INTRODUCTION TO
DERMATOLOGY
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Dermatology deals with disorders of skin, hair,
nails, and mucous membranes.
Important functions of the skin
Protection against external injury
Fluid balance
Temperature organ
Synthesis of Vit D
Part of immune system (e.g. langerhan’s cell)
Cosmetic function.
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•Dermatological disorder = 10% -15% of
primary care consultations
•Skin is the largest organ in human body
•Dermatological diseases can cause
social and psychological problems, also it
may affect ability to work (e.g.. Chronic
hand dermatitis.)
•Skin is the gate of the body(might reflect
systemic disease).
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Structure of skin
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Epidermis
Basement membrane (dermoepidermal junction)
Dermis
Subcutaneous fat
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1.
2.
3.
4.
Epidermis: Four layers (from outside – inside)
Cornified layer
Granular layer
Spinous layer
Basal layer

Dermis contains:
Collagen fibers
Elastic fibers
Ground substances
Blood vessels
Nerves.
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Skin appendages:
Hair follicle
Sebaceous gland
Arrector pili muscle
Eccrine sweat gland
Apocrine sweat glands
Nail
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Dermatological History
 age, sex
Chief complaint : + duration
itching
burning
pain
 History of present illness
When and how started?
Mild, moderate or severe?
Aggravating or reliving factors?
Any other symptoms
Review of systems
Past medical history
Drug history
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Occupation
Hobbies
Travel
Family history
Examination:
3 corners to make useful skin exam
1. Morphology (shape of the lesion)
2. Configuration (arrangement of lesions)
3. Distribution (Which body site)
Morphology:
1º skin lesions : unmodified lesions
2º skin lesion: modified by scratching or infection
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Primary Lesions
Macule
Papule
Plaque
Nodule
Cyst
Wheal
Vesicle
Bulla
Purpura
Burrow
Telangectasia
Secondary lesions
Crust
Erosion
Scale
Ulceration
Excoriation
Scar
Atrophy
Fissure
Necrosis
Lichenification
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Primary skin lesions
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Macule & patch
• A macule is a
circumscribed flat
alteration in the colour of
the skin which is less
than 1 cm in diameter.
• Various colors depending
on the cause
• A patch is a flat lesion
greater than 1 cm in
diameter (i.e. a large
macule).
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Papule
• A papule is a circumscribed palpable elevation
of the skin less than 1 cm in diameter
• Dermal(drug eruption, lipid deposits), epidermal
(warts, molluscum), or both (lichen planus)
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Nodule
Palpable solid deep lesion (depth> diameter)
- Epidermal
- Dermal
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Plaque
• A slightly raised lesion
greater than 1 cm in
diameter
• Papules confluence
(psoriasis)
• Patch thickening
(mycosis fungoides)
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Vesicle
• A raised lesion less
than 0.5 cm in
diameter containing
clear fluid
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Bulla
• A vesicle that is
greater than 0.5 cm in
diameter is known as
a bulla.
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Pustule
• A pustule is a raised
lesion less than 0.5
cm in diameter
containing yellow
fluid, which may be
sterile as in acne or
pustular psoriasis, or
infected.
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Wheal
• A wheal is a transient,
itchy, pink or red
swelling of the skin,
often with central
pallor.
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Cyst:
palpable soft sac
containing fluid.
- Epidermal
- Dermal
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Telangiectasia
• Dilatation of capillaries gives rise to this skin
condition.
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Secondary skin lesions
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Crust
• A crust is a dried
exudate, which may
have been serous,
purulent or
haemorrhagic.
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Excoriation
• A haemorrhagic
excavation of the skin
resulting from
scratching.
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Lichenification
• Thickening of the skin
with exaggeration of
the skin creases.
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Scar
• The final stage of healing of a destructive
process (disease or injury) that has involved the
deeper dermis results in a white, smooth, firm,
shiny lesion.
• Atrophic, or hypertrophic
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Scale
• A scale is a flat plate (lamella) or flake of stratum
corneum.
• The epidermis is replaced every 28 days
• Fine (eczema) / thick (psoriasis)
• No scaling in dermal pathologies
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Poikiloderma
• This refers to an
appearance of
pigmentation, atrophy
and telangiectasia
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Necrosis
• Death, or necrosis, of
skin tissue is usually
black in colour.
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Erosion
• A partial break in the
epidermis is known
as an erosion
• It heals without
scarring unless
secondary infection
occurs.
• Commonly following a
blister
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Ulcer
• An ulcer is a fullthickness loss of the
epidermis
• Heals with scarring
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FISSURE
a linear cleavages or
cracks in the skin.
