Prof. DOULAT RAI BAJAJ
FCPS, MCPS
Professor & Chairman
Dept. of Dermatology
LUMHS
How to Diagnose Skin
Disease

History

Examination

Investigations
History
Presenting Complaints
 History of Presenting Complaints
 Past History
 Travel History**
 Drug History**
 Family history
 Personal History
 Socioeconomic history etc
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HISTORY of Presenting Illness
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Duration: When did it start?
Onset: sudden or gradual: varicella, P.Rosea
Does it itch, burn or hurt?
Where on the body it did it start?
Progress: How it spread on body; pattern of
spread
What changes have occurred?(evolution of lesions)
Aggravating/Relieving factors
Previous treatments; its effect on lesions
How to Diagnose a skin Disease

Evolution of lesions

How the lesion started?

What were initial signs?
For Example:
1. Viral lesions start as erythematous papules &
evolve into vesicles.
2. Porphyria cutanea tarda presents as vesicles on
hands progressing to scars.
3. Cutaneous T cell lymphoma starts as itchy
eczematous plaques  papules and nodules
How to Diagnose a skin Disease
Symptoms

Pruritus is an important symptom of:
Atopic dermatitis
Allergic contact dermatitis
Biliary cirrhosis
Cutaneous fungal infections
 Cutaneous lymphomas
Ch.Liver/Renal disease
Scabies
How to Diagnose a skin Disease

Pruritus is typically NOT present in:
 Secondary syphilis
Leprosy
How to Diagnose a skin Disease

PAIN :
Skin diseases in which pain is an Important symptom:
1. Acute viral infections
2. Leiomyoma
3. Acute vasculitic lesions
4. Neurofibromas
5. Glomus tumour
Travel History
 Travel
to endemic areas:
– Leishmaniasis
– Guinea worm
– Trypanosomiasis
Drug History

Sulphonamides: Many types
 NSAIDs: SJS syndrome, psoriasis, TEN, urticaria
 B-blockers: psoriasis, LE
 ACEIs: Psoriasis, urticaria, angioedema
 Diuretics: xerosis, photosensitivity
 Minocycline: SLE, pigmentation
 Chloroquin: bleaching of hair
 Laxatives: FDE
 ATT: LP
Personal History/Job/hobbies

ACD: Cement, fertilizers, domestic chemicals,
water, farmers etc
 Dentists: herpetic whitlow
 Fish Tank granuloma: pond workers, fish fanciers
 Sporotricosis and other deep fungal infections:
horticultural workers, gardeners, forest workers
 Photodevelopers: Lichenoid eruption
 Acne: oil workers, industry workers
 Radiologists, radiation workers: Skin carcinomas
Personal History contd……

Contact with animals pets:
–Ringworms
–Orf
–Erysipelas
–Histoplasmosis
Family History
Genodermatoses: neurofibromatosis,
TSC, XP
 Scabies, chickenpox, pediculosis

EXAMINATION
Note the following Features:

Site
 Distribution:
Generalized: psoriasis, LP, varicella, urticaria, drug
eruptions, AD
Localized:
Sebhorroic dermatitis: on sebhorroic areas
Scabies: genitals, finger webs, wrists, elbows, axillae
 FDE: lips, genitals
 DLE: Face, sun-exposed areas
PLE: Sun-exposed areas
Examination contd….
Morphology of lesions
 Type of lesion: Papules, macules, patches,
plaques, bulla, ulcers, erosions etc
 Size of lesion: Macule (freckles) vs patch (vitiligo)
Papule (warts) vs plaque (psoriasis)
Vesicle (viral) vs bullae (pemphigus)
Nodule (leprosy) vs tumous (BCC)
 Shape/configuration:
annular, discoid, arcuate,
polycyclic etc.
 Surface: smooth (keloid), rough (psoriasis)
keratotic (warts)
Examination contd
 Colour:
red (psoriasis, eczemas), skin coloured
(acne, warts, neurofibromas), violacous (LP), black
(tatoos, melanoma), slate gray (syphilis), pale
(PV), milky white (vitiligo), pink (P rosea)
 Consistency: solid (warts, LP), cystic (MC, Sebaceous
cyst), vesicular (viral), bullous (pemphigus, pemphigoid)

Margins: well demarcated (psoriasis, erysipelas),
poor demarcated (cellulitis, leprosy)
Examination contd….
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Pattern:
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Discrete: molluscum, warts, chickenpox
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Grouped: herpes simplex, plane warts, lichen nitidus,
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Segmental: vitiligo, nevi
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Dematomal: herpes zoster, vitiligo
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Bizarre: incontitia pigmenti, dermatitis artefacta
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Scattered: extensive: many types of eczemas
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Symmetry: Symmetrical (psorisis, AD, Discoid eczema),
Asymmetical( tinea, TB)
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Linear:
How to Diagnose a skin Disease
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Guttate psoriasis:
discrete lesions on
chest
How to Diagnose a skin Disease

