Dermatologic Terminology
Skin
• The skin is often known as "the largest organ of
the human body".
• For the average adult human, the skin has a
surface area of between 1.5-2.0 square meters,
most of it is between 2-3 mm thick.
• The average square inch of skin holds 650 sweat
glands, 20 blood vessels, 60,000 melanocytes, and
more than a thousand nerve endings.
Primary lesions
• Most skin diseases begin with a basic lesion that is
refererd to as primary lesion. The secondary
lesions follow the primary ones.
• Macula
• Papula
• Nodule
• Urtica, wheal
• Vesicle, bulla
• Pustula
Macule
• flat, nonpalpable circumscribed area of change in
the skin. Macules are < 1-2 cm in size.
1. Macules may be the result of
• (A) hyperpigmentation (e.g. brown as in lentigos),
• (B) depigmentation (e.g. vitiligo),
• (C) vascular dilation (e.g. erythema)
Red macula
• Purpura- lesion caused by extravasated red
blood cells (due to vascular or platelet
disorder).
• Diascopy: the application of pressure with a
glass slide on the red lesion. If the redness
remains under the pressure of the slide, the
lesion is purpuric.
Papule:
• small solid elevation of skin generally < 5 mm in
diameter.
• Papules may be: flat-topped, as in lichen planus;
• dome shaped, as in xanthomas;
• spicular, if related to hair follicles.
Papules may result from:
• dermal metabolic deposits,
• localized dermal cellular infiltrates,
• localized hyperplasia of dermal or epidermal
cellular elements.
Nodule:
• palpable, solid, round, or ellipsoidal lesion.
• Its depth of involvement and/or palpability
differentiate it from a papule rather than its diameter
(although nodules are usually larger than papules: >
5 mm diameter).
• Nodules can involve any layer of the skin and can be
edematous or solid. Based on the anatomical
component(s) involved, there are five types of
nodules: epidermal, epidermal-dermal,
dermal, dermal-subdermal, and subcutaneous.
Lichenification:
• Is defined as an inflammatory
thickening of the skin with
exaggeration of the normal relief and
deepening of the natural creases.
May be due to persistent scratching.
• Itching.
Papillomatosis (warty)
• An alongation and widening
sometimes also branching of the
papillary body of the dermis. It is
cauliflower-like lesions. The surface
consisting of minute finger-like or
normal projections.
Vesicle (blister):
• circumscribed, elevated lesion that is < 5 mm in
diameter containing serous (clear) fluid.
• Bulla: A vesicle with a diameter > 5 mm.
•
Fluid can be accumulated within or below the
epidermis.
•subcorneal vesicle - fluid
just below stratum
corneum, extremely fragile
leading to crushing
intraepidermal vesicle
acantholytic vesicles) - cleavage within
epidermis due to intercellular
attachment loss,
•Subepidermal vesicle due to
changes in dermal-epidermal
junction. Vesicles have arisen
on normal or erythematous
skin.
Pustule:
• superficial, elevated lesion that contains pus (pus
in a blister).
• Pustules may vary in size and shape.
• The color may appear white, yellow, or greenishyellow depending on the color of the pus.
• Pus is composed of leukocytes with or without
cellular debris. It may also contain bacteria (non
sterile) or may be sterile (leukocytes only).
Urtica, wheal:
• Is a flattopped elevated lesion due to edema in
the upper dermis. The epidermis is not affected.
Wheals are transient and may last only a few
hours.
• Wheals can be pale red or white (especially in the
center) if edema is sufficient to compress
superficial vessels. Wheals are a common
allergic reaction.
• usually itches.
Angioedema: is a deep, edematous urticarial
reaction that occurs in areas with very loose
dermis and subcutaneous tissue (lips, eyelids).
SECONDARY LESOINS
• Result from the natural evolution of primary lesions
(eroded area left by bursting vesicle) or from the
patient's manipulation of the primary lesion
(scratching).
• Scale
• Crust
• Erosion
• Fissure, rhagas
• Eschara
• Ulcer
Scale:
• accumulation or abnormal shedding of
horny layer keratin (stratum corneum) in
perceptible flakes. The change may be
primary or secondary. Scales usually
indicate inflammatory change and
thickening of the epidermis. The may be
fine, as in pityriasis; white and silvery, as
in psoriasis; or large and fish-like, as in
ichtyosis.
