ID Derm Part 2

Question 1

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

Answer 1

Dermatophytes

Malassezia Spp.

Candida Spp.

**superficial cutaneous and limited to the epidermis

Question 2

What tissues do dermatophytes infect?

Answer 2

keratinized tissues

stratum corneum

nail or hair

Question 3

tinea capitis

Answer 3

dermatophytosis of the scalp and associated hair

most cases caused by Trichophyton tonsurans

most common worldwide is Microsporum canis

multiple patchy alopecic areas of different sizes and shapes - hair shafts are broken off near scal surface

Question 4

kerion

Answer 4

painful inflammatory booggy mass with broken hair follicles

may discharge pus

higher risk of carring

Question 5

treatment for tinea capitis

Answer 5

systemic treatment

griseofulvin

terbinafine

Question 6

tinea pedis (athlete’s foot)

Answer 6

may have fine scales on the soles and between toes

vesicles often appear on bottom/sides of foot

interdigital caling and scaling on the bottom of the feet

interdigital type, moaccasin type, and vesiculobullous type

Question 7

onychomycosis

Answer 7

potential complication of tinea pedis

chronic fungal infection of the nailbed

responds poorly to topical antifungals

Question 8

tinea corporis

Answer 8

aka “ringworm”

annular lesions with central clearing is typical

centrifugal spread after 1-3 week incubation period

caused by:

• T. rubrum
• M. canis
• T. mentagrophytes

Question 9

tinea facei

Answer 9

facial involvement excluding beard and musctache areas

scaling present in fewer than 2/3 of cases

Question 10

tinea versicolor

Answer 10

not a dermatophytosis

caused by overgrowth of species of Malassezia

tends to recur annually in the summer months

characterized by variable colored often round patches, most commonly in the trunk

Question 11

treatment of versicolor

Answer 11

2.5 selenium sulfide shampoo

topical antifungals dialy for 2 weeks

oral antifungals for recalcitrant disease

Question 12

diaper candidiasis

Answer 12

satellite papules and pustules help differentiate this from other eruptions

rash does not improve with application of barrier creams

urease enzymes present in feces release ammonia from urine, which cause acute irritant effect and disrupt epidermal barrier

Question 13

cutaneous candidiasis

Answer 13

C. albicans most common

part of normal flora of mucous membranes

treat with topical antifungals

Question 14

candidal intertrigo

Answer 14

candidiasis of large skin folds

may arise in groin, armpits, between buttocks, under large pendulous breasts and overhanging abdominal folds

Question 15

sporotrichosis

Answer 15

sporothrix schenickii

subcutaneous infection by fungus

grows in decaying vegetable matter

dermal nodule appears then a chain of secondary nodules on the course of the lymphatics

Question 16

blastomycosis

Answer 16

chronic mycosis, most cases in Great Lakes region in US

skin lesions are common from dissemination in face and extremities

thick walled refractile spheres with broad based buds

Question 17

superficial pyodermas

Answer 17

infections in the epidermis, just below the stratum corneum (impetigo) or the hair follicles (folliculitis)

S. aureus is the most common

Group B strep is a common cause in babies

Question 18

bullous impetigo

Answer 18

bacterial infection caused by S. aureus

caused by secreted exotoxin - exfoliative toxins that cause blistering by binding to desmoglein-1

Question 19

staphylococcal scalded skin syndrome

Answer 19

focus of infection secretes toxin into the blood

leads to widespread superfiical blisters

wound cultures from erosions are negative

Question 20

What exotoxins cause staph scalded skin syndrome?

Answer 20

epidermolytic/exfoliative toxins A and B

bind to desmoglein-1

Question 21

scarlet fever

Answer 21

caused by S. pyogenes

exotoxins SPE-A, B, C

produced by group A strep

delayed-type skin reactivity to strep products

beefy-red pharynx, tonsillitis, submandibular LAD

white strawberry tongue in first several days and red-strawberry tongue after 4-5 days

sandpaper erythema and circumoral pallor

pastia’s lines - linear petechia in antecubital axillary folds

Question 22

cellulitis

Answer 22

infection of dermis that often begins with a wound or fungal infection

erythematous, tender plaque

more common in lower leg

80% caused by group A strep and S. aureus or ther infections

Question 23

therapy for cellulitis

Answer 23

begin antibiotics immediately with coverage for gram positive bacteria

Question 24

erysipelas

Answer 24

superficial cellulitis with marked dermal lymphatic involvement

main pathogen is group A strep

Question 25

abscess

Answer 25

collection of pus within the dermis and deeper skin tissue

painful, tender, fluctuant, and erythematous nodules

treat with incision and drainage, wound culture

Question 26

folliculitis

Answer 26

S. aureus most common

multiple small papules and pustules on erythematous base

Question 27

management of folliculitis

Answer 27

cleanse with antibacterial soap and water 3x/day

oral or topical antibiotics

Question 28

furunculosis

Answer 28

a furuncle is an acute, round, tnder, circumscribed, perifollicular abscess that generally ends in central suppuration

Question 29

carbunculosis

Answer 29

a carbuncle is a coalescence of several inflamed follicles into a single inflammatory mass with purulent drainage from multiple follicles

Question 30

What causes furuncles and carbuncles?

Answer 30

S. aureus

treat with oral antibiotics

Question 31

clinical manifestations of anthrax

Answer 31

inhalational, gastrointestinal, cutaneous

Question 32

secondary syphilis

Answer 32

trepnema pallidum

lymphadenopathy and clasically palms and soles

can look like many other diseases

lesions contain spirochetes

Question 33

testing for syphilis

Answer 33

RPR with prozone

proxone phenomenon: antigen/antibody mismatch such that when there is so much exces antibody, it clumps, leading ot false negative

Question 34

syphilis treatment

Answer 34

IM penicillin

Question 35

What are the two classic presentations of TB?

Answer 35

lupus vulgaris and scrofuloderma

Question 36

M. marinum infection

Answer 36

fishtank granulomas

Question 37

leprosy

Answer 37

chornic granulomatous infection, especially of skin and nerves