Okay. First up, is pustular psoriasis.
Now, this can be quite severe, as
you can tell from this image.
It has a predilection for the
hands and the feet --
-- the soles, that is, the soles and the palms.
And it's often interestingly
by the wrongful use of systemic steroids
to treat chronic psoriasis. As we'll see
later, when we get to treatment,
this is one of those few autoimmune
conditions for which steroids is not helpful
and may actually be quite counterproductive.
The next subtype is called
inverse psoriasis, so called because
the lesions are the
inverse of the typical plaque psoriasis.
Rather than having lesions on
the extensor surfaces,
you have them on the flexural
intertriginous creases side.
So you might have them in the axilla. You
might have them underneath the breast line,
in the intergluteal cleft, or in
the groin area.
The lesions look fairly similar
to run-of-the mill
plaque psoriasis. The difference
is that you're
unlikely to see the silvery scale.
Next up is erythrodermic psoriasis,
and this is the least common form.
It's characterized by generalized
erythema and scaling
from head to toe. As you might imagine, with
such significant involvement of the skin,
it's associated with significant
and systemic infections.
This one is also like
pustular psoriasis, often precipitated
by the injudicious use
of systemic steroids. Next up,
we're coming to the end,
is guttate psoriasis. A little etymology
point here. Guttate
comes from the same latin word that gout
comes from, which means drops.
Gout was believed to be
excess fluid or toxic
humors in the joints, and in this case,
guttate psoriasis refers to dewdrop lesions
all over the skin. They're typically
less than a centimeter in size.
You'll find them on the torso
and on the proximal extremities,
as depicted in our image
here. It may come on
fairly acutely, unlike some other forms
that are more chronic in nature.
And it's been linked with recent
for reasons that aren't entirely clear.
Next up, finally, we've reached plaque
psoriasis. Now, this is the most
common variant and the one that I
presume you're all familiar with.
It's characterized by the
of lesions to the extensor elbows,
the knees, the scalp, and oftentimes,
around the umbilicus.
And a very good example of it is
shown here in this image.
It may have features of some
of the other subtypes.
There may be some lesions in interdigital
creases, like in the intergluteal cleft.
There may be some small pustules
on the hands, as well.
Classically, there's nail involvement, and
this may involve nail pitting,
onycholysis, and a lesion called
oil spotting, which is
basically onycholysis on the nail plate.
Lastly, these lesions may
in fact be pruritic.
So that's plaque psoriasis. Okay. Having
spoken about the 5 different
subtypes of psoriasis,
I think we can say that our patient, who's
presenting with waxing and waning lesions
on his extensor surfaces of his elbows
and his knees, as well as some nail
findings that are classic, it looks like
this guy has plaque psoriasis.
So having discussed the type of
psoriasis we're looking at,
why don't we jump a little bit into
So, psoriasis is a complex
of T cells and dendritic cells,
which is leading to the hyperproliferation
Essentially, a thickening of the skin.
It can actually start at any age with an
equal male to female prevalence.
There are certain risk factors that
we should think of, though.
So smoking is a risk factor, alcohol, obesity.
Interestingly enough, TNF alpha inhibitors,
while they're sometimes used to
treat psoriasis, strangely enough
can actually manifest with
Other things to think about are
Lithium and HIV disease
is associated with worse psoriasis.
So it's important to recognize that
30% of patients who have psoriasis
will develop psoriatic arthritis
and this is one of the
axial spondyloarthritis. It's a chronic,
progressive, peripheral arthritis and
it most commonly afflicts the distal
interphalangeal joints and
the sacroiliac joints.
These are destructive, erosive lesions
and it can be quite debilitating.
Just like all the other
it is associated with the HLA B27 haplotype.
In addition, patients with psoriasis
oftentimes can develop
ocular symptoms like
scleritis or episcleritis.
Other autoimmune diseases may be
found in patients with psoriasis as well.
And as a chronic inflammatory
disease, you should also be mindful
of the increased risk of
This is really a clinical diagnosis.
There are some
classic features that we see with psoriasis,
so biopsy is rarely indicated.
So let's take a quick look at some of
the key features of this case again,
just to highlight some key points.
So this was a 33-year-old man.
That is a pretty typical demographic
for someone having psoriasis.
He states that his lesions have been
coming at various times over the
past several years. Psoriasis
is one of those
chronic relapsing remitting diseases that
typically resolving spontaneously
in the summertime. For some reason,
some patients do have symptoms that
come and go with seasonal variation.
The lesions are itchy.
This is not always the case, but certainly
these plaques can be pruritic.
The fact that he smokes a pack
per day, definitely relevant
oth by virtue of the fact that
it can increase his risk
of developing worsening
psoriasis, but also, again,
with a chronic inflammatory disease,
quitting smoking is going to be very
important to reduce his risk of
cardiovascular disease down the road.
And next, his family history is
aving an uncle with ankylosing spondylitis
means that he has a family history
of one of the axial
spondyloarthritis, which is going to
increase his risk of developing
On the physical exam, one of the
important findings that we
had commented on before was
when scraping off one of the
plaques, it caused punctate bleeding.
This is a classic finding
called Auspitz sign
and it's just something to look for
that you might find on the boards.
So let's start talking about the
management of psoriasis.
Like many conditions, we have
a stepwise approach to
addressing the problems
of psoriasis. First off,
for a limited disease, we're exclusively
going to use topical agents.
This may involve just emollients
to soften up the skin,
vitamin D analogs like, calcipotriene,
medium to high potency
corticosteroids like clobetasol,
or retinoids, like tazarotene. For moderate
to severe disease in contrast, we're
going to use topical agents
in combination with systemic therapy.
This may involve simply
PUVA, or a type of phototherapy.
We may add on
immunomodulators like methotrexate
Or we could use the biologic medications
like TNF inhibitors and
anti-IL-17 agents. Importantly,
as I mentioned before,
anti-TNF agents, ironically,
while being used to
treat psoriasis, have been shown to
sometimes exacerbate psoriasis.
So that's something that you would
necessarily have to be watching for.
Okay. So let's highlight some key
points. Psoriasis is a chronic,
relapsing, inflammatory skin
disease with multiple
phenotypes as we've discussed.
It's a T cell-mediated
hyperproliferation of keratinocytes.
It causes erythematous plaques, most
commonly with thick, silvery scale.
There are symmetric extensor
there's often going to be nail findings
with nail pitting or onycholysis.
And we're going to use a stepwise approach:
topicals, up to systemic treatment
with biologics or UV radiation.