenic exotoxins

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