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hi i'm dr. justin cohen clinic chief of
medical dermatology at Stanford medicine
today we'll be talking about a general
approach to the dermatological nation to
describe skin lesions first we have to
learn the language of dermatology it's
the common language that we share to
describe skin lesions and this is
something we call morphology which is
describe the general appearance of a
skin lesion without any regard to its
pathogenesis where its underlying
etiology
the first thing that we have to do is we
have to identify the primary lesion
we're going to go through and talk about
the different primary lesions and
provide some clinical examples and
images of each a Mac you Elizabeth less
than one centimeter lesion and a
petechiae is an example of a Mac you'll
if you were to take a Mac Ewell and
increase its size to greater than one
centimeter we would have a patch
vitiligo is a perfect example of the
patch a raised patch something that you
could feel that's raised above the
surface of the skin is called a plaque
psoriasis is a is a great example of a
plaque if you were to take a Mac you'll
make it palpable it's still less than
one centimeter we have a papule and a
papule is something that we see to
provide by a cherry angioma or a wart in
addition you can have a large papule
something greater than two centimeters
which is dome-shaped and you call that a
nodule at the dermal inclusion cyst is a
commonly encountered nodule that we see
in the skin a vesicle is a clear fluid
filled lesion herpes is an example of a
vesicle if we have something that looks
like a vesicle but that's instead filled
with pus or purulent material we call
that a pustule and we see pustules in
acne and certain kinds of drug eruptions
a large vesicle greater than one
centimeter is called a bulla and we see
bulla in friction war in blistering
conditions like bullous pemphigoid so
after we choose the appropriate now you
have to fill it out with some adjectives
we can talk about the size of a lesion
we can talk about whether or not its
borders are clearly defined in other
words its demarcation well demarcated
lesions
such as we see an era syphilis
alternatively regions can be not well
demarcated such as in cellulitis we can
also talk about its color and in
dermatology there's a lot of conditions
which have characteristic colors to them
one example is we see the white of
vitiligo a loss of pigmentation we can
also see a bright red of a drug eruption
or a viral example in addition purple
sometimes connotes a vascular process
like Kaposi sarcoma we can also see
things in the skin that are
granulomatous appear brown in color
yellow sometimes makes us think of as
anthelmintics lesions or fatty lesions
in addition we can sometimes see black
as being necrotic skin or eschar we also
see blue as a deep pigmentation for
example in something called a blue Nevis
in addition to the primary morphologies
we oftentimes have secondary wear
overlying morphologies some of these
examples include serum which is dried
crust we can see this in potato or we
can see this in acute or subacute eczema
fissuring
is something that we can see which is a
splitting of the skin as a result of
hand or foot psoriasis we can also see
like kenefick ation by kenefick ation is
the thickening of the skin and
accentuation of skin lines as a result
of chronic rubbing or scratching
erosions are partial loss of the
epidermis and sometimes we see this as a
result of scratching or injuring the
skin ulcerations are full thickness loss
of the epidermis and sometimes these are
frictional ii derived or as a result of
other primary processes it's important
to consider the distribution of skin
lesions throughout the body as they can
help you with the diagnosis for example
lesions on the extensor surfaces of arms
and legs can be seen in psoriasis
generalized distributions occur in
certain drug reactions we could see a
photo distributed rash and connective
tissue diseases such as lupus order
madam is itis that was a lot of
information so let's quickly review the
important parts whenever you are
attempting to describe a skin problem
remember the primary lesion mer
morphology size demarcation color
secondary morphology and distribution
what you'll need for a skin examination
is a well-lit room
a ruler a magnifying glass a handheld
source of light and an open and curious
mind we have a patient here today who's
going to help us go through some of the
important considerations for a
dermatological examination hello sir
thanks for coming in thank you doctor so
using some of what we just discussed
let's practice by describing our patient
trash so the first thing we want to do
is we want to carefully choose our
primary lesion I'm going to choose this
area here when I touch it I feel that
it's raised above the surface of the
skin it's larger than a centimeter in
size so the appropriate primary lesion
term would be a plaque after we choose
our now we want to think about some
other descriptive terms that help us
fill out some of the adjectives this is
probably a few centimeters in size well
demarcated it's color is probably dully
red I would describe as in regards to
secondary morphology we see that it has
some crusting which is dried serum or
dried blood we can also see superficial
erosions where areas that the skin has
been disrupted and also we notice some
subtle scaling so taken all together
this is consistent with a diagnosis of
psoriasis this air feminists plaque with
overlying scale excoriation serum crusts
and different lesions and stages of
evolution are consistent with this
diagnosis on extensor surfaces of the
body one of the other things that we can
do sometimes is perform special tests
sometimes what we do with scaly lesions
like this is if we were to peel off some
of the scale we can see if we see an off
Spitz sign which is signs of focal
bleeding from blood vessels that are
high up in the surface of the skin the
other thing that we notice about this
stepping back from the primary lesion is
the distribution of the lesion and
looking at the legs it tends to be on
the extensor surfaces of the body so we
see that these plaques are distributed
only
mainly on the legs here but also when we
look above we see some areas of
hyperpigmentation further up on the legs
also given that psoriasis can involve
other areas one of the areas we want to
examine is the scalp
in addition we want to examine the year
including the contrl Bowl and the extra
external auditory meatus as well as the
retro auricular area other areas we want
to examine include the medial and
lateral canthus the LR groove the LR rim
under the chin the anterior neck you
also want to make sure we examine and
traditionally
always announce what body part you'll be
examining next and ask permission before
doing so I hope you enjoyed our
discussion about an approach to the
dermatological and please visit the
Stanford 25 website for more info the
preceding program is copyrighted by the
Board of Trustees of the Leland Stanford
junior University
please visit us at med.stanford.edu
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