Dermatology Slides - Introduction to Clinical Dermatology

7/29/2019 Dermatology Slides - Introduction to Clinical Dermatology

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Dermatology Slides

Introduction to clinical

dermatology

Hiba Jarra7

25


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2 layers: Epidermis and Dermis Epidermis: All Cells (keratinocytes 85%,

MC,MC,LC):

4-Cell layers (Keratinocytes):1. Basal layer:

2. Prickle(spinous,squamous) layer:

3. Granular layer

4. Horney layer:


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Cells travel frombasal layer towardssurface (Turnover)

The trip takesaround 60 daysthen cells are shedfrom surface.

Shed cells arereplaced from basalcells (mitosis).


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Melanocytes: Dendretic Derived from neural crest

Within Basal layer

Produce melanin which is then transferred to KC

Langerhans cells: Dendretic Skin tissue macrophages

APC of both epidermis and dermis

Present throughout epidermis

Merkel cells: non-Dendretic Transducers for fine touch

At Basal layer


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Dermis several components:1. Fibers: collagen and elastic fibers

2. Ground substance (GAGs)

3. Cells: Fibroblasts, Lymphocytes, Macro,

Mast cells..

4. Appendages: Glands ( sebaceous, Apocrineand Eccrine), Hair follicles and Nails

5. Supportive structures: Nerves, lymphatics,vasculature, smooth muscles


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The main function of skin to prevent entry offoreign things into internal environment

Horney layeris the main structure

responsible for this

Problems and diseases affecting Horney layerwill impair this function leading to infections,allergies


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Always start by introducing yourself

Ask patient permission before examining

them

Always respect patient wishes

Always keep patient privacy


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Chief complaint + Duration: Rash: multiple red things with/out scale

Lesion: one or few things

Others: as appropriate ( e.g hair loss, blisters, colorchange)


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Analysis of the complaint : Onset and progression: site where it started and

how, increasing/decreasing/same , and which sites

Modifying factors?

Symptoms: itch, pain

Recent illness: viral/fevers.. (esp for rashes)

Atopy: asthma+eczema+hay fever (personal or 1stdegree relative)

Drugs used ?


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R.O.S: Related Past Hx: as per others

Family hx


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T. SAD: Type: primary vs secondary (modified..scratched,

traumatized) lesion

Macule/patch: pigmentary disorder or resolvingpapulosq

Scaly papules/plaques: papulosquamous condition

Non scaly papules/plaques: reactive erythema

Bullae/vesicles: bullous dis.


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Shape: details of the primary lesion Color:

red: more RBC.s(Hb) eithre intravascular(dilated vessels)or extravascular (hemorrhage)

Brown/black: melanin

Yellow: carotene (Horney layer and sc fat)

Exogenous.

Surface: Scaly: papulosqumaous

Non scaly.

Margins: well defined vs ill-defined (esp important forscaly rashes)


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Arrangement: Grouped: grouped vesicles (Herpes), Linear ( plane

warts, Kobner)

Distribution: where? Unilateral: infection, contact Bilateral: inflammatory

Hands/face: sun exposed(photodermatoses/photoaggravated dermatoses).


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Approach ??


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Red is BLOOD

This is eitherIntra vascular: dilated vessel due to usually release

of inflammatory mediators (histamine)

DIASCOPY.BLANCHABLEExtra vascular: Hemorrhage

- Vessel wall injury: vasculitis

- Bleeding tendency or due to trauma

- DIASCOPY.NON-BLANCHABLE


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Red NON-

Scaly rash

DIASCOPY

NON-

Blanchable

VasculitisBleeding

tendency

Blanchable

Reactive

Erythema

(Urticaria/E

M/EN)


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Red non scaly

(ask about Duration

Of individual lesion)

UrticariaTime limit for

Individual wheals

Of 24 hrs

Erythema multiformeLesions for 1-2 wks

Acrofacial dist

Target lesions

Erythema nodosum

Lesions last 4-6 wks

Shins

Painful hot tender

Nodules.

Bruise like upon

resolution


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Scale is flake (piece) from horney layer.

Usually indicates hyper-proliferation ofepidermis

The group includes many conditions butcommonest are:- Eczema - Lichen Planus- Psoriasis - Fungal infections

-Pityriasis Rosea


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Look forspecial

features

Next: look at

distribution:

Look at

margins:Scaly rash

Well-defined

margins

Unilateral:Fungal infection

Bilateral:-psoriasis

-P.Rosea

- Lichen Planus

Ill-defined

margins

Eczema


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Scaly,well defined,

Bilateral

Psoriasis

CommonestSalmon pink

Large silvery scales

Extensor dist

Lichen planusViolaceous color

Wickhams striae

Flexors

Pityriasis Rosea

Time limit 2-10 wksMother plaque

Trunk dist (christmas

Tree/ribs)


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Solid,elevatedwithoutdepth

Bilateral

6 monthsduration


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5 monthsduration,elevated, no

depth, finescales.


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1. Woods light2. KOH

3. Diascopy

4.

Tzanck smear5. IF (Direct: tissue and Indirect: plasma)

6. Patch Test


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The End!!!!

Documents

Dermatology Slides - Introduction to Clinical Dermatology