• Scales: dry or oily (greasy)
Crust:
• dried serum, blood, or pus on the
surface of skin.
Crusts are yellow, if from serum;
green or yellow-green if from pus; or
brown or dark red if formed from
blood.
Crusts that occur as honey-coloured,
delicate, glistening particulates are
typical of - Impetigo.
Erosion:
• A focal loss of epidermis
• erosion do not penetrate below the
dermoepidermal junction and
therefore heal without scaring.
• Excoriaton is a shallow abrasion
often caused by scratching.
• Erosion follow blisters or papula
Fissura, rhagas:
• Is a linear cleavage or cracks of
epidermis and dermis with sharply
defined nearly vertical walls. It is
linear split at an orifice (angle of the
mouth or anus), or along a shin
crease due to dry skin palms and
soles). They may be painful.
Eschara:
• Well defined or circumscribed
necrosis skin due to trauma
(burning, frostbite, freezing,
chilblain), or ischemia in vascular
disorder (DM, microangiopathy).
Color is black.
Ulcer:
• circumscribed area of skin loss
extending through the epidermis and
at least part of the dermis (papillary).
• Basically, it's a "hole in the skin".
• Ulcer is healing with scaring.
Morphology of ulcer:
• Site
• Number
• Size (cm)
• Shape
• Depth (mm)
• Base
• Border
• Surrounding skin
Scar, cicatrix:
• A permanent fibrous skin lesion,
healed dermal lesion secondary to
trauma, surgery, infecion. Skin
appendages are absent. Scars may
are atrophic or hypertrophic
Atrophy:
• Depresion of the surface caused by
regressive changes involving the
thinning of the epidermis or dermis
and loss of the skin appendages,
blood vessels are easilly seen under
the skin, often the fine surface is
wrinkling.
Rigid atrophy, sclerosis:
• Hard atrophy often adhering to
• the tissue below, skin appendages
are absent, the surface is mirror-like
Elephanthiasis:
• A shapeless swelling and thickening
due to chronic lymphatic obstruction
and reactive fibrosis, inflammation
with connective tissue proliferation.
Impregnation:
• The deposition ion the skin of alien
particles ( ink – tatoo, gold –
chrysiasis)
Incrustation:
• The deposition in the skin of proper
particles ( calcium salts – calcinosis)
DISTRIBUTION
•
•
•
•
•
Solar
Seborrhoeic
Intertriginous
Embolic
Predilection
Solar:
• Site of exposure to sunshine – the
face (nose, ears, forehead, cheeks,),
neck, upper part of the sternum,
dorsum of the hands
• Disorders: photodermatosis, lupus
erythematosus, porphyria
Seborrhoeic:
• Regions containing large sebaceous
glands – centrofacial area –
forehead, nose, nasolabial folds,),
sternal and interscapular regions,
shoulders
• Disorders: acne, seborrhoeic
dermatitis, seborrhoeic warts
Intertriginous:
• Regions of the skin folds – the
axillae, submammary, folds of the
neck, intergluteal fold, interdigital,
inguinal regions
• Disorders: candidosis, intertrigo,
napkin dermatitis, mycotic infection
Embolic:
• Lateral part of the trunk, medial part
of the extremities. The lesions are
symmetrically distributed.
• Disorders: drug eruptions, viral
exanthemas
Predilected:
• Favourite site
• Psoriasis: knees, elbows, scalp,
limbosacral area
• Lichen ruber planus: flexural part of
the wrist , oral cavity
• Acne: face, trunk, shoulders
Configurations of the skin lesions:
• Discrete – a few lesions separated by normal
skin from the similar ones – solitary or single
• Group – multiple lesions grouped in one area:
• 1- linear – arranged in line (lichen, warts)
• 2- anular – ring-like (mycotic infection
• 3- circinar – coalescent of several anular
lesions
• 4- semicircinar – arranged in a semicircle,
half-moon - like
Configurations of the skin lesions:
• 5- serpiginous – snake-like
• 6- herpetiformis – several blisters grouped
together in one lesion (hepres simplex)
• 7-zosteriformis – lesions arranged in the
belt-like (herpes zoster)
• 8- iris – target-like
• 9- geographic – large lesions looking like
a map
• Disseminated – widespread discrete
lesions
• Generalised – widespread, all parts of the
body