Superficial and necrotic infections 3

Question 1

what is the most common superficial skin infection?

Answer 1

impetigo

Question 2

typical occurrence age of impetigo

Answer 2

any age but common in pre school

Question 3

what can cause impetigo

Answer 3

minor trauma

Question 4

where do we carry the bacteria which can cause it

Answer 4

the nasal passage which migrates to other parts of the face

Question 5

typical causative organism?

a less common cause?

Answer 5

typically S.aureus

can be GAS but this is less common

Question 6

summer has _____ cases than winter. why?

Answer 6

more

association with insect bites

Question 7

2 forms of impetigo

which is more common

Answer 7

bullous impetigo (30% of cases) and non bullous (70%)

Question 8

difference in clinical presentation of bullous and non bullous impetigo

Answer 8

bullous tends to see small blisters containing a clear yellow liquid on the skin
non-bullous are flatter crusts on the skin surface

Question 9

universally bullous is caused by?

Answer 9

S.aureus

Question 10

can all S. aureus cause bullous impetigo? explain

Answer 10

no

must produce exfoliative toxin A

Question 11

what must the S.aureus be specific for to cause bullous impetigo

Answer 11

desmoglein 1

it cleaves desmoglein 1 and causes detachment of the skin layer to aid movement to deeper layers

Question 12

desmoglein 1 is predominantly expressed where? what is expressed in the lower layers? effect?

Answer 12

outer skin layers- anchors the two layers to the deeper stratum

D-3 is more abundant in the lower layers

Question 13

why doesn’t S.aureus effect the deeper layers

Answer 13

produces exfoliative toxin A which is specific for D1 but not D3 in the deeper layers

Question 14

TF impetigo is self limiting

Answer 14

true if its uncomplicated

Question 15

how to treat mild localised impetigo

Answer 15

fusidic acid for 5d TDS

Question 16

in mild localised treatment of impetigo by fusidic acid, its use is _____ spectrum

Answer 16

staphylococcal agent- narrow spectrum

Question 17

for bullous or widespread impetigo what do we treat it with?

Answer 17

oral flucloxacilin for 7d QDS or clarithromyin if penicillin allergy

Question 18

flucloxacillin drug class?

Answer 18

beta lactam

Question 19

what to do if after treatment there’s no improvement to impetigo?

Answer 19

swab for microbiological cause

can give something more specific

Question 20

what is a generalised form of bullous impetigo that’s very rare?

Answer 20

staphylococcal scalded skin syndrome

Question 21

why does SSSS not occur in adults

Answer 21

renal function can remove the toxin

Question 22

difference in toxin in the SSSS and impetigo

Answer 22

same toxin but its more widespread

Question 23

children with SSSS: their temperature regulation and fluids are affected how?

Answer 23

poor temperature regulation and fluid loss

Question 24

in SSSS where is the primary infection site typically? what does this mean for testing for the causative bacteria?

Answer 24

somewhere distal to the skin

wouldn’t find the bacteria by taking a skin swab

Question 25

how does SSSS occur?

Answer 25

toxin A is in the blood io has a more wide spread effect