Bizarre pattern: Verrucous epidermal nevus
linear
Occur due to involvement of
dermatome, blood vessels or
lymphatics.
 May be developmental origin.
 May follow Blashko’s lines.
 Koebner phenomenon.
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Examination contd…
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Shape/Configuration
– Annular (centre clear): Tinea, LP, psoriasis
– Discoid (centre filled) : discoid eczema,
psoriasis, UV
– Arcuate (incomplete circles): urticaria
– Serpiginous (snake): cutaneous larva migrans
– Reticulate: livido reticularis, cutis mormorata
– Polycyclic: psoriasis
– Target: EM
How to Diagnose a skin Disease
Arcuate
:An arc like or moon shaped
arrangement.
e.g. Stevens Jhonson syndrome
How to Diagnose a skin Disease
Arcuate lesions:
Stevens Johnson
Syndrome
How to Diagnose a skin Disease
 Satellite
 Candidiasis
 leishmaniasis
Lesions
How to Diagnose a skin Disease

Satellite lesions: candidiasis
How to Diagnose a skin Disease
Location/Site of lesion
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Psoriasis: Extensor areas, scalp & nails
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Vasculitis: Feet, lower limbs, buttocks
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E. Nodosum, P.gangrenosum: legs, thighs
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DLE: face, nose, pinnae, neck
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SLE: malar area of face, bridge of nose
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Herpes simplex: near muco-cutanous junction
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Herpes zoster: in zosteriform distribution
How to Diagnose a skin Disease
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Secondary syphilis: trunk, palms & soles
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Pityriasis versicolour: Trunk, back, arms
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Atopic dermatitis: cheeks, wrists, flexures
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Porphyria: face, dorsa of hands & feet
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Lichen Planus: wrists, lumbar regions, oral
mucosa
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Pemphigus Vulgaris: Head and upper trunk
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Adenoma sebaceum of TSC: around nose
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Stevens Johnson Synd: Acral parts and
mucosal surfaces
How to Diagnose a skin Disease
 Trans
 Carry
location of lesion
the lesion to its typical site in your
mind.
 This
concept is helpful when diseases
present on atypical sites.
Palpation of Lesions
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Simple palpation: to determine texture
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Blunt pressure: to detect oedema, capillary refill, identify
the dermal defect in anetoderma.
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Linear or shearing pressure: to elicit dermographism, or
Nikolsky’s sign in pemphigus
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Squeezing or pinching: to determine depth
& consistency of lesions: pinching in scleroderma,
squeezing dermatofibroma lesion produces dimpling
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Rubbing: release chemicals, e.g. rubbing a mastocytoma
causes urtication and a flare due to histamine release
(Darier’s sign)
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Scratching and picking: scratching scale in psoriasis
makes scale appear more silver by introducing air–
keratin interfaces; more vigorous scratching produce
small bleeding points (Auspitz’s sign)
Investigations
1.
2.
3.
4.
5.
6.
Diascopy
Wood’s light
Tzanck smear
Dermoscopy
Confocal laser scanning microscopy
Biopsy
Diascopy
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Gentle pressure on lesion with a glass
slide.
Lupus vulgaris: apple jelly nodules
Nevus anaemicus
Vitiligo
Spider nevi
Erythema vs purpura
Wood’s Light
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
This is a source of ultraviolet light from which virtually all
visible rays are excluded by a Wood’s (nickel oxide) filter
Uses:
1. Tinea capitis: green flourescence
2. Erythrasma: coral pink
3. Pityriasis versicolor: yellow
4. Scabies: put flourescin on lesion to visualize burrow
5. Porphyrias: teeth, urine, faeces and serum
flouresence
6. Ash leaf macules in tuberous sclerosis
Dermoscopy

Also known as epiluminescence microscopy, is
an extension of the simple magnification.
Dermoscopes have built-in illumination.
 The oil is applied on the lesion to enhance
visibility of subcorneal structures. The lesion
examined with dermoscopes.
 The technique is mainly used in the diagnosis
of doubtful pigmented lesions
Confocal laser scanning
microscopy
Digital Scanning Photography
SITE
Face:
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Acne vulgaris.
lupus vulgaris
DLE
Melasma
Pitriasis alba.
Tuberous sclerosis.
BCC/SCC
Trunk:
Tinea.
Pitriasis
rosea.
Pitriasis versicolor.
Acne vulgaris
Psoriasis.
LIMBS
Pyoderma gangrenosum.
 Erythema nodosum.
 Erythema induratum.
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Macules:
Pinpoint: lichen nitidus
 Less than 0.5 cm: Macule
 More than 0.5 cm: Patch
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TYPE & SHAPE
Primary/secondary.
 Flat.
 Raised.
 Raised & fluid containing.
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PRIMARY RAISED LESIONS
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Papule: less than 0.5 cm
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Plaque: more than 0.5 cm
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Nodule: larger with three dimensions
Papule
Less than 5mm.
 round/oval/polygonal.
 Colour: red, pink, purple, pigmented.

