SM 263: Bacterial and Fungal Skin Infections

Question 1

What are Dermatophytoses?

Answer 1

Fungal infections of the skin

Question 2

What are the 3 groups of cutaneous fungi that cause superficial infections?

Answer 2

Dermatophytes, Malassezia spp, Candida spp.

Question 3

What tissue do Dermatophytes infect?

Answer 3

Keratinized tissues such as the stratum corneum, the nail, and the hair

Question 4

What does the term Tinea refer to?

Answer 4

Dermatophytoses, specific to the site of location: tinea pedis = foot

Question 5

What is Tinea capitis?

Answer 5

A dermatophytosis of the scalp and hair spread by contact with humans and fomites

Question 6

Can inanimate objects like hair brushes spread Tinea capitis?

Answer 6

Yes, because it spreads by fomites

Question 7

Is Tinea capitis inflammatory on noninflammatory?

Answer 7

Both; Kerion is inflammatory

Question 8

What is a Kerion?

Answer 8

A painful, inflammatory boggy mass with broken hair follices due to Tinea capitis that can scar

Question 9

Which topical agent can treat Tinea capitis?

Answer 9

None - need to use a systemic agent

Question 10

What can treat Tinea capitis?

Answer 10

A systemic drub like Griseofulvin or Terbafine granules

Question 11

What shows up as branched septated hypae on KOH?

Answer 11

Tinea pedis

Question 12

What is athletes foot?

Answer 12

Tinea pedis

Question 13

How does Tinea pedis present?

Answer 13

Fine scales on the sole of the foot and between toes with vesicles on the bottom/side of the foot

Question 14

What is the interdigital type of Tinea pedis?

Answer 14

The most common type of Tinea pedis, presents with scaling and redness between the toes

Question 15

What is the mocassin type of Tinea pedis?

Answer 15

A form of Tinea pedis with sharply marginated scale alongside the lateral borders of the feet, heels, and shoes

Looks like a lowcut sock

Question 16

What is the vesiculobullous type of Tinea pedis?

Answer 16

A type of Tinea pedis that looks like a bulge on the foot - essentially, it’s not in between toes or on the entire foot

Question 17

What is Onchomycosis?

Answer 17

A fungal infection of the nailbed, which may arise from Tinea pedis infection

Question 18

How is Onchomycosis treated?

Answer 18

Can’t use topical antifungals; need to prove it’s a fungal infection and treat with expensive oral meds

Question 19

How does Tinea corporis present?

Answer 19

An annular lesion with a central clearing

Question 20

Where does Tinea corporis infect?

Answer 20

Infects the body generally

Question 21

What shows up as short hyphae and small round spores in a “spaghetti and meatball” pattern on KOH exam?

Answer 21

Tinea Versicolor

Question 22

What causes Tinea versicolor?

Answer 22

Not a fungi/dermatophytosis; due to overgrowth of Malassezia, a yeast

Question 23

How does Tinea versicolor present?

Answer 23

Variable colored often round patches in the trunk, with no visible scale but scale that may be evoked when rubbed with a finger

Question 24

What is the diagnostic feature of Tinea versicolor?

Answer 24

A scale that only appears after being rubbed

Question 25

How is Tinea versicolor treated?

Answer 25

Selenium sulfide shampoo + topical antifungals Oral antifungals when it recurrs

Question 26

What is Diaper Candidiasis?

Answer 26

Satellite papules and pustules in the diaper area that does not respond to barrier creams like Zinc Oxide

Question 27

What causes Diaper Candidiasis?

Answer 27

Urease enzymes in feces liberate amonia from Urine in dirty diapers that are not changed, disrupting the epidermal barrier and allowing for Candida colonization and the rash

Question 28

What causes Cutaneous candidiasis?

Answer 28

C. albicans

Question 29

Where is C. albicans normally found?

Answer 29

Normal flora in mucous membranes

Question 30

What is the treatment for Cutaneous candidiasis?

Answer 30

Topical antifungals

Question 31

What is Candidal Intertrigo?

Answer 31

Candidiasis of large skin folds associated with obesity and diabetus

Question 32

What is seen on KOH exam of Candidal Intertrigo?

Answer 32

Psuedohyphae

Question 33

How is Candidal Intertrio treated?

Answer 33

Topical antifungals

Question 34

What is thrush?

Answer 34

Mucocutaneous candidiasis

Question 35

What is Sporotrichosis?

Answer 35

A subcutaneous infection caused by Sporothrix Schenickii fungi that causes a chain of dermal nodules along a lymph course

Question 36

Where is Sporotrichosis acquired?

Answer 36

Sporothrix grows in decaying vegetable matter

Question 37

If you see broad based buds, think...?

