principle of dermatology

8/13/2019 Principle of Dermatology

1/49

PRINCIPLE OFDERMATOLOGY

By : dr. Nanda Earlia, Sp.KK


2/49

Introduction

Key point1. Many out patien visits are for dermatologic

complaints2. The patienss chief complaint can be devided

into two diagnostic skin disease: growths andrashes


3/49

Structure & Function of skin

Key Points1. The major function of the skin is as a barrier

to maintain internal homeostasis2. The epidermis s major barrier of the skin


4/49

Component of the skin

EpidermisDermisSkin appendagesSubcutaneous fat


5/49

Epidermis

Key point

1. Layer in ascending order: Basal cell, stratum spinosum, stratumgranulosum, statum corneum

2. Basal cells are undifferentiated, proliferating cells

3. Stratum spinosum contains keratinocytes connected by desmosomes4. Keratohyalin granules are seen in stratum granulosum

5. Stratum corneum is major physical barrier

6. The number and size of melanosomes, not melanocytes, determine skincolor

7. Langerhans cells are derived from bone marrow and are the skins firstline immunologic defense

8. The basement membrane zone is substrate for attachment of epidermis tothe dermis

9. The four major ultrastructural regions include the hemidesmosomal plaque

of the basal keratinocyte, lamina lucida, lamina densa, and anchoringfibrils located in the sublamina densa the region of the papillary dermis.


6/49

Cell division occurs in the basalcell layer


7/49

Skin function

Function Responsible structure

Barrier:PhysicalLightImmunologic

EpidermisStratum corneumMelanocytesLangerhans cells

Though flexible foundation DermisTemperature regulation Blood vessels

Eccrine sweat glands

Sensation Nerves

Grasp Nails

Decorative Hair

Unknown Sebaceous glands

Insulation form cold andtrauma

Subcutaneous fat

Calorie reservoir Subcutaneous fat


8/49

Structure

Keratization begins in stratumspinosum

Granular cells contain keratohyalinlamellar granularThe stratum corneum is the majorphysical barrierLangerhans cells are the first line of

immunologic defense in the skin


9/49

Dermis

Keypoint1. Provides structural intregity and is biologically

and active2. The primary components of the dermal matrix

are collagen, elastin, and extrafibliar matrix


10/49

Structural components of thedermis

ColagenElastic fibersExtrafibliar matrix

Free nerve endings are the mostimportant sensory receptors


11/49

Functions of blood vessels:

To supply nutritionTo regulate tempearture


12/49

Skin appendages

Key point1. Eccrine glands help to regulate body

temperature2. Apocrien sweat glands depend on androgen

for their development3. The stem cells of the hair follicle reconstitute

the nonpermanent portion of the cycling hairfollicle

4. Sebaceous glands are under androgencontrol


13/49


14/49

Types of hair

Vellus (light and fine)Terminal (dark and thick)

Hair growth cycles through (anergen),transitional (catagen), and resting

(telogen) phases.Normally, 25 to 100 hairs are shed from thescalp each day


15/49

Sebaceous glands

Sebaceous glands are androgen dependent


16/49

Nails

Nail is made of keratin produced in the matrix


17/49

Subcutaneus fat

1. Insulates2. Absorbs trauma

3. Is a reserve energy source


18/49

Principle of diagnosis

HistoryPhysical examination

Terminology of skins lessionClinicopathologic of skins lesionsConfiguration of skin lesions

Distribution of skin lesions


19/49

Key points1. Morphologic appearance is critical in

making the diagnosis2. Skin diseases can be divided into

growths and rashes


20/49

Steps in dermatologic diagnosis

HistoryPhysical- identify the morphology of basiclesionConsider Clinicopathologic correlationsConfiguration of distribution of lesions (whenapplicable)

Laboratory testDermatologic diagnosis depends on the examiners skill

in skin inspection


21/49

History

Key pointsLet the patient talk uninterruptedly in thebeginningClarify duration, symptoms, distribution,and treatmentExpand the history based on thedifferential diagnosis


22/49


23/49

Follow up History

For persistent skin infections,consider the possibility of AIDS.

A complete skin exposure history isrequired whenever contact dermatitisis suspected


24/49

Physical examination

Key pointsComplete skin examination is recommendedat the first visitGood lighting is criticalDescribe the morphology of the eruption


25/49

The entire skin surface isexamined for

Lesion that may accompany the presentingcomplaintUnrelated but important incidental findings

Side sighting helps to detect subtle elevations

he scalp, mouthm and nails should not be overloa


26/49

Palpation helps to:

1. Assess texture and consistency2. Evaluate tenderness3. Reassure patients that they are not

contagious

The most important task in the physical examination is toCharacterize the morphology of the basic lesion


27/49

Terminology of skin lesion

Key pointsPrimary lesion include muscle, patch, papule,plaque, nodule, cyste, vesicle, pustule, ulcer,wheal, telangiectasia, burrow, and comedoSecondary lesion include scale, crust, oozing,lichenification, induration, fissure and atrophy


28/49

Clinicopathologic corellation

Key points.Envisioning the gross and microscopicmorphology together helps to make thediagnosisRash or growth ?Epidermal, dermal, or subcutaneous ?

etermine which of the skin components are involved in clinical lesio

Growth are hyperplastic lesions; rashes are inflamatory


29/49

Clinicopathologic corellation

Skin component Pathologic alteration Clinical manifestation

EpidermisStratum corneum Hyperkeratosis Scale

Subcorneal epedermis Hyperplasia

HyperplasiaDisruptive inflammatorychangesDried serum

Lichenification

Papules, plaques andnoduleVesicle, bullae and pustulecrsust

Dermis

Blood vessels Hyperplasia or inflammationVasodilatationHemorrhageVasodilatation with edema

