This document provides an overview of common terminology used to describe diseases of the skin. It discusses terms used to describe the distribution, shape, color, type of lesions, secondary changes, epidermal changes, and histological changes that can be seen in various skin diseases. Some of the key terms mentioned include macule, papule, plaque, nodule, vesicle, bulla, pustule, abscess, desquamation, crusting, ulcer, erosion, fissure, atrophy, cicatrix, telangiectasis, acantholysis, acanthosis, basophilic degeneration, spongiosis, dyskeratosis, and hyperkeratosis. The document serves as

1. Diseases of Skin

2. Common Terminologies
• Dermatosis / Dermatoses : Any cutaneous lesion or group
of lesions. Any Skin Disease
• Genodermatoses : Hereditary skin disorders, many of
which also accompanied by various systemic
manifestations of different altered enzyme functions.
• Genokeratoses : Hereditary skin diseases which are
characterized particularly by alterations in normal
keratinization process

3. • Dermatitis : Inflammation of skin. Not a final diagnosis
• Lesion : An area of altered skin. It can be solitary or multiple
• Rash: Widespread eruption of lesions

5. Distribution of Lesions
• Acral : Affecting the distal portions (extremities) of limbs
(hand & foot) and head (ears, nose, etc)
• Dermatomal: Corresponding with nerve root distribution
• Seborrheic : areas of skin which have a tendency to be oily.
Such as scalp, behined ears, eyebrows, nasolabial fold, etc
• Intertriginous : Area is where two skin areas may touch or
rub together. Examples of intertriginous areas are the axilla
of the arm, the anogenital region, between digits, etc

7. Shape of Lesions
• Annular: Lesions grouped in a circle
• Linear / Striate: Line like
• Reticular : Net-like
• Serpiginous : skin lesion having a wavy margin / Snake
like appearance
• Discoid / Nummular : Round or Coin shaped
• Herpetiform: Grouped or clustered vesicles or ulcers
• Morbilliform : A rash which looks like measles
• Target / Iris lesion: lesions having concentric rings like a
bulls-eye or archery target

8. Annular: Lesions grouped in a circle

9. Reticular : Net-like

10. Serpiginous : lesion having a wavy margin

11. Discoid / Nummular : Round or Coin shaped

12. Herpetiform: Grouped or clustered vesicles or ulcers

13. Morbilliform : A rash which looks like measles

14. Target /Iris lesion: lesions having concentric rings like a bulls-eye

15. Colour of Lesions
• Erythema : red skin due to increased blood supply and it
will blanch on pressure.
• Purpura : is bleeding into the skin
• Petechiae : Pin-point small red or purple spot caused by
bleeding into the skin.
• Ecchymoses : a subcutaneous spot of bleeding with
diameter larger than 1 centimeter
• Hyperpigmentation : may be caused by excess of melanin
or haemosiderin deposits that result in skin colour that is
darker than normal.
• Hypopigmentation : is loss of normal melanin and results
in skin colour that is paler than normal but not completely
white.

16. Erythema : red skin due to increased blood supply

17. Petechiae

18. Ecchymoses

19. Hyperpigmentation

20. Hypