SKIN DISEASES LECTURE

1. SKINDISEASES

2. DESCRIBING SKIN LESIONS
PRIMARY MORPHOLOGY
>FLAT VS RAISED
>SIZE
>CONSTITUENCY
SECONDARY MORPHOLOGY
>COLOR
>SHAPE
>TEXTURE
>LOCATION

3. PRIMARY MORPHOLOGY
FLAT
RAISED
MACULE
PATCH
PAPULE
PLAQUE
SKIN LESION

4. RAISED
LIQUID FILLED
PUS FILLED
SOLID
CONTITUENCY
Pustule: a circumscribed,
elevated lesion filled with
purulent fluid, less than 1 cm
in size (e.g. erythema toxicum
neonatorum, acne). Vesicle: a
circumscribed, elevated, fluid-
filled lesion up to 1 cm in size
NODULE - A palpable, solid lesion
that is greater than 10 mm* in
diameter. Nodules are usually
found in the dermal or
subcutaneous tissue, and the
lesion may be above, level with, or
below the skin surface. Example:
Dermatofibroma. TUMOR - A solid,
firm lesion that is typically greater
than 20 mm in diameter.

5. SKIN BLEEDING(non-blanchable)
Purpura is small, flat spots on your
skin. They look red or purple on
lighter skin tones but appear brown
or black on darker skin tones.
Purpura is commonly referred to as a
blood spot under your skin. Purpura
usually consists of smaller dots that
cluster in a specific area but may
appear as one larger patch.May be
palpable. 3-10mm
Ecchymosis is usually caused
by an injury, such as a bump,
blow, or fall. This impact may
cause a blood vessel to burst
open leaking blood under the
skin, creating a bruise. While
bruises are very common and
affect almost everyone, women
tend get them more easily than
others do.More than 10mm
Petechiae are pinpoint, round
spots that appear on the skin
as a result of bleeding. The
bleeding causes the petechiae
to appear red, brown or
purple. Petechiae commonly
appear in clusters and may
look like a rash. Usually flat to
the touch, petechiae don't
lose color when you press on
them.They are Non-Palpable

6. Telangiectasias are
small, widened blood
vessels on the skin.
They are usually
harmless, but may be
associated with
several diseases
Urticaria – also known as
hives, weals, welts or
nettle rash – is a raised,
itchy rash that appears on
the skin. It may appear on
one part of the body or be
spread across large
areas. The rash is usually
very itchy and ranges in
size from a few
millimetres to the size of a
hand.
Skin ulcers are open sores
caused by poor blood
circulation. If you have poor
blood circulation, then minor
wounds (that otherwise would
heal quickly) may not heal
properly leaving that injury to
develop into a painful skin ulcer.
These sores and ulcers often
become infected if not properly
treated.

7. “SCRATCH
MARKS”EROSION
OF THE SKIN
THAT IS LINEAR IN
SHAPE
EXCORIATION
Scales are a visible peeling or
flaking of outer skin
layers(EPIDERMAL
THICKENING. These layers
are called the stratum
corneum. This view shows
the red, scaly patches called
plaques that are
characteristic of atopic
dermatitis.
An actinic keratosis is a
thick, scaly, or crusty skin
patch that's typically less
than 2 centimeters (cm), or
about the size of a pencil
eraser. It appears on parts
of the body that receive a
lot of sun exposure (the
hands, arms, face, scalp,
and neck).

8. SECONDARY MORPHOLOOGY
SHAPE
ROUND
LINE
COIN-SHAPED
Annular skin lesions are figurate
lesions characterized by a ring-like
morphology. Although plaques
represent the most common
presentation of annular lesions,
lesions may also be macular,
nodular, or composed of grouped
papules, vesicles, or pustules.
Linear lesions act as diagnostic
clues in many disorders. They also
help in elucidating the
pathogenesis as they give a clue to
the pathway of spread of the
disease. Koebner phenomenon
indicates the presence of active
disease and helps to decide the
line of management.(eg:CONTACT
DERMATITIS)
Nummular eczema is a skin
condition that causes
circular, raised spots on
your skin. Nummular comes
from a Latin word for “coin,”
and the patches are coin-
shaped. The lesions are
often itchy, sometimes ooze
clear fluid and may become
crusty on top. The condition
is chronic.

9. OTHER SHAPES
TARGET
WEB-LIKE SNAKE LIKE
A target lesion is a round skin lesion with
three concentric colour zones:
=A darker centre with a blister or crust
=A ring around this that is paler pink and
raised due to oedema (fluid swelling)
=A bright red outermost ring.
Target lesions typically occur in
erythema multiforme. They can arise on
any body site, including face, upper
chest, back, arms, legs, hands, feet and
mucous membranes (such as the lips). A
target lesion is also called a bulls-eye
lesion or a cockade (a rosette pattern of
concentric rings).
RETICULAR
“reticulate” is used for
clinical description of
skin lesions that are
configured in a net-
like pattern. “LAZY
NETWORK”also
known as Livedo
reticularis
Serpiginous “Squiggly”branching
lesion.(Parasitic Infection)
Cutaneous larva migrans (CLM) is a
serpiginous eruption that can occur
anywhere on exposed body parts
but is usually confined to the skin of
the feet. It is most often caused by
dog and cat hookworms, which are
types of nematodes (roundworms).

10. HERPETIFORM IS CLUSTER OF
PAPULES OR VISICLES
Dermatitis herpetiformis (DH) is a
chronic, intensely itchy, blistering
skin manifestation of gluten-
sensitive enteropathy, commonly
known as celiac disease. DH is a
rash that affects about 10 percent
of people with celiac disease.
Zosteriform vesicular
lesions of the skin could
be due to either herpes
zoster (caused by
varicella zoster virus) or
zosteriform herpes
simplex (caused by
herpes simplex virus).

11. SECONDARY MORPHOLOOGY
TEXTURE
Hyperkeratosis is the skin's
response to rubbing or
irritation. A corn or callus on
your hands or feet.
A bump or patch of thickened
skin is known as a
hyperkeratotic lesion.
TINEA PEDIS
Verrucous lesions are
defined as “pertaining
to or marked by wart
like growth pattern.”
SEBORRHEIC
KERATOSIS
=WARTS
Lichenification is a secondary
skin lesion that is characterized
by hyperpigmentation, thickening
of the skin and exaggerated skin
lines. These skin lesions usually
appear from constant scratching
or rubbing in areas, such as the
elbows.

12. SECONDARY MORPHOLOOGY
TEXTURE
Xanthomas are lesions on the
skin containing cholesterol
and fats. They are often
associated with inherited
disorders of lipid metabolism
(inherited problems with the
way that fats are broken
down and used). Xanthomas
are raised, waxy-appearing,
frequently yellowish-colored
skin lesions.
Induration refers to the
thickening and hardening of
soft tissues of the body,
specifically the skin, and is the
result of an inflammatory
process caused by various
triggering factors. Indurated
areas commonly appear on the
hands and face but can also be
found on the chest, back,
abdomen, breasts, or buttocks.
UMBILICTED
Molluscum contagiosum virus
causes characteristic skin lesions
consisting of single or, more often,
multiple, rounded, dome-shaped,
pink, waxy papules that are 2-5
mm (rarely up to 1.5 cm in the
case of a giant molluscum) in
diameter. The papules, or bumps,
are umbilicated and contain a
caseous plug.