Answer 37

Blastomycosis

Question 38

Where does Blastomycosis infect?

Answer 38

Commonly infects lungs and disseminates to skin of face/extremities

Question 39

What are superficial pyodermas?

Answer 39

Infections in the epidermis

Question 40

Which layer of skin does Impetigo infect?

Answer 40

Below the Stratum Corneum

Question 41

Where does Folliculitis effect?

Answer 41

The hair

Question 42

What is Bullous Impetigo?

Answer 42

A bacterial infection caused by S. aureus exotoxin

Question 43

How does the S. aureus exotoxin cause Bullous Impetigo?

Answer 43

Exotoxin binds Desmoglein-1 in children

Question 44

What can the S. aureus exotoxin cause?

Answer 44

Bullous impetigo in localized areas or Scalded Skin Syndrome if generalized

Question 45

What does Non-bullous Impetigo look like?

Answer 45

Honey-colored crust

Question 46

What is Staphylococcal Scalded Skin Syndrome?

Answer 46

A DEEP skin infection that results from S. aureus exotoxin in the blood leading to superficial skin peeling

Question 47

What do wound cultures in Scalded Skin Syndrome grow?

Answer 47

Nothing at all

Question 48

Who gets Scalded Skin Syndrome?

Answer 48

Kids < 5 y/o and adults with renal disease

Question 49

How is Scalded Skin Syndrome treated?

Answer 49

Antibiotics + fluids + supportive care

Question 50

What is Scarlet Fever?

Answer 50

An exotoxin-triggered reaction with cutaneous manifestations that is a delayed type skin reactivity to strep products

Question 51

Is Scarlet Fever an infection and what causes it?

Answer 51

Not a skin infection; caused by Group A Strep SPE-A,B,C Exotoxins

Question 52

How does Scarlet Fever present?

Answer 52

Abrupt pharyngitis and fever with rash in 24/48 hours, followed by white and then red strawberry tongue

Question 53

How does the skin change in Scarlet FEver?

Answer 53

Head and neck first effected with diffuse sandpaper erythema with circumoral pallor, which later spreads to the whole body

Question 54

What are Pastia's line?

Answer 54

Linear petechia in the skin folds during Scarlet Fever

Question 55

How is Scarlet Fever treated?

Answer 55

Penicillin

Question 56

What is Cellulitis?

Answer 56

An infection of the Dermis that presents as a spreading erythematous, tender plaque often in the lower leg

Question 57

Where is Cellulitis found and what does it look like?

Answer 57

Lower leg; looks like a spreading, erythematous tender plaque

Question 58

What causes Cellulitis?

Answer 58

Gram positives like Group A Strep or S.. Aureus Also bite bugs like Pasteurella and Eikenella

Question 59

How should Cellulitis be treated?

Answer 59

Antibiotics with gram positive coverage, and treat Tinea pedis if present (Pedis may cause an entry point for bacteria)

Question 60

What is Erysipelas?

Answer 60

A superficial cellulitis of the face and lower extremities that presents with superficial edema and erythema in a sharply-defined border

Question 61

What causes Erysipelas?

Answer 61

Group A Strep

Question 62

How does an Abscess present?

Answer 62

Erythematous, warm, and painful/tender to palpation; pustule surrounded by erythematous edema

Question 63

How is an Abscess treated?

Answer 63

Incision and Draininge + wound culutres + antibiotics

Question 64

What is Folliculitis?

Answer 64

Small papules and pustules on an erythematous base pierced by a central hair Due to S. aureus

Question 65

What causes Folliculitis?

Answer 65

S. aureus

Question 66

How is Folliculits treated?

Answer 66

Clean with soap and water, add anti-staphyloccocal agents

Question 67

What causes Furuncles and Carbuncles?

Answer 67

S. aureus

Question 68

What causes Anthrax?

Answer 68

Bacillus Anthracis, endemic to wild and domestic animals

Question 69

What does Bacillus Anthracis look like on slides?

Answer 69

Large, box-car shaped gram-positive

Question 70

What does cutaneous Anthrax look like?

Answer 70

A black eschar

Question 71

What is "Lues"?

Answer 71

Syphillis

Question 72

What causes Syphillis?

Answer 72

Treponema Pallidum

Question 73

How does Syphillis present?

Answer 73

On the palms and soles, but could look like a lot of things

Question 74

What is the test for Syphillis?

Answer 74

RPR with Prozone

Question 75

What is the treatment for Syphillis?

Answer 75

Penicillin

Question 76

How might TB effect the skin?

Answer 76

Lupus Vulgaris and Scrofulderma

Question 77

What causes fish tank granulomas?

Answer 77

M. marinum

Question 78

What causes chronic granulations of the skin?

Answer 78

M. leprae