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Atrophy
• Thinning and
transparency of the
skin
• Caused by diminution
of the epidermis, the
dermis, or both
• Wrinkling and
translucency
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Sclerosis
• A circumscribed or diffuse hardening or
induration of the skin
• A result of dermal or subcutaneous edema,
cellular infiltration, or collagen proliferation
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Primary Lesions
•Macule: Flat circumscribed area of change in skin
color
•Papule: small circumscribed elevation of the skin
•Nodule:Solid, circumscribed elevation of the skin
whose greater part is beneath skin surface (felt more
than seen)
•Plaque: flat topped palpable lesion (gathering of
papules)
•Vesicle: collection of clear fluid (<5mm in diameter)
•Bulla: like vesicle, but > 5 mm
•Pustule: Collection of Pus
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Primary Lesions
* Wheal: Transient, slightly raised lesion
with pale center and pink margin.Seen in
urticaria.
* Purpura:Visible collection of blood
under the skin e.g. Vasculitis
* Telangectasia: Dilated capillaries
visible on skin surface
* Burrow: Tunnel in the skin (e.g.
Scabies)
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Secondary lesions
•Crust: Dried serum (or exudate)
•Scale:Thickened, loose, readily detached fragment of
cornified layer
•Excoration: Shallow linear abrasion caused by
scratching.
• Erosion:Loss of epidermis (heals without scarring)
•Ulcer: loss of epidermis and dermis (heals with
scarring)
• Fissure : linear crack in the skin
•Scar: Permanent lesion due to abnormal formation of
connective tissue following injury.
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Secondary lesions
Atrophy: A-Superficial: thining of skin
with visible blood vessels
B-Deep : depression of skin
surface
Lichenification: thickened skin with
accentuated skin
markings
Sclerosis: induration of skin
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Distribution
Predilection for specific body sites
*Psoriasis: Extensors(elbows and knees)
Scalp
*Acne:Face
Upper chest, Upper back
*Photosensitive eruption: Mainly face, forearms
& V-Chest (with sparing of photoprotected
areas e.g. upper eyelids, retro-auricular an submental)
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Colour in Dermatology
Red:Vascular lesions e.g. port wine stain
also, inflammatory disorders like psoriasis
Blue:
Blue nevus
Mongolian spot
Yellow: Xanthoma
White: Vitiligo
Black:
Melanocytic nevus & melanoma
Purple or (Violaceous) : Lichen planus
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Some important signs in Dermatology
*Auspitz sign: When you remove a scale
from psoriasis lesion  tiny bleeding
points (due to suprapapillary thinning).
Nikolsky sign: When you rub normal
skin beside blister  induction of new
blister .Seen in pemphigus vulgaris and
toxic epidermal necrolysis(TEN).
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Nikolsky sign
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Dermatographism: When you stroke the
normal skin  edema and erythema (you can
write on skin!) .Seen in physical urticaria
Kobener Phenomenon: Induction of new
skin lesions on previously normal appearing
skin by truma e.g. in psoriasis, wart, lichen
planus
Button-hole sign: In neurofirbroma, if you try
to push it  it goes inside the skin
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Additional skin examination:
~Wood’s Lamp: Produces long wave ultraviolet
light(UVA). e.g.
Vitiligo  milky white
Tinea Versicolor  golden
Tinea Capitis (caused by microsporum)  yellow
green
Erytherasma  coral red
~Diascopy:you press with a glass slide .
If there is red lesion and the redness dose not go away
by this pressure  this means extravasated blood
i.e.purpura
~Dermatoscopy: Helpful to differentiate benign from
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malignant pigmented lesions.
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Investigations:
*KOH and fungal culture
•Scrap skin scales  put over
glass slide
•Add KOH 10% -- warm gently
•See under microscope
•You may see hyphae and/ or
spores
*Gram stain and bacterial
culture
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Investigations:
Tzank smear: Scrap base of
vesicle smear it on microscopic
slide  add fixative  add
Giemsa stain.
Examine under microscope for
1.Detached epidermal cells
(acantholytic cells) in pemphigus
vulgaris
2.Multinucleated giant cells in
herpes simplex, zoster or varicella
 Viral culture
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Skin biopsy : Under local anasthesia, different types:
Punch
Shave
Excisional
Incisional
Immunofloursence :
important in immunobullous disorder
1.
Direct : use pt’s skin
2.
Indirect: use pt’s Serum
Prick test
Patch test
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Treatment:
Topical corticosteroids
Mechanism of action
1. Anti-inflammatory
2. Anti-proliferative
3. Vascoconstrive
4. Immunosuppressive
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Topical steroids (cont’d)
7 Categories, according to strength .
Category one is superpotent (used only on
chronic cases or resistant disorder on thick
skin) .Not used on face or in children. e.g.
Dermovate (clobetasol propianate).
Category seven is very mild: can be used
safely in children or over face, also for longer
periods of treatment
See tables.
