This document provides classifications and definitions for primary and secondary skin lesions. Primary lesions include macules, patches, papules, plaques, nodules, vesicles, bullae, pustules, and wheals. Secondary lesions result from primary lesions and include scales, crusts, erosions, fissures, scars, atrophy, keloids, and lichenification. The document also describes the levels of fluid collection in blistering disorders and provides examples of various skin lesion shapes and arrangements.

1. CLASSIFICATION OF SKIN LESIONS
When skin diseases are described, the lesions
which come first are called as primary lesions
and those that occur on top of primary lesions
are called as secondary lesions.are called as secondary lesions.
• These definitions recommended by the
Nomenclature Committee of the
International League of Dermatological
Societies [ILDS].

2. Primary lesions
Features < 1 CM > 1 CM
Flat Macule Patch
Solid Papule Plaque,Solid
elevation
Papule Plaque,
nodule
Clear fluid Vesicle Bulla
Pus filled Pustule Pustule

3. 1.Macules :-
These are flat non palapable circumscribed
changes in skin colour< 1 cm in size.
These macules may be hyperpigmented,
hypopigmneted or depigmented.hypopigmneted or depigmented.
Level of melanin Clinical colour (due to tyndall
effect and light scattering from the
melanin residing in various layer )
Epidermis Brown
Upper dermis Purple red (violaceous)
Lower dermis Blue, slate grey

4. A. Brown colour macule

5. B.Purple Red colour macule

6. C. Blue colour macule

7. D.HYPOPIGMENTED MACULE

8. 2.PATCH
A Large macule is called patch ( >1 cm in size)
May have scaling
E.g :-vitiligo, melesma , P.alba

9. Leprosy
hypopigmented
Patch / plaque

10. Examples of patch
MelesmaVitiligo

11. 3.papule
• solid elevation with no visible fluid <1 cm size
A. Flat topped papules :-
lichen planus
B. Umblicated papules:-B. Umblicated papules:-
Molluscum contagiosum
• Papules may be various colour

13. Flesh colour yellow and white coloured
papules

14. Brown coloured papules

15. Red coloured papules
Papular
Papular urticaria

16. BLUE COLOUR PAPULE

17. 4.PLAQUE
• An elevated circumscribed lesion greater than 1 cm
diameter; its surface is usually flat
• Confluence of many papules creates an elevated
lesion >1 cmlesion >1 cm
• (horizontal length > vertical depth )

18. Erythematous Scaly Plaque psoriasis

19. 5.NODULES
• Solid,round or Ellipsoidal palpable lesion that has
a diameter >1cm
• Vertical depth > horizontal length
[contrast from plaque][contrast from plaque]
• More arise from dermis or subcutaneous tissue

21. Other example of nodules
Xanthoma Kerato-acanthoma

22. 6.Vesical
• Fluid filled cavity < 1 cm raised above the
plane of surrounding skin

24. Other examles of vesicle
• Impetigo
• Herpis simplex• Herpis simplex

25. Other examles of vesicle
• Dermatitis herpetiformis

26. 7.Bulla
• Larger vesical >1 cm
• A fluid filled,raised often a translucent lesion

27. Bullus

28. 8.Pustules
• A vesicle filled with pus
• Raised area In the epidermis or hair containing
Pus
• It is formed due to collection of inflammatory• It is formed due to collection of inflammatory
exudate rich in leucocytes.
• It may contain bacteria or may be sterile.

29. pustular
Sec.
infection
causes
pustule

30. 9.Abscess
• A localized collection of pus deep in dermis or
subcutaneous tissue.
• Due to deep seated location pus may not be
visible on skin surface but would show sign ofvisible on skin surface but would show sign of
inflammation.

