APPROACH TO

DERMATOLOGICAL

DIAGNOSIS

DR. S.A.SHAH

FCPS, D.Dsc (UK),

M.A.A.C.S (USA)

Skin Lesions And Diagnosis

Thorough approach to the evaluation decreases the risk of

making an in correct diagnosis or overlooking another

diagnosis

Knowledge and appropriate use of dermatological

terminology are fundamental

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The entire mucocutaneous surface, as well as the hair and nails, should

be examined whenever reasonable.

Diseases have characteristics morphology and distribution.

Common pitfalls in dermatologic diagnosis exist and can be avoided.

Approach To The Patient

Introduction

History

History of present illness

Systemic review

Past medical & surgical history

Family history

Social history

Drug history

•Examination- cutaneous

- General physical

- Loco-regional

- Systemic

Differential diagnosis

Provisional diagnosis

Investigations

Final diagnosis

Treatment

Follow up

HISTORY

Dermatology a visual specialty

But In most cases, a carefully directed history is important

for :

- refining the diagnosis,

-for identifying further investigations

-and to address issues that may be important for optimal

management

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Perform a brief examination initially before taking history

it helps to obtain streamlined and more focused history

later

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Demographics

Name , Age, race, sex, occupation, residence , mode

of admission etc

Presenting complaint:

Symptoms.

Itch is the prime dermatological symptom

Rash

History of a growth

Symptoms usually parallel development of eruption but discordance can be diagnostically useful

History of present illness:

It includes complete detail of presenting

complaint.

History of a rash: key

questions

When did it start?

Did it itch, burn or hurt?

Where on the body, did it start?

How has it spread?

How have individual lesions changed?

Provocative factors?

Previous treatments & response?

History of a growth: key questions

How long has the lesion been present?

Has it changed, grown, bleed, itched or failed to heal?

Systemic review

Review of systems as indicated by

clinical situation, with particular attention to symptoms indicating a

possible connection between cutaneous signs

and disease of other organ systems.

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e.g. rheumatic complaints: myalgias, arthralgias, Reynaud's

phenomenon,

sicca symptoms.

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Review of symptoms for growth suspicious for,

or associated with malignancy.

Particular attention to symptoms of metastasis

(weight loss, fever, headache ,abdominal pain,

bone pain etc.)

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Constitutional symptoms

“Acute illness” syndrome: headaches, chills,

fever, weakness

“Chronic illness” syndrome: fatigue, weakness,

anorexia, weight loss, malaise

3. Past history

Illnesses

Operations

Atopic history

( asthma, hay fever, eczema)

4. Family history

Family medical history , particularly of skin disorders and of atopy.

Family history of skin and other cancers.

5. social history

Social history with particular reference

to occupation, hobbies , sun exposure, tobacco smoking, alcohol use,

recreational drugs , travel, sexual orientation and exposure.

6. Drug history

History of any drug intake.

History of drug allergies.

LABORATORY STUDIES

Special procedures as determined by individual

clinical situation:

Dermatoscopy

Hand lens

Biopsy for histopathologic & other analysis (electron

microscopy, immunofluorescence, special stains)

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Gram stain of scales , crust or exudates

Potassium hydroxide preparation for yeast or fungi

Tissues to be minced for bacterial and fungal culture

Cytological preparation (tzanck smear) in vesicular &

bullous eruptions

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Swab for bacterial, fungal, viral culture

Wood’s lamp examination of urine

for porphyrins & of hair & skin for fluorescence or for

changes in

pigmentation

Patch testing for allergic contact dermatitis

General laboratory studies

Hematology

Chemistry

Urine analysis

Serology

Imaging studies

Final diagnosis

Re-examination over time

More than one biopsy may be required for definitive diagnosis

Examination of the

dermatologic patient

Scope of the complete cutaneous examination:

it includes examining entire skin

Identification of potentially harmful lesions

Identification of benign lesion

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Finding hidden clues to diagnosis

(e.g. scabies lesions on penis,

psoriatic plaques on buttocks,

Wickham striae of lichen planus

on buccal mucosa.)

The pre-requisite of dermatologic diagnosis is recognition of

the type of skin lesion

the color

margins

Consistency

shape

arrangement

distribution of lesions

Recommended tools for skin examination

A magnifying tool such as loupe, magnifying glass,

dermatoscope.

A bright focused light

Glass slides

Alcohol pads to remove scales or surface oil

Gauze pads or tissues with water

Gloves

A Ruler for measuring lesions

A surgical blades for scraping or incising lesion

Camera for photographic documentation

A wood’s lamp for highlighting pigmentary changes

Techniques for dermatologic physical

examination

Inspection :

Observe the patient at a distance for any kind of

asymmetry , obesity, pallor, fatigue , jaundice.

Next examine the patient in a systematic way

from head to toe.

Palpation:

Palpate the patient for any kind of mass ,

growth,

whether they are soft ,fleshy, firm, tender

fluid-filled.

Palpation:

Palpate the lesion for ,

Texture

Consistency

Thickness

Tenderness

temperature

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After completing the examination ,

it is important to document the

findings