Superficial and necrotic infections 3 Flashcards
what is the most common superficial skin infection?
impetigo
typical occurrence age of impetigo
any age but common in pre school
what can cause impetigo
minor trauma
where do we carry the bacteria which can cause it
the nasal passage which migrates to other parts of the face
typical causative organism?
a less common cause?
typically S.aureus
can be GAS but this is less common
summer has _____ cases than winter. why?
more
association with insect bites
2 forms of impetigo
which is more common
bullous impetigo (30% of cases) and non bullous (70%)
difference in clinical presentation of bullous and non bullous impetigo
bullous tends to see small blisters containing a clear yellow liquid on the skin
non-bullous are flatter crusts on the skin surface
universally bullous is caused by?
S.aureus
can all S. aureus cause bullous impetigo? explain
no
must produce exfoliative toxin A
what must the S.aureus be specific for to cause bullous impetigo
desmoglein 1
it cleaves desmoglein 1 and causes detachment of the skin layer to aid movement to deeper layers
desmoglein 1 is predominantly expressed where? what is expressed in the lower layers? effect?
outer skin layers- anchors the two layers to the deeper stratum
D-3 is more abundant in the lower layers
why doesn’t S.aureus effect the deeper layers
produces exfoliative toxin A which is specific for D1 but not D3 in the deeper layers
TF impetigo is self limiting
true if its uncomplicated
how to treat mild localised impetigo
fusidic acid for 5d TDS
in mild localised treatment of impetigo by fusidic acid, its use is _____ spectrum
staphylococcal agent- narrow spectrum
for bullous or widespread impetigo what do we treat it with?
oral flucloxacilin for 7d QDS or clarithromyin if penicillin allergy
flucloxacillin drug class?
beta lactam
what to do if after treatment there’s no improvement to impetigo?
swab for microbiological cause
can give something more specific
what is a generalised form of bullous impetigo that’s very rare?
staphylococcal scalded skin syndrome
why does SSSS not occur in adults
renal function can remove the toxin
difference in toxin in the SSSS and impetigo
same toxin but its more widespread
children with SSSS: their temperature regulation and fluids are affected how?
poor temperature regulation and fluid loss
in SSSS where is the primary infection site typically? what does this mean for testing for the causative bacteria?
somewhere distal to the skin
wouldn’t find the bacteria by taking a skin swab
