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in this lecture we're going to talk
about erythema multiforme a and
stevens-johnson syndrome so erythema
multiforme a is a hypersensitivity
reaction it usually happens to
infections such as HSV or mycoplasma or
just viral illness rarely it can be a
drug reaction or it can be from cancer
collagen vascular disease or it may be
idiopathic and people just don't know
what's causing it the lesions may be
vesicular or bolus but usually their
target I'd lesions with a central papule
surrounded by an erythema this ring
usually around one to three centimeters
this is a particularly severe case right
here you can see generally they'll have
a carrot and iSight injury and you can
see some necrotic kureta sites here with
a lymphocytic infiltration and then the
skin you can see a sort of central area
where it's very red on a mild mild or
erythema to space so let's go through
the causes of E multiform a certainly
infections HSV and mycoplasma are most
common but also could be from
coccidioidomycosis or histoplasmosis or
typhoid or even rarely leprosy drugs can
also cause this and we usually think of
sulfa Xand penicillins but there's other
drugs such as barbiturates NSAIDs or any
antimalarials that can also cause this
reaction
likewise diseases can cause this such as
cancer or lupus or dramatic Myositis or
polyarteritis nodosa basically diseases
with a lot of antibodies the treatment
for erythema multiforme a is largely
supportive it may be itchy and we came
for antihistamines but generally this
rash is self limited and will gradually
go away on its own maybe in a week or
two there is a more severe form of this
problem which is stevens-johnson
syndrome in stevens-johnson syndrome
patients develop severe Bullis form of
erythema multiforme a with widespread
mucous membrane involvement ends
Maupin and it can be life-threatening
it's caused by generally again drug
sensitivity or infection and it's immune
mediated often about one to three weeks
after the exposure the morbidity and
mortality in stevens-johnson syndrome is
generally from dehydration or
superficial infection of the Slough skin
it can also be from toxemia or renal
damage and the rate of mortality is low
but reasonable around one to three
percent so let's talk about what this
presents like patients often have a
prodrome of fever malaise or URI
symptoms their prodrome to the illness
then they developed the rash this can
involve and must involve for a diagnosis
at least two mucous membranes they can
have severe ulceration of the mouth or
they can have significant involvement of
the conjunctivitis corneal ulceration or
even uveitis they may also have genital
involvement patients generally develop
very severe skin disease and they can
form bullae which can then slough off
and create denuded skin which can be the
source of both infection and dehydration
here's a example of very severe
keratinocyte apoptosis and epidermal
detachment so you can see the epidermis
can just lift right off so to make the
diagnosis we generally want to see the
typical lesions of target ID or atypical
skin lesions and involvement of least
two mucous membranes one sign of
stevens-johnson syndrome that might show
up is nikolsky sign nicole ski sign is
when you press down in one area adjacent
to a belay and it actually lifts the
skin away from the from the in the
affected area so this is sort of like
pressed next to it and the skin Slough
Soph that's classic for stevens-johnson
syndrome when we're worried about
patients we want to calculate the
percent of epidermal detachment this is
treated similarly to burns if a patient
has less than 10
of Stephen of body surface area involved
we call that stevens-johnson syndrome if
it's more than 30 percent it is
life-threatening and we call that toxic
epidermal necrolysis so how do we manage
stevens-johnson syndrome we want to
remove the offending agent if it's a
medication we're going to stop it if
it's mycoplasma we might treat it we
want to provide supportive care such as
wound management these patients do
better often in a place that has
experience with burns we need to provide
adequate fluid and sometimes fluid
hydration is very important in these
patients because the skin is denuded and
they have a lot of insensible losses and
since this condition can take a long
time to get better we need to provide
nutrition as well we need to provide
adequate pain management because these
patients are in a lot of pain and in
particular we want to get the
ophthalmologist involved because I care
is critical to prevent any future of his
vision deficit
lastly we may try potential adjunctive
therapies steroids typically do not work
people sometimes will try IVIG to try
and mitigate somewhat the autoimmune
nature of this disease so that's a quick
summary of a multi for may and
stevens-johnson syndrome thanks for your
attention
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