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Group 1 (Most Potent)
Clobetasol propionate ointment 0.05% (Temovate,Dermovate)
Clobetasol propionate cream 0.05% (Temovate, Dermovate)
Betamethasone dipropionate ointment 0.05% (Diprolene)
Group 2
Betamethasone dipropionate cream 0.05% (Diprolene)
Mometasone furoate ointment 0.1% (Elocom)
Group 3
Fluticasone propionate 0.005% (Cutivate)
Group 4
Mometasone furoate cream 0.1% (Elocom)
Triamcinolone acetonide ointment 0.1% (Kenalog)
Hydrocortisone valerate cream 0.2% (Westcort)
Hydrocortisone butyrate ointment 0.1%(Locoid)
Group 5
Fluticasone propionate cream 0.05% (Cutivate)
Triamcinolone acetonide 0.1% (Kenalog)
Hydrocortisone valerate cream 0.2% (Westcort)
Hydrocortisone butyrate cream 0.1%(Locoid)
Group 6
Alclometasone dipropionate 0.05% ointment (Perderm)
Alclometasone dipropionate 0.05% cream (Perderm)
Group 7
Topical preparations with hydrocortisone acetate 1%
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Topical steroids (cont’d)
Various formulations:
Ointment, cream ,gel, solution, lotion
Side effects (if used for long period and at
inappropriate site):
Atrophy , Acne
Telangectasia, Hypertrichosis
Folliculitis, Hypopigmentation
If large amounts  systemic absorption .
But if you use it with appropriate strenght and
amount in appropriate site; these S/E are
unlikely to happen
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•Topical Antifungal :
–Miconazole
–Terbinafine
–Clotrimazole
–Ketoconazole
etc….
•Topical Antibiotids:
–Fusidic acid
–Mupirocin
–Erytheromycin
–Clindamycin etc…
•Topical retinoids (vit.A derivatives)
–Commonly used In Acne
–e.g. Treitinoin(Retin A)
Adapalene(Differin)
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*Topical vit. D analogues
calcipotriene (daivonex).Used in psoriasis
Main S/E :hypercalcaemia
if more than 90 grams used per week (for adult)
*Topical chemotherapy:e.g. 5 -flurouracial, used for
actinic keratosis (premalignant skin lesions)
*Topical immunomodulator :e.g.
-Imiquimod(Aldara )used for genital warts
*Topical immunosuppersives: e.g.
-Tacrolimus used for Atopic Dermatitis
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Intralesional treatment
*IL steriods : e.g. Triamcenolone acetonide
(kenalog) with different concentration according
to the case
Used in many skin disease e.g.
Alopecia areata (localized vaiant)
Keloids
Licen simplex chronicus
Hemanigomas
S/E: atrophy
hypopigmentation.
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I L chemotherapy:
*Bleomycin : for plantar warts
*Vinerstine and vinblastine: for kaposi
sarcoma
IL Antiprotoza:
like Na stibogluconate used in treatment
of leishmaniasis
Intramuscular injections:
*Steriods
*Pentostam (Na stibogluconate)
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Physical methods
-Cryotherapy : e.g. Liquid Nitrogen used
in treatment of warts
-Electrcautery
-Sclerotherapy for varicose viens
-Curettage
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Oral Medications
Systemic steroids:
The most commonly used is prednisolone
What are the S/E ?
DM ,Wt gain
HTN
HPA axis suppersion
Osteoprosis,
Avascular necrosis
Pyschosis,Depression
etc….
How to prevents them?
Monitor BP, blood sugar
Vit. D. ,Calcium supplement
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Oral Medications
Antibiotics:
Pencillins
Cephalosporins
Macrolides
Fluoroquinolones
Tetracyclines
Anti-TB
Anti- Leprosy
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Oral Medications
• Antifungal : e.g.
Terbinafine
Itraconazole
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Griseolfulvin
Ketoconazole
Antiviral
Acyclovir
Famcilovir
Valacyclovir
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Oral Medications
*Immunosuppressive and antiproliferative
Azathiopurine (imuran)
Cyclosporin-A
Mycophenolate Mofetil
Cyclophosamide
Methotrexate
*Antimalaria
* Interferones
*Systemic Retinoids
e.g. Isotreitonoin, used in acne
Acitertin used in psoriasis
S/E?(elevate LFT and Lipids,also Teratogenic)
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Oral Medications
Antihistamine:for itching
-sedating(e.g.Hydroxyzine,Chlorphenarmine)
-non sedating(e.g Loratidine and Cetrizine)
Antiandrogens
Psychotropic
Colchicine
Potassium iodide
Emoillents
Sunscreen: Chemical and physical
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Phototherapy
Ultraviolet light A or B
with or without psoralen
PUVA (psoralen + UVA)
New modalities:
Narrow band UVB
UVA – 1
Excimer laser(308nm)
Indications: psoriasis, vitiligo, atopic
dermatitis,CTCL(cutaneous T cell
lymphoma )etc…
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Laser
acronym for:
Light
Amplification
Stimulated
Emission
Radiation
Harmful if accidently goes to the eye.
Does not induce cancer
Safe for pregnant ladies
Different wavelengths targeting different chromophores
Types: Vascular , Pigmentary
Resurfacing, Hair removal
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Laser Tissue Interactions
Depth of Penetration
Er
C02
KTP
PD
Ruby Alex
Nd YAG
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Thank you
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