Skin and soft tissue infections Flashcards
Erysipelas pathogens
Group A Streptococci or Streptococcus pyogenes
Superficial skin infection, doesnt involve subcut tissue
Erysipeloid pathogen
Erysipelothrix rhusiopathiae
Mild cutaneous infection
Erysipeloid source
carried by pigs and fish (more in vets and farmers)
Erythrasma pathogen
Corynebacterium minutissimum
Brown scaly skin patches
Who gets erythrasma
rare, mainly in children
cellulitis pathogen
Varies:
eg S aureus or group A strep
Erysipelas affects which part of body?
80% of cases affect the lower extremities,
20% the face.
Rfs for skin infection
lymphoedema, venous staisis, obesity, diabetes, EtOH.
Scarlet fever pathogen?
S. pyogenes
when does desquamation occur with scarlet fever?
occurs 2-5 days after the scarlatiniform rash.
Complications caused by scarlet fever
- scalded skin syndrome
2. toxic shock syndrome
Scalded skin syndrome presentation
- looks like someone was dumped in a bath of scalding water (caused by toxins released by the bacteria)
- skin easily comes off:
Risk with scalded skin syndrome
increased risk of infection, increased dehydration
Cellulites def
An acute spreading infection of the skin extending deeper than erysipelas and involves the subcutaneous tissues
Cellulites mx?
- should include antibiotics active against the most common isolates.
Eg. Flucloxacillin, Benzyl-penicillin.
Necrotising fascitiitis def
infection involving the subcutaneous soft tissues, particularly the superficial and often deep fascia.
2 types of Necrotising fascitiitis pathogens
Type I
- polymicrobial,
- deep infections, if on foot, more likely to be skin, if around abdomen, more likely to be abdomenal flora
Type II = Streptococcus pyogenes
RFs for type 1 Necrotising fascitiitis
EOH, elderly, male
RFs for type 2 Necrotising fascitiitis
IVDU
Initial sx of nec fascitiis
- very tender in the early stages,
- erythematous and swollen,
- rapidly progressing to skin breakdown and bullae formation within 3-5 days.
Late sx of nec fascitiis
- Frank cutaneous gangrene,
- area becomes anaesthetic secondary to thrombosis of small blood vessels and destruction of superficial nerves.
Mx of nec fasciitis
High dose benzyl-penicilin PLUS flucloxacillin PLUS metronidazole
(depends on the pathogen)
GAS gangrene caused by
Usually the result of trauma, May also occur after bowel surgery
GAS Gangrene pathogen?
Clostridium perfringens
(Contamination of wound with spores, they multiply producing gas),
