Introduction to Dermatology
By
Stacey Singer-Leshinsky R-PAC
What is?
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Dermatology?
Dermatologist?
Functions of the Skin
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SensationImmune functionThermoregulationCutaneous absorption
Functions of the Skin
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Excretion
Vitamin D synthesis
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UV light for 10-15 minutes.
Skin Anatomy
Layers
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Epidermis- outermost, no blood vessels or
blood supply.
Dermis- vascular layer/sensation. Strength
and elasticity to skin.
Hypodermis or subcutaneous layer.
Skin Anatomy
Epidermis-5 Layers
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Stratum corneum-
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Stratum lucidum
palms and soles of feet
only.
Skin Anatomy
Epidermis-5 Layers
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Stratum granulosum
Most differentiated layer.
Skin Anatomy
Epidermis-5 Layers
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Stratum spinosum
Has desmosomes (spiny
projections and so
spinosum).
Skin Anatomy
Epidermis-5 Layers californians like girls in
string bikinis)
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Stratum basale
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deepest layer of the
epidermis.
Consists of a single layer of
keratinocytes.
Skin Anatomy
Epidermis-Cell Types
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Melanocytes
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Produce melanin. Not many melanocytes
in soles or palms.
Albinos lack tyrosinase
Cancer of a melanocyte known as
melanoma
Skin Anatomy
Epidermis-Cell Types
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Keratinocytes
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Produce keratin
Immunology roleProtection and water proofing
Merkel’s cells- Free nerve endings
attached to epidermal cells.
Skin Anatomy
Epidermis-Cell Types
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Langerhans cells
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Found in epidermal layers with keratinocytes
Involved in cell-mediated hypersensitivity, antigen
processing and recognition, stimulation of immune
competent cells and graft rejection.
Skin Anatomy
Epidermis-Cell Types
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ParakeratosisRetention of nuclei in
stratum corneum.
SpongiosisIntercellular edema of
the epidermis.
Skin Anatomy
Basement membrane(Basal lamina)
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Selectively filters molecules
moving between two
layers.
Immunoglobulin and
complement deposition in
skin disease.
Skin Anatomy
Dermis
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Thickest skin
layer/connective tissue
layer.
Composed of collagen,
blood vessels, nerves,
hair follicles, and sweat
glands
Skin Anatomy
Subcutaneous Tissue
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Eccrine glands and
deep hair follicles
extend to this layer
Insulator/shock
absorber/stores
energy as calories
Skin Anatomy
Appendages-Hair
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Hair follicle associated with
sebaceous gland to form
pilosebaceous unit.
Growth is cyclic
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Anagen phaseCatagenTelogen phase-
Skin Anatomy
Appendages-Hair
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Hair loss due to:
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Skin Anatomy
Appendages-Nails
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Hardened keratinized plates
Skin Anatomy
Appendages-Glands
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Sebaceous- Entire
skin surface except
palms, soles, sides
of feet. Secrete
sebum
Skin Anatomy
Appendages-Glands
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Sweat glands
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Eccrine-Originate in
dermis and open on
skin surface.
Apocrine- Large, deep
in dermal layer. Open
through a hair follicle.
Mostly in axillae and
groin.
Common Skin Lesions
Equal to plane of the Skin
Common Skin Lesions
Equal to plane of the Skin
Telangiectasia-
Common Skin Lesions
Equal to plane of the Skin
Petechiae-
Common Skin Lesions
Equal to plane of the Skin
Purpura or ecchymosis:
Common Skin Lesions
Equal to plane of the Skin
Sclerosis:
Common Skin Lesions
Equal to plane of the Skin
Lichenification:
Common Skin Lesions
Equal to plane of the Skin
Acanthosis
Common Skin Lesions
Above the plane of the Skin
Actinic Keratosis
Hyperkeratosis
Common Skin Lesions
Above the plane of the Skin.