Macule, papules,andnodulesErythemaPurpurawheals

Nerves Hyperplasia Papules, nodules


30/49

Clinicopathologic corellation (Part2)

Skin component Pathologic alteration Clinical manifestation

Connective tissue HyperplasiaLoss of epidermis anddermis

Induration, papules, nodules,and plaques ulceration

DermalappendagesPilosebaceousunits

Hyperplasia AtrophyHyperplasia orinflammation

Hirsutism AlopeciaComedones, papules, nodulesand cyst

Sweat glands HypersecrationHyperplasia orinflammation

HyperhidrosisVesicle, papules, pustules andcyst

Subcutaneous fat Hyperplasia orinflammation

Induration and nodules


31/49

Schematic for diagnosis of skindiseases


32/49


RashesWith

epidermalinvolvement

Eczematous

Scaling

vesicluar

papular

pustular

papular

Hypopigmented


33/49


RashesWithout

epidermalinvolvement

Blanchable Eritema

Genneralized

Localized

Speciallized

notblanchable Purpura Macular

papular

Indurated


34/49


Miscellaneous

Epidermal

Hair disorder

Nail disorder

Mucous membrane disorder


35/49

Growths

Growth are subdivided into one threecategories

1. Epidermal2. Pigmented3. Derma or subcutaneousScale and hyperkeratosis are both terms forexcess stratum corneumMalignant epidermal growths usually feelindurated

A skin biopsy is often required for diagnosis ofa dermal nodule


36/49

Rashes

Licheification is the hallmark of chroniceczematous dermatitis

Epidermal rashes:1. Eczematous2. Scaling3. Vesicular

4. Papular5. Pustular6. Hypopigmented

Scale must be distinguished from crust


37/49

Vesicle and bullae are important anddiagnostic findings

Pustules often (but always) indicatesinfectionHypopigmentary changes areaccentuated with woods lightexamination


38/49

Macular purpura is usually a signof bleeding disorder ; papular

purpura indicates a necrotizing

vasculitis, often systemic


39/49

Miscellaneous conditions

Chronic skin ulcers should be undergobiopsy to rule out malignancyFor alopecia, first determine whether it isscarring or non scarring.


40/49

Configuration of skin lesion

Key points1. Configuration cal help make the

diagnosis2. Morphology is more important than

configuration

S l f


41/49

Some examples ofconfiguration

Configuration Morphology Diseases

Linear VesiclesPapules

Contact dermatitisPsoriasisLichen planusFlat warts

Grouped VesiclesPapules

Herpes (Simplex & Zoster)Insect bites

Annular Scaling

Dermal plaque

Tinea corporisSecondary syphilisSubacute cutaneous lupuserythematosusGranuloma annulare

geographic WhealsPlaques

UrticariaMycosis fungoides


42/49

Mucous membrane disorder

Erosions and ulcerationsWhite lesions


43/49

Distribution of skin lesions

Key points1. The distribution of skin lesion and the region

affected can help to suggest or confirm a

diagnosis


44/49

REGIONAL DIAGNOSE


45/49

Growth Rashes

Scalp

Nevus Seborrheic dermtitis (dandruff)

Seborrheic keratosis PsoriasisPilar cyst Tinea

Folliculitis

Face

Nevus Acne

Lentigo Acne rosasea

Actinic keratosis Seborrheic dermatitis

Seborrheic keratosis Contact dermatitis (cosmetics)

Sebaceous hyperplasia Herpes simplex

Basal cell carcinoma Impetigo

Squamous cell carcinoma Pityriasis alba

Flat ward Atopic dermatitis

Nevus flammeus Lupus erythematosus


46/49

Growth Rashes

Trunk

Nevus Acne

Skin tag Tinea versicolorCherry carcinoma Psoriasis

Seborrheic keratosis Pityrisis rosea

Epidermal inclusion cyst Scabies

Lipoma Drug eruption

Basal cell carcinoma Vricella

Keloid Mycosis fungoides

neurofibroma Secondary syphillis

Genitalia

Wart (condyloma acuminata) Herpes simplex

Molluscum contagiosum Scabies

Seborrheic keratosis Psoriasis

Lichen planus

Syphillis (chncre)


47/49

Growth Rashes

Groin (inguinal)

Skin tag Intertrigo

Wart Tinea crurisMolluscum contagiosum Candidiasis

Pediculosis pubis

Hidradenitis suppurtiva

Psoriasis

Seborrheic dermatitis

Extremities

Nevus Atopic dermatitis

Dermatofibroma Contact dermatitis

Wart PsoriasisSeborrheic keratosis Insect bites

Actinic keratosis Erythema multiform

xanthoma Lichen planus (wrists and angkles)


48/49

Growth Rashes

Extremities

Actinic purpura (arms)

Stasis dermatitis (legs)Vasculitis (legs)

Erythema nodosum (legs)

Hands (Palmar)

wart Nonspecific dermatitis

Atopic dermatitis

Psoriasis

Tinea manuum

Erythema multiform

Secondary syphillis


49/49

Growth Rashes

Feet (dorsal)

Wart Contact dermatitis (shoe)

Feet (plantar)Wart (plantar) Contact dermatitis (shoe)

Corn Tinea pedis

Nevus Nonspecific dermatitis

Psoriasis

Atopic dermatitis

principle of dermatology

Documents