bacteria

Question 1

Front

Answer 1

Back

Question 2

What are pyodermites?

Answer 2

Primary skin infections mainly caused by pyogenic bacteria (Staphylococcus, Streptococcus).

Question 3

Name some resident bacterial flora of skin.

Answer 3

Micrococchi, S. albus, S. epidermidis, Corynebacterium acnes, Pityrosporum ovale, Candida albicans.

Question 4

Name some transient (pathogenic) bacteria.

Answer 4

S. aureus, Streptococcus beta-hemolyticus, Pseudomonas aeruginosa.

Question 5

How does resident flora protect skin?

Answer 5

Hydrolyzes lipids producing free fatty acids toxic to many bacteria.

Question 6

List local factors favoring skin infections.

Answer 6

Alteration of hydrolipidic layer, stratum corneum reduction, maceration, topical therapies (corticosteroids, antibiotics).

Question 7

What is bacterial superinfection?

Answer 7

Infection on previous lesions (dermatitis, wounds, trauma).

Question 8

Most frequent bacteria in skin infections?

Answer 8

Gram+ Staphylococcus aureus, Streptococcus beta-hemolyticus group A.

Question 9

Other bacteria involved in skin infections?

Answer 9

Pseudomonas aeruginosa, Escherichia coli, Enterobacter spp.

Question 10

Diseases caused by Streptococcus pyogenes?

Answer 10

Impetigo vulgaris, erysipelas, cellulitis, scarlet fever.

Question 11

Post-streptococcal complications?

Answer 11

Acute rheumatic fever, acute glomerulonephritis.

Question 12

Diseases caused by Staphylococcus aureus?

Answer 12

Bullous impetigo, SSSS, folliculitis, abscess.

Question 13

What are superficial non-adnexal forms of pyodermitis?

Answer 13

Impetigo, SSSS, scarlet fever, ecthyma.

Question 14

Profound non-adnexal forms?

Answer 14

Erysipelas, infective cellulitis, necrotizing fasciitis, gas gangrene.

Question 15

Adnexal forms?

Answer 15

Superficial and profound folliculitis, abscess, felon (whitlow).

Question 16

Morphology of impetigo vulgaris?

Answer 16

Thin-walled pustule, ruptures to form honey-colored crust (meliceric).

Question 17

Main cause of impetigo vulgaris?

Answer 17

Streptococcus (70% of cases).

Question 18

Morphology of bullous impetigo?

Answer 18

Erythematous maculae progressing to superficial blisters and crusts.

Question 19

Cause of bullous impetigo?

Answer 19

Staphylococcus aureus producing exfoliative toxins ETA, ETB.

Question 20

What is Staphylococcal scalded skin syndrome (SSSS)?

Answer 20

Pediatric emergency with erythema, bullous lesions, epidermal detachment.

Question 21

SSSS typical patient?

Answer 21

Infants, children; rarely immunosuppressed adults.

Question 22

Systemic symptoms of SSSS?

Answer 22

Fever, malaise, crusting around mouth, nose, eyelids.

Question 23

Pathogenesis of SSSS toxins?

Answer 23

ETA and ETB split desmoglein-1 in granular epidermis.

Question 24

What causes scarlet fever?

Answer 24

Streptococcus pyogenes releasing pyrogenic toxin.

Question 25

Symptoms of scarlet fever?

Answer 25

Strawberry tongue, erythematous rash sparing palms/soles, Pastia's lines.

Question 26

Complication of scarlet fever?

Answer 26

Glomerulonephritis.

Question 27

Morphology of ecthyma?

Answer 27

Erythematous plaque, vesiculopustule ruptures into ulcer with adherent crust.

Question 28

Ecthyma common location?

Answer 28

Feet, legs, thighs, buttocks.

Question 29

Risk factors for ecthyma?

Answer 29

Poor hygiene, malnutrition, immunodeficiency.

Question 30

Superficial folliculitis cause?

Answer 30

Staphylococcus aureus, Pseudomonas aeruginosa.

Question 31

Superficial folliculitis presentation?

Answer 31

Follicular pustules with erythematous halo.

Question 32

Profound folliculitis (sycosis) cause?

Answer 32

Staphylococcus aureus.

Question 33

Sycosis common in?

Answer 33

Males 20-40 years, beard areas.

Question 34

Sycosis presentation?

Answer 34

Inflammatory plaques with yellow crusts, split ripe fig appearance.

Question 35

What is a skin abscess?

Answer 35

Localized pus collection, often painful, warm, and swollen.

Question 36

Common sites for abscess?

Answer 36

Axilla, groin, rectum, vaginal area, tailbone.

Question 37

Evolution of abscess?

Answer 37

Nodule ulcerates, requires surgical drainage if deep.

Question 38

What is felon (whitlow)?

Answer 38

Painful abscess on fingertip (palmar aspect).

Question 39

What is erysipelas?

Answer 39

Acute febrile dermo-hypodermitis caused by Streptococcus group A.

Question 40

Erysipelas morphology?

Answer 40

Erythematous, hot indurated plaque with sharply demarcated raised border.

Question 41

Common sites of erysipelas?

Answer 41

Face (butterfly shape), legs.

Question 42

Necrotizing fasciitis cause?

Answer 42

Beta-hemolytic streptococcus + anaerobes (Bacteroides).

Question 43

Necrotizing fasciitis presentation?

Answer 43

Necrosis, ulcers with ill-defined borders, sepsis.

Question 44

Necrotizing fasciitis treatment?

Answer 44

Surgical debridement + systemic antibiotics.

Question 45

What is Fournier gangrene?

Answer 45

Necrotizing fasciitis localized to genitalia.

Question 46

What is gas gangrene?

Answer 46

Clostridium perfringens infection causing muscle and skin necrosis.

Question 47

Gas gangrene symptoms?

Answer 47

Fetid odor, gas crackling, severe pain.

Question 48

What is erythrasma?

Answer 48

Corynebacterium minutissimum infection of skin folds.

Question 49

Erythrasma morphology?

Answer 49

Brown scaly patches without vesicles or erosions.

Question 50

What is pseudomonas intertrigo?

Answer 50

Greenish lesions with fruity odor, in moist areas.

Question 51

Cause of green nail disease?

Answer 51

Pseudomonas aeruginosa in moist environments, artificial nails.

Question 52

What is cat scratch disease?

Answer 52

Bartonella henselae infection, papules, regional lymphadenopathy.

Question 53

What is Lyme disease?

Answer 53

Borrelia burgdorferi (tick-borne); erythema migrans, lymphocytoma, arthritis.

Question 54

What is plague?

Answer 54

Yersinia pestis infection transmitted by fleas (Xenopsylla cheopis).