skin and soft tissue infection Flashcards
things to consider
organism
host: diabetes, immunosuppression, predisposing factors e.g. atopic dermatitis
site:
environment: drug resistant strains, drug allergies
impetigo
superficial skin infection
highly infectious
kids 2-5yrs
impetigo organisms
staph aureus mostly
strep pyogenes
impetigo features
multiple vesicular lesions on erythematous base
golden crust
usually exposed parts of body: face, extremeties
impetigo predisposing factors
skin abrasions poor hygiene atopic dermatitis insect bites chicken pox minor trauma burns
erysipelas
infection of upper dermis
most commonly strep pyogenes
erysipelas features
painful, red areas
distinct elevated borders
assoc fever
regional lymphadenopathy + lymphangitis
erysipelas risk factors
pre-existing lymphodema venous stasis obesity paraparesis DM
cellulitis
diffuse skin infection involving dermis and epidermis
staph a and strep pyogenes
possible source bacteraemia
cellulitis features
spreading erythematous area with no distinct borders
fever
regional lymphadenopathy and lymphangitis
cellulitis predisposing factors
DM
lymphadema
tinea pedis
cellulitis and erysipelas Mx
combination anti-staph and anti-strep antibiotic
extensive disease: admission for IV antib and rest
hair assoc infections
Folliculitis
Furunculosis
Carbuncles
folliculitis
circumscribed pustular infection of hair follicle
up to 5mm diameter
staph aureus
folliculitis presentation
small red papules
central area of purulence may rupture and drain
typically found head, back, buttocks
folliculitis Rx
none
topical antibiotics
furuncolosis
single hair follicle-associated inflammatory nodules
boils
staph aureus
furunculosis features
extends into dermis and subcut tissue
may drain purulent material
usually affects moist, hairy, friction prone areas: face, axilla, buttocks
furunculosis Rx
none
topical antib
oral antib
furunculosis risk factors
DM atopic dermatitis obesity kidney disease corticosteroid use
carbuncle
infections extends to involve multiple furuncles
multi-sepatated abscess
carbuncle features
purulent material multiple sites
fever
multi-septated abscess
often back, neck
carbuncle Rx
hospital
surgery
IV antib
necrotising fasciitis predisposing factors
DM surgery trauma peripheral vascular disease skin popping
necrotising fasciitis T1
mixed aerobic and anaerobic infection
diabetic foot infection, Fournier’s gangrene
strep staph enterococci gram = bacilli clostridium
necrotising fasciitis T2
mono-microbial
strep pyogenes
necrotising fasciitis features
rapid onset erythema extensive oedema pain anaesthesia over infection skin necrosis, heamorrhagic bullae systemic: fever, hypotension, tachycardia
necrotising fasciitis management
urgent surgical review - plastics for fasciotomy
necrotising fasciitis antibiotics
broad spectrum
flucloxacilin
gentamicin
clindamycin
benzyl penicillin
pyomyositis
purulent infection within striated muscle
often forms abscess
infection often 2ry to seeding damaged muscle
pyomyositis features
fever
pain
woody induration of affected muscle
pyomyositis organism and common sites
staph aureus
common sites: thigh, calf, arms, gluteal region, psoas muscle
pyomyositis predisposing factors
DM HIV IVDU rheumatological disease malignancy liver cirrhosis
septic bursitis
infection often from adjacent skin infection
most common s.aureus
septic bursitis risks
alchohilism RA DM IVDU immunosupressino renal insufficiency
septic bursitis features
peribursal cellulitis
swelling, warmth
fever
pain on movement
infection tenosynovitis
infection of synovial sheaths surrounding tendons
staph a
streptococci
infection tenosynovitis: presentation
erythematous fusiform swelling finger
held in semiflexed position
pain finger extension
tenderness over length tendon sheath
infection tenosynovitis Mx
empiric antib
hand surgeon review
what are toxin mediated syndromes often due to
superantigens - group pyrogenic exotoxins
toxin mediated syndromes pathophys
superantigens bypass APC and bind directly to T cells
massive burst cytokine release: endothelial leakage, haemodynamic shock, multi-organ failure
toxin mediated syndormes: organisms
staph a: TSST1, ETA, ETB
strep pyogenes: TSST1
which TSS organism is assoc w tampons
staphylococcal TSS
staphylococcal TSS diagnostic criteria
fever hypotension diffuse macular rash 3+ involved: liver, muscular, blood, renal, GI, CNS isolation staph a production TSST1 by isolate
streptococcal TSS
usually assoc w prescence of strep in deep seated infection e.g. erysipelas, necrotising fasciitis
urgent surgical debridement
TSS Rx
IV fluids remove offending agent e.g. tampon inotropes IV Ig antib - clindamycin, vancomycin
panton-valentine leucocidin toxin
staph a
recurrent boils, heamorrhagic pneumonia
panton-valentine leucocidin toxin antibiotica
vancomycin, linezolid
staphylococcal scalded skin syndrome
Infection due to a particular strain of staph aureus producing the exfoliative toxin A or B
cellulitis antibiotics
- fluclocacillin
- clarithromycin (penicillin allergy)
if pregnant - erythromicin