31. 10.Wheal
• Transient elevated edematous lesions. Result
of edema produced by the escape of plasma
through vessel walls in the upper portion of
dermisdermis
Classical urticaria

33. 11.Cyst
• It is spherical or oval sac or encapsulated
cavity containing fluid or semi solid material.
• It is lined with true epithelium
• Eg: mucous retention cyst• Eg: mucous retention cyst

34. Level of fluid collection and their
clinical correlation

35. Epidermal DEJ AND DERMIS
1.Subcorneal
Immediately below corneum,
& Granular
1.Rest of epidermis
(spinous layer ,suprabasal
and basal layers)
2.Very2.Very flacciedflaccied ( so fragile that
blisters rupture and are
almost never seen clinically )
2. Flaccied but lesser than
subcorneal blisters (hence
less fragile and intact loose
blisters may sometimes be
seen clinically )
3.Rupture very easily. 3.Rupture easily
1. Tense blister (hence
intact blister are usually
seen clinically )
2. Donot rupture easily
as they are tense
3. Heals with scar and3.Rupture very easily.
presents not as erosions but
as crusts/scales (usually no
visible erosions)
3.Rupture easily
Presents as erosions
4.Heal with normal skin
No Scar
4.Heal with
Hyperpigmentation
No scar
•pemphigus foliaceus,
•Staphylocoous scalded
skin syndrome
•Bullous impetigo
•pemphigus
vulgaris,
•Toxic epidermal
necrolysis
3. Heals with scar and
milia
4. Heals with
hypopigmentation
• Bullous pemphigoid

36. Epidermal
Subcorneal
Immediately below corneum,
& Granular
Rest of epidermis
(spinous layer ,suprabasal
and basal layers)
Dej and dermal
VeryVery flacciedflaccied ( so fragile that
blisters rupture and are
almost never seen clinically )
Flaccied but lesser than
subcorneal blisters (hence
less fragile and intact loose
blisters may sometimes be
seen clinically )
Tense blister (hence intact
blister are usually seen
clinically )
Rupture very easily .present
not as erosions but as
crusts/scales (usually no
Rupture easily
Presents as erosions
Donot rupture easily as they
are tense
crusts/scales (usually no
visible erosions)
Do not heal with scar Do not heal with scar Heals with scar and milia
Heal with normal skin Heals with
hyperpigmentation
Heals with hypopigmentation
Eg:-
•pemphigus foliaceus,
•Staphylocoous scalded
skin syndrome
•Bullous impetigo
Eg:-
•pemphigus vulgaris,
•Toxic epidermal necrolysis
Eg:-
•Bullous pemphigoid

37. Secondary skin lesion
1. Scale
2. Crust
3. Erosion
4. Fissure4. Fissure
5. Scar
6. Atrophy
7. Keloid
8. Lichenification

38. 1.Scale [Exfoliation]
• Excess dead epidermal cells that are produced
by abnormal keratinization and shedding
• Eg:- psoriasis, Icthyosis

39. Types of scale
Silvary /mica type Psoriasis
Collarette scale Pityriasis rosea
Yellow , Greasy scale Seborrheic dermatitis
Leaf like Pamphigus foliaceousLeaf like Pamphigus foliaceous
Wickham’s Striae Lacy white pattern overlying purpule
papule / plaques in lichen planus
Fish like scale Ichthyosis vulgaris
Powdery, branny fine
scales
Pityriasis versicolor

41. Ichthyosis vulgaris
Fish-like scalesFish-like scales

45. 2.Crust(scab)
• Dried exudate (dried serum, pus ,or blood )
mixed with epithelial and sometime bacterial
debris
– Golden yellow, Honey colored crust –seen in non– Golden yellow, Honey colored crust –seen in non
bullous impetigo
– Hemorrhagic crust seen in toxic epidermal
necrolysis

46. Honey colour crust –
in NON BULLOUS IMPETIGO

47. HEMORRHAGIC
CRUST ON LIPS IN
TENTEN

48. EROSIONS,ULCER, FISSURE
1. EROSION :-RAW LESION DUE TO LOSS OF ONLY THE EPIDERMIS
(SO DONOT LEAVE SCAR )
2. ULCER :- LESION DUE TO LOSS OF EPIDERMIS AND DERMIS AS INJURY IS
IN DEJ AND DERMIS (IT HEALS WITH SCAR )

