Inflammatory Skin Disease + Infection Flashcards
what type of topical treatment is a semisolid emulsion of oil in water?
cream
what type of topical treatment is a semisolid grease/oil?
ointment
what type of topical treatment is a suspension/solution of medication in water, alcohol or other liquid?
lotion
what type of topical treatment is a semi-solid, thickened, aqueous lotion containing high molecular weight polymers?
gel
what is the purpose of an emollient?
enhances rehydration of epidermis
in what type of skin conditions are emollients prescribes?
dry/scaly conditions
in what type of skin conditions are wet wrap therapies prescribed?
very dry (xerotic) skin
compare the routes of antiviral administration for herpes simplex (eg cold sore or genital wart), eczema herpeticum, herpes zoster (shingles)?
HSV (cold sore/wart)- topical antiviral
eczema herpeticum- oral antiviral
herpes zoster- oral antiviral
what is hyperkeratosis?
increased thickness of keratin layer
what is parakeratosis?
persistence of nuclei in the keratin layer?
what is acanthosis?
increased thickness of epidermis
why does parakeratosis occur?
cells turn over more quickly, no time for nuclei to disappear
what is papillomatosis?
a type of acanthosis (increased thickness of epidemis) where you get wiggly epidermis (ie irregular)
what is spongiosis?
oedema between keratinocytes
why does spongiosis occur?
water has leaked out of keratinocytes because of inflammation
is papillomatosis a feature of eczema?
no
is spongiosis a feature of eczema?
yes
what happens to the dermatitis/eczema plaques in the chronic phase? (ie after itching)
thicken (lichenification) and become elevated
what is the pathogenesis of the contact allergic type of dermatitis?
delayed type 4 hypersensitivity reaction
what is the pathogenesis of the contact irritant type of dermatitis?
non-specific trauma
what is the pathogenesis of the atopic type of dermatitis? (eczema)
genetics + environmental factors causing inflammation
what is the pathogenesis of the drug-related type of dermatitis?
type 1 (IgE mediated) or type 4 (delayed) hypersensitivity reaction
what is the pathogenesis of the photo-induced/photosensitivity type of dermatiits?
reaction to UV light
what is the pathogenesis of the lichen simplex type of dermatitis?
physical trauma to scratching the skin
what is the pathogenesis of stasis dermatitis?
physical trauma to hydrostatic pressure
ie can be caused by immobility- hydrostatic pressure within blood vessels causes oedema then dermatitis
when the cause of contact allergic dermatitis is not clear, what test can be done?
patch testing
describe the plaques of atopic eczema?
ill-defined red and scaly
what type of distribution is seen in atopic eczema?
mainly flexural distribution
in the very young it can be on extensor surfaces
what is excoriation?
breaks in skin caused by scratching
what is the most common cause of secondary infection of atopic eczema? (ie after excoriation)
staph aureus
what is a typical sign of staph aureus secondary skin infection? (ie after excoriation)
crusting
what is the classic feature of eczema herperticum?
monomorphic punched out lesions
what does monomorphic mean?
each lesion is of the same size
what is discoid eczema?
eczema with well-defined lesions
what is the most common contact allergen in the UK?
nickel
what is pompholyx eczema?
eczema restricted to hands and feet
is pompholyx eczema acute or chronic?
always acute
compare Staph aureus to all other Staph species in terms of presence of coagulse?
Staph aureus = coagulase positive
all other staph = coagulase negative
what species of Staph is known as golden Staph?
Staph aureus
what is the function of coagulase?
an enzyme which Staph aureus contains
clots plasma
what type of Staph causes UTIs in women of child bearing age/
Staph. saprophyticus
what are the 2 important categories of beta-haemolytic strep?
group A strep (strep pyognes)
group B strep
what are the 2 important categories of alpha-haemolytic strep?
strep pneumoniae
strep viridans
where do non-haemolytic Strep commonly cause infection?
urinary tract infections
where in the body are non-haemolytic Strep commensals?
bowel
what are the 2 most common pathogens causing impetigo?
Staph aureus
GAS (strep pyogenes)
what population does Staphylococcal scalded skin syndrome usually occur in?
neonates
what pattern of redness does erysipelas give?
butterfly pattern
why can’t you tell whether the cause of erysipelas is Staph or Strep?
blood cultures are usually negative, no swabs available
what type of characteristic pain is seen with necrotising fasciitis?
pain disproportionally high to what can be clinically seen
what is the antibiotic of choice for treating sensitive strains of Staph aureus?
flucloxacllin
in addition to antibiotics, what else is required for the treatment of necrotising fasciitis?
immediate surgical debridement
what are the 2 types of necrotising fasciitis?
- caused by mixed anaerobes and coliforms
2. GAS