So the next thing we're going to
talk about is bullous 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. It seemed
to wax and wane,
leaving reddish patches on her skin.
5 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 2 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: non-smoker, 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 37.1°C,
heart rate's 72, blood pressure 135/71.
Head and neck exam: normal conjunctiva, no
lymphadenopathy, no oropharyngeal lesions.
And then on the skin exam, we
see scattered, non-tender,
patches in both sun-exposed
and unexposed areas. There
are numerous tense bullae,
1-3 cm in size, on her torso
and on her extremities,
containing either serous
or hemorrhagic fluid.
Some of those bullae are
emerging from erythematous
patches. 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,
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
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 to 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
porphyrias that are out there.
This is the one that has the most
common skin manifestations.
It is a skin disease associated
And it's essentially caused by
a disruption of the normal
heme biosynthesis pathways. And that's
the same for all the porphyrias,
depending upon where the disruption
and the heme biosynthesis
pathway occurs, that's when you're
going to get a different
phenotype of porphyria,
whether it's variegete
porphyria or acute intermittent
porphyria or, in this case, PCT.
Importantly, it is characterized
by the gradual
progression of pruritus
with vesicles and bullae,
but it really tends to occur
in sun-exposed areas,
because it's the intersection
between sun exposure
and these toxic porphyric
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 bullae, 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 associated with significant
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
is definitely characterized by diffuse,
patches, 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.
We'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,
is really an equal male to female
There is, oftentimes, with
a prodrome of pruritic hives, some papules,
some eczematous 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 our 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 bullae, we know that the
epidermis, which is outside of the dermis,
appears to be intact, and 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 Nikolsky sign.
And the Nikolsky 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.