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49 Cards in this Set
- Front
- Back
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Impetigo is a (superficial/deep/subcutaneous) infection).
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Superficial
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What are 3 predisposing factors for pyodermal infections?
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Pre-existing trauma to skin
Pre-existing skin dz Impaired host immunity |
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Most pyodermal skin infections are caused by non-resident flora such as what?
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Staph aureus and strep pyogenes
S. aureus is MOST COMMON in U.S. |
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What is the most common pathogen in Impetigo?
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Staph aureus
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What is the most common bacterial skin infection in children?
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Impetigo
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Although s. aureus is not a resident flora of the skin, where might it be found?
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"Transient" flora of nasopharynx, tends to colonize in anterior nares
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What highly contagious skin infection (primarily in children and young adults) is more common in hot, humid weather, especially at sites of minor trauma (ie insect bites and scratches)?
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Impetigo
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Bullous impetigo is most common in what age group?
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Neonates
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What are the clinical features of bullous impetigo?
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-begins as small vesicles, forms flaccid bullae, rupture and are shiny
-NO thick crust formation -common on face |
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Why do blisters form in bullous impetigo?
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because of exfoliative toxins (A-D) of s. aureus
Considered a "localized" form of staph scalded skin syndrome |
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What are the clinical features of Non-bullous impetigo?
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-begin as thin-walled vesicles on erythematous base, then rupture readily
-forms yellow "honey-colored" crust -can have glistening red or pink oozing surface -commonly on face -benign, self-limited, tends to resolve w/i 2 wks |
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What is a rare complication of non-bullous impetigo caused by strep pyogenes?
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Acute poststreptococcal glomerulonephritis
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What is the treatment for Impetigo (w/o systemic symptoms)?
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Mupirocin 2% ointment
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What infection is considered an "ulcerated" form of non-bullous impetigo?
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Ecthyma
It's a deeper infection, extending into the dermis |
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What are the causative organisms of ecthyma?
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s. aureus and/or s. pyogenes
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What are the clinical features of Ecthyma?
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-begins as vesicle or vesiculopustule, ruptures to form thick circular crust*
-infection underneath penetrates dermis to create ulceration -if you remove crust, lesion is said to have circular "punched-out" appearance d/t ulceration* -commonly on lower extremities* |
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What age group is commonly a/w Staphylococcal Scalded Skin Syndrome?
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Primarily children under 6*
Rare in adults, but also more fatal in adults (>50%) |
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What are the clinical features of Staphylococcal Scalded Skin Syndrome?
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-kid looks irritable!*
-malaise -erythema on head -> extends to body -> superficial flaccid bullae* -> rupture, leave moist, erythematous base, "scalded" appearance* -> scaling and desquamation* -> heals w/o scarring |
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What causes the blister formation in Staph Scalded Skin Syndrome?
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Exfoliative toxins A and B of s. aureus
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How do you treat Staph Scalded Skin Syndrome (extensive, generalized form)?
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Hospitalization and parenteral IV antibiotics
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What is the most common pathogen in Erysipelas?
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Strep pyogenes
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What are the clinical features of Erysipelas?
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-Systemic symptoms - clear margin of demarcation from normal skin*
-abrupt onset of fever, chills, malaise, nausea -most commonly on face/LE* (LE>face now) -small plaque of erythema, progressively spreads, clear demarcation w/ slightly elevated border* important clues: -hot, tense, indurated (firm)* -painful to palpation* |
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What layers do Erysipelas and Cellulitis affect?
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Erysipelas - dermis, also spreads to regional lymph
Cellulitis - deep dermis and subcutaneous tissue; also can spread to regional lymph |
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What are the most common pathogens in Cellulitis?
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Staph aureus and strep pyogenes
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What are the clinical features of Cellulitis?
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-often preceded by fevers, chills, malaise
-ill-defined, non-palpable border!* -warmth, pain to palpation, edema -most common on head/neck in children; extremities (mostly legs) in adults |
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What is the treatment for mild cases of cellulitis?