How to Diagnose a skin Disease
 Papule/Plaque:
–Dome shaped: Psoriasis, Lichen planus
–Pointed: Keratosis pilaris, PRP
–Umblicated: Viral infections
–Well circumscribed plaques: Psoriasis
–Irregular plaques: Lupus vulgaris,
Shagreen patches
–Targetetoid: Stevens Jhonson synd
Plaque
Raised
 More than 0.5cm.

Nodule
circumscribed
 solid,
 palpable,
 Deep & indurated.
 More than 0.5 cm.
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PRIMARY RAISED & FLUID
CONTAINING LESIONS
Pustule.
 Vesicle.
 Cyst.
 Bullae.
 Wheal.
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Pustules
Pus containing.
 Circumscribed.
 Less than 1cm.
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Vesicle
Less than 1cm.
 Containing clear fluid.
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Cyst
More than 0.5cm.
 May contain pus, blood, sabecous
secretions, mucous.
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Bulla (blister)
Vesicle more than 0.5cm.
 May be tense/tender.
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Wheal
Transient edematous elevation.
 Pink to pale in colour.
 Cause by oedema of dermis &
capillary dilation.
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How to Diagnose a skin Disease
Vesicular
Lesions
–All viral infections present as acute
vesicular lesions: e.g. Herpes Simplex,
Herpes zoster, Moll.Contagiosum
–Autoimmune blistering diseases
present as bullous eruption
–Acute irritant contact dermatitis
How to Diagnose a skin Disease
 Purpuric
Lesions
 Leukocytoclastic vasculitis
 Henoch Schonlein purpura
 Meningococcal meningococcemia
 Drugs
How to Diagnose a skin Disease

Henoch Schonlein
purpura: palpabe
purpura on buttocks
SECONDARY LESIONS.
Crust.
 Excoriation.
 Lichenification.
 Necrosis.
 Scar.
 Scaling.
 Exfoliation.
 Fissure.
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Keratoderma.
 Vegitations.
 Erosions.
 Ulcer.
 Atrophy.
 Sclerosis.
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Crust
Dried exudate,
 May be serous, prulent,
haemorrhagic.
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Excoriation
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Haemorrhagic excavation resulting
from scratching.
Lichenification
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Thickening of skin with exagerated
skin creases.
Necrosis
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Death of skin tissue usually black in
colour.
Scar
Final stage of healing of destructive
process.
 Involve deeper dermis.
 White, smooth, shiny.
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Scaling
Desquamated horney flakes prduced
due to abnormal keratinization.
 May dry, greasy.
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Exfoliation

Splitting off of stratum corneum in
fine scales or sheets.
Fissure
Linear split or gap in skin surface.
 Usually painful.

Keratoderma
Horney thickening of stratum
corneum.
 May be congenital abnormality, or as
simple mechanical stimulation.
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Vegitations
A growth Of pathological tissue
 Consisting of multiple close set,
papillomatous masses.
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Erosion
Partial break in the epidermis.
 Heal with out scarring unless
secondary infected.
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Ulcer
A full thickness loss of skin .
 Heal by scarring.
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Atrophy
Thinning & transparency of skin by
diminution of epidermis, dermis or
both.
 Wrinkling & translucensy of skin
with Loss of skin marking.

Sclerosis
Circumscribed or diffuse hadening or
induration of the skin
 Occur as a result of dermal or
subcutenous oedema cellular
infiltration or collagen proliferration.

Surface
Rough,eg seborrheic warts.
 Smooth eg nelanocytic naevus.
 Flat topped eg lichen planus.
 Pointed eg miliaria rubra.
 Mamilliated eg compound naevus.
 Dome shape, umblicatted eg
molluscum contagiosum.
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Colour
Pink in Eczema
 Red in Psoriasis
 Brown in Pityriasis versiclor.
 Purple Papules in lichen planus.
 Red papules in scabies.

Consistency
Firm in Dermatofibroma
 Soft in Dermal mole.
 Hard in secondary deposites.
 Teethered in Scleroderma.

Margins
Discrete as in Psoriasis
 Indistinct as in Eczema.
 Activety more peripherally, with
central healing as in tinea, Lichen
planus.
 Raised & rolled in BCC
 Irregular in malignant melanoma.

Annular pattern
Can be
 maular,
 papular,
 nodular.
Reticular arrangement
Net like arrangement
 Livedo reticularis
 Cutis marmorata
 Erythema ab igne
 Oral lesion in lichen planus
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