49. 2.Erosions

50. EROSION IN PHEMPHIGUS VULGARIS

51. 3.ULCER

52. TROPHIC ULCER – PUNCHED OUT VERTICAL
ULCER IN HENSONS DISEASE

53. UNDERMINED ULCER IN
CUTANEOUS TB

54. • Eg of ulcer :- chancroid

55. • Pyoderma Decubitus
gangrenosum

56. 4.FISSURE

57. FISSURRE

58. 5.SCAR

60. 6.ATROPHY

61. 7.KELOID

62. 8.Lichenification (lichen simplex chronicus)
• In chronic itchy diseases repeated rubbing of
the skin induces a reactive process in the skin
called as lichenification .
• it is a triad of• it is a triad of Thickened skin
Hyper pigmentation
Increased skin
markings

63. Lichenification

64. Special lesions
1. Burrow
2. Comedone
3. Telengiectasia3. Telengiectasia
4. Poikiloderma
5. Purpura

65. 1.Burrow
Scabies mite

66. 2.Comedone
• Occlusion of hair follicle by keratin and sebum
1. open/ black 2. Closed /white
Two types
1. open/ black
comedones
2. Closed /white
comedones
• When the keratin plug in the
pilosebaceous duct is open
to the surface , the content
oxidizes and becomes black
•When the keratin plug in the
pilosebaceous duct is deep inside
and is closed to air hence there is
no oxidization.
• Seen in acne ,
• hidradenitis suppurativa

67. 3.Telengiectasia
• Permanent dilatation of small capillaries in the
superficial dermis that are visible as thin red
lines or net like patterns on the skin.
1. Dermatomyositis1. Dermatomyositis
2. Systemic sclerosis

68. 4.Poikiloderma
it is a triad of
Skin atrophy
Varied pigmentation
(both Hyper and
hypo pigmentation)
Telangiectasia

69. 5.Purpura

70. Shapes and arrangment of skin lesion
• 1.Annular :-
• Ringed shaped Edge is active( either raised
,scaly or with a different colour),
• Central is clear• Central is clear
Tinea

71. 2.Discoidal/nummular/coined-shaped
• Edge and central both equally active ,no
central clearing
1. DLE
2. Discoid eczema2. Discoid eczema

72. 3.Linear nodules and disharging sinus
along lymphatics
• Lesions are nodular and are distributed
linearly along lymphatics
• They brust creating sinuses along these
lymphatics.lymphatics.

73. • Seen in
1. Sporotricosis ;-caused by sporothrix schenckii
2. Fish tank granuloma(swimming pool granuloma)
caused by mycobacterium marinum.

74. 4.Target lesion/iris lesion/bull’s eye lesion
• Lesion resemble targets with at least 3 distinct
zones .
• Seen in erythema multiforme minor
• Erythema chronicum migrans (skin sign in• Erythema chronicum migrans (skin sign in
lyme’s disease)

76. 5.Dermatomal
• Along a spinal or cranial nerve root .
• These lines are oriented horizontally on trunk
(along intercostal nerves),
• longitudianal along limbs (along peripheral• longitudianal along limbs (along peripheral
nerves) or cranial nerves
– Seen in Herpes zooster

77. 6.Blaschkoid
• Along the blaschko line
• Blaschko lines are lines of skin cell migration
during embryogenesis
(not along nerve vessels lymphatics)(not along nerve vessels lymphatics)
• It is longitudinally oriented on the limbs and
curved/ S-shaped on the trunk

79. The diseases comes along blaschko
lines are:-
1. Incontinentia pigmenti
2. Segmental vitiligo
3. Linear verrucous epidermal nevus(LVEN)3. Linear verrucous epidermal nevus(LVEN)
4. Psoriasis
5. Lichen planus

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