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10 days of oral antibiotic with good Gram+ coverage
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What is the treatment for cellulitis in patients who are seriously ill or who have facial cellulitis?
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Hospitalization and parenteral antibiotics
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Folliculitis is an infection of what?
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The hair follicle.. duh.*
Can be superficial or deep |
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What is the most common pathogen of folliculitis?
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Staph aureus
*Pseudomonas folliculitis is also a concern d/t whirlpools and hot tubs |
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What type of skin infection occurs in bearded men from shaving?
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Sycosis Barbae* (beard area folliculitis)
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A patient presents on a Monday w/ multiple red papules (or pustules...) in a bikini distribution. They had some friends over in the hot tub on Saturday night.
a) What do they probably have? b) How do you know? c) What do you do for them? |
a) Hot tub folliculitis d/t pseudomonas aeruginosa
b) hot tub hx, under bathing suit, monomorphic lesions c) It is self-limited (7-10 days), so antibiotics not necessary. Tell them to clean and purify the water!* They can add bromide to the water. |
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a) Pseudofolliculitis barbae is most common in what demographic?
b) How do you treat it? |
a) Black men*
b) benzoyl peroxide + clindamycin BID 2-10 weeks "ingrown hairs" create a FB reaction |
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What do abscesses and furuncles have in common?
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Both are nodular, "walled-off" collections of pus*
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What is the main difference between abscesses and furuncles?
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Abscesses can occur anywhere on the body! Whereas furuncles must involve a hair follicle
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What is the term for a contiguous collection of infected follicles (collection of furuncles)?
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Carbuncle*
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What is the most common pathogen in furuncles?
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Staph aureus
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What are the clinical features of a furuncle?*
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-usually begin as hard, tender, red nodules
-tend to enlarge, become fluctuant and painful -may have pustular center |
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What are the clinical features of a carbuncle?
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-extend deeper into subcutaneous tissue
-surface usually has multiple draining sinus tracts -systemic symptoms common -slow to heal, always scar |
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Most simple furuncles respond well to what treatment?
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Warm compresses that promote maturation, drainage, and resolution of symptoms*
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What is the treatment for fluctuant lesions?
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Incision and drainage
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What 4 instances (in furuncles/abscesses/carbuncles) are systemic antibiotics recommended?*
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1. furuncles around nose, in nares, or in external auditory canal
2. large and recurrent lesions 3. lesions w/ surrounding cellulitis 4. lesions not responding to local care |
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T/F
MRSA infections are only hospital-acquired. |
False!
Not anymore. It is a growing problem in communities, even in young, healthy individuals |
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MRSA has acquired what gene that led to its resistance?
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mecA gene, which encodes Penicillin-Binding Protein 2A (PBP2A), which has a low affinity for beta-lactams like methicillin.
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What genotypes are a/w:
a) HA-MRSA b) CA-MRSA |
a) SCCmec types I, II, III
b) SCCmec type IV |
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What are some risk factors for MRSA?*
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•Prior antibiotic use
•Day care attendance •Healthcare visits •Hospitalization •IV drug abuse •Invasive indwelling devices •Long-term care facility residency •Long-term hemodialysis •Surgical procedures •Underlying chronic illness •Immunosuppression •Athletics – fencing, football, rugby, volleyball, wrestling, weight lifting •Sometimes no apparent risk factor |
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What are the most common skin manifestations of MRSA?*
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Abscess, abscess+cellulitis, cellulitis
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How do you diagnose MRSA?
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Culture!
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With recurrent MRSA infections, it is important to...
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Find the source*
likely colonized in anterior nares, axillae, perineum, feet - can lead to re-infections, so treat areas w/ topical mupirocin |
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What is the treatment for MRSA skin infections?
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Incision & drainage*
Oral antibiotics* Topical Mupirocin* |
