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Flashcards in skin infections 2 Deck (11):
1

Impetigo

(crusted skin): Classic, nonbullous impetigo = impetigo contagiosa = epidemic
impetigo

2

impetigo primarily caused by ??

S. aureus
Streptococcus pyogenes
(GAS) OR BOTH.

3

classic impetigo epi:
age group??
how does it infect??
contagious or not??
what happens in adults??

Peak incidence is in children 2 to 5 years.

Often secondarily infect varicella lesions or lesions present in systemic diseases, such as diabetes mellitus and AIDS and causes scarring.

*Contagious!* Can be passed by fomites. Autoinoculation often causes spread to surrounding areas.

Adults more than children are at increased risk for complications, especially post-streptococcal acute glomerulonephritis (PGN-GAS)

4

impetigo manifestation

In the superficial epidermis, purulent discharge drying on top of the lesion results in a thickened amber/honey colored adhesive crust that resolves in a couple of weeks without scarring.

5

Common Factors Predisposing to Impetigo

Anything that causes scratching
Radiation therapy
Insect bites
Chicken pox
Scabies
Surgery
HSV
Thermal burns
Trauma
Acne

6

epidemic impetigo secondary to ??

shingles: stops along midline
Ramsey-Hunt syndrome

"secondarily impetiginous"

7

impetigo tx

Mupirocin: Impetigo involving limited areas: (topical) Unfortunately, S aureus and MRSA resistance to mupirocin

Retapamulin: New class of topicals/localized impetigo caused by S. pyogenes and MRSA
– Spectrum of retapamulin also includes erythromycin- resistant S. pyogenes, fusidic acid–resistant and mupirocin- resistant S. aureus, and MRSA (including P-VL–positive strains)
• Perform “D-zone test” on all erythromycin-resistant, clindamycin- sensitive strains to identify strains with inducible resistance to clindamycin

8

if impetigo extends deeper??

ecthyma

Deep type of nonbullous impetigo extending into the dermis ("punched out ulcers" with a greenish-yellow crust and violaceous margin, often
suppurative)

9

ecthyma mostly caused by ??
occurs where ??

*More commonly caused by GAS* (so worry about sequelae)
Frequently occurs on legs.
Scarring can occur.

10

ecthyma dx

Gs/Cx to dx Staph from GAS
can also measure anti-teichoic acid Abs

11

another FYI ecthyma

Ecthyma (Pyoderma) gangrenosum
most commonly caused by P. aeurginosa

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