Callus
Corn
Common Skin Lesions
Above the plane of the Skin
papule
Nodule
Common Skin Lesions
Above the plane of the Skin
Wheal
Plaque
Common Skin Lesions
Above the plane of the Skin
Vesicle-
BlisterBulla-
Common Skin Lesions
Above the plane of the Skin
Pustule-
Cyst-
Common Skin Lesions
Above the plane of the Skin
Tumor:
Common Skin Lesions
Above the plane of the Skin
Verruca:
Common Skin Lesions
Above the plane of the Skin
Scale/crust
Desquamation
Common Skin Lesions
Above the plane of the Skin
Exudate
Common Skin Lesions
Above the plane of the Skin
Comedone
Common Skin Lesions
Below the plane of the Skin
Excoriation
Common Skin Lesions
Below the plane of the Skin
Ulcer
Common Skin Lesions
Below the plane of the Skin
Fissure
Common Skin Lesions
Below the plane of the Skin
Excoriation
Common Skin Lesions
Below the plane of the Skin
Eschar
Disorders of Pigmentation and
Melanocytes Blanched
Vitiligo
Disorders of Pigmentation and
Melanocytes
Albinism
Disorders of Pigmentation and
Melanocytes
Melasma
Disorders of Pigmentation and
Melanocytes
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Lentigo
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Due to melanocyte
proliferation.
Can be due to
hypermelanosis, Addison’s
disease, Hemochromatosis,
Acanthosis nigricans
Hydroquinone may temporarily
bleach the spots Inhibit
synthesis of pigment
Common Skin Lesions
Based on Color- Erythema
Erythema
Common Skin Lesions
Based on Color- Blue
Cyanosis
Common Skin Lesions
Based on Color- yellow
Jaundice
Approach to patient
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Distinguish normal vs. abnormal
Appropriate differential diagnosis
Pros and Cons of dermatology
Approach to the Patient
History-Lesions
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Acute vs. chronic illness
Onset
Subjective symptoms
Location, distribution, spread or change
in lesions
Approach to Patient
Physical Exam
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Observe four points:
Palpate
Systemic examination including
lymphadenopathy, organomegaly,
arthralgia, and neurological changes
Approach to Patient
Physical Exam
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Rash-
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Lesion-
Physical Exam
Shape of the Lesion
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Round
Oval
Polygonal
Annular
Serpiginous
Umbilicated
Physical Exam
Arrangement of lesions
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Grouped: herpetiform, arciform,
annulra, reticulated, linear,
Physical Exam
Arrangement of lesions
Disseminated-
Physical Exam
Arrangement of lesions
Demarcated
Discrete
Physical Exam
Arrangement of lesions
Diffuse-
Physical Exam
Distribution of lesions
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Extent:
Pattern:
Any characteristic patterns such as seen in acne, chicken
pox.
Special Signs and tests
Darier sign
Special Signs and tests
Auspitz Sign
Special Signs and tests
Nikolsky sign
Special Signs and tests
Diascopy
Diascopy•Blanching indicates intact
capillaries known as erythema.
•If no blanching capillaries are
not intact, known as purpura.
Special Signs and tests
Koebner phenomenon
Diagnostic Techniques
Wood Light Exam
Hair: green fluorescence in
tinea capitis
Skin: erythrasma: coral red
fluorescence
Hypomelanosis; decrease in
intensity
Diagnostic Techniques
Acetowhitening
Acetowhitening-
Diagnostic Techniques
Patch test
Diagnostic Techniques
Microscopic Examination
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KOH preparation
For bacteria: gram stain
For virus: Tzanck smear
For spirochetes:
Cultures: bacterial, viral,
parasitic, mycologic
Diagnostic techniques
Biopsy
Review 1
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Name the five layers of the epidermis
What enzyme is lacking in albinos? What does
this enzyme produce?
Which cells are known as touch receptors?
What is the function of the basement
membrane?
Which layer is composed of fat, connective
tissue and blood vessels?
Review 2
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List two types of sweat glands and state
their difference.
Describe a macule
What is Telangiectasia?
Describe lichenification
Describe a papule
Describe a nodule
Review 3
Describe this:
Review 4
What is this?
Review 5
What is this?
Review 6
What is this due to?
Review 7
What is this?
Review 8
What is this?
Review 9
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How would you
describe this lesion?
What is the
diagnosis?
Review 10
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Describe this lesion
What is your
diagnosis?
Review 11
What is this?
Review 12
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How would you
describe these
lesions?
Review 13
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How would
you
describe
this lesion?
Review 14
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What is this
sign? What does
it mean?
Review 15
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Filled with pus this is
known as:
Filled with fluid this is
known as:
If this is embedded in
the skin and filled with
fluid it is known as:
If it is solid it is known
as:
Review 16
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what sign is
positive?
Review 17
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What sign is
positive?
Review 18
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How would you
define these
markings?