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so the next thing we're gonna talk about
is bullish disorders let's jump into a
case this is a 71 year old woman with a
past medical history of obesity who's
presenting with progressive skin rash
she reports she noted the development of
itchy hives randomly distributed over
her body several months ago that seemed
to wax and wane leaving reddish patches
on her skin five days ago she noticed a
tense fluid filled blister on her right
thigh that seemed to emerge from one of
those red patches followed by two
similar lesions on her torso
now she denies any lesions in her mouth
no fevers no chills no nausea she takes
only atorvastatin and lisinopril and
denies taking any new medications social
history nonsmoker she drinks a couple
beers most days of the week
non-contributory family history and on
review of systems no dyspnea no eye
symptoms no joint pain so highlighting a
few key aspects that we think of when
addressing a new case the time course
appears to be slowly progressive we've
been seeing these symptoms slowly evolve
over several months the pattern of skin
involvement seems kind of random there's
no particular predilection and it's not
symmetric skin inflammation does appear
to be present with some developing
blisters in different areas and there
doesn't appear to be any evidence of
systemic involvement at this time based
on a pretty negative review of systems
physical exam she's got a temperature of
37 point one degrees Celsius our rate 72
blood pressure 135 over 71 had a neck
exam normal conjunctiva no lymph
adenopathy no oral pharyngeal lesions
and then on the skin exam we see
scattered non-tender erythema dhis
examine dispatches in both sun exposed
and unexposed areas there are numerous
tents bully one to three centimeters in
size on her torso and on her extremities
containing either serous or hemorrhagic
fluid some of those Bolle are emerging
from erythema Dispatches others are
emerging de novo from normal
skin and just a slight rubbing of the
affected skin does not lead to any
exfoliation I think we'll learn about
the significance of that in a little bit
and no evidence of significant edema the
picture shown here is not a picture of
our patient but a representative photo
of what we're looking at so based on the
information we have thus far which of
the following is the most likely
diagnosis let's take a look at each one
so stevens-johnson syndrome
now stevens-johnson syndrome we know
that half of the time 50% of cases are
not related to drug exposure and they're
either idiopathic or they might be
related to some prior antecedent
infection most commonly mycoplasma or
potentially HSV stevens-johnson syndrome
is characterized by lesions that may
initially include erythema despatches as
we're seeing in our case and it really
lies on a spectrum from stevens-johnson
syndrome up to toxic epidermal
necrolysis so it's something that still
keep on our list for sure even though
we're not getting a story of any new
medications and no obvious prior
infections porphyria cutanea tarda there
are a number of different porphyria's
that are out there this is the one that
has the most common skin manifestations
it is a skin disease associate with
adulthood and it's essentially caused by
a disruption of the normal heme
biosynthesis pathways and that's the
same for all the porphyria's depending
upon where the disruption in the heme
biosynthesis pathway occurs that's when
you're going to get a different
phenotype of porphyria whether it's very
good porphyria or acute intermittent
porphyria or in this case PCT
importantly it is characterized by the
gradual progression of per itis with
vesicles and ballet but it really tends
to occur in sun-exposed areas because
it's the intersection between sun
exposure and these toxic poor furyk
proteins that lead to the manifestations
of disease we're not really getting much
of that in this case but we'll keep it
on the list for now
next up bullous pemphigoid it does
affect the elderly our patient is in her
70s it does cause tense Bolle and we'll
talk about why in a moment
and so I think
we'll need to keep that one on our list
pemphigus vulgaris this is a potentially
very severe disease process that can
have significant consequences it's often
associate with significant mucosal
involvement our patient at the moment is
not appearing to have any mucosal
involvement but we'll keep that one on
the list nonetheless we have to make
sure we rule it out and then
staphylococcal scalded skin syndrome
it's definitely characterized by diffuse
ill-defined erythema Dispatches as was
the case in our patient and then they
can progress to extensive epidermolysis
or sloughing of skin and bullae though
there is something about staphylococcal
scalded skin syndrome that just doesn't
seem appropriate for our case I'll have
to come back to that one let's highlight
a few key points here so this is clearly
a 71 year old woman and when we think
about something like bullous pemphigoid
which is perhaps right now the highest
thing on my list it is a disease of the
elderly there's really an equal male to
feel for male to female predominance
there there is oftentimes with bullous
pemphigoid a prodrome of paretic hives
some papules some Examiners patches
which can be present for months before
you even see any of those bullous
lesions occur and that is something that
we're getting from our patient thirdly
one of the characteristic features of
bullous pemphigoid in contrast to say
pemphigus vulgaris is the absence of
mucosal involvement it can occur but
it's much less likely to be seen with
bullous pemphigoid fourth no fevers
chills or nausea that's also typical of
bullous pemphigoid
some of those other things on our list
very frequently have systemic
involvement but constitutional symptoms
and things like that would not be a part
of bullous pemphigoid
so all these factors are really steering
us towards that diagnosis likewise in
terms of where head neck exam normal
conjunctiva no oropharyngeal lesions
further supports the idea that the
mucosa are not typically involved the
lesions are non tender which would also
suggest a less inflammation kind of
process sun exposed and unexposed areas
again that's going to steer us away from
porphyria cutanea tarda which
you'd really only see in sun-exposed
areas the fact that the bullae are tense
this is a very very important point in
this case we'll come to why in a moment
but it has to do with where the defect
is occurring in terms of the skin layers
at this point with tense Bolle we know
that the epidermis which is outside of
the dermis appears to be intact we'll
talk more about that in a second and
there's this classic test that I was
alluding to before when you rub the
affected skin and it does not separate
you're not immediately separating the
dermis from the epidermis or separating
the epidermis itself that's called a
negative Nichole ski skin and the
Nichole ski sign can be something that
can help us steer us towards one disease
or another and we'll talk about that as
we go through this conversation so with
all that information in mind it looks
like we're looking at bullous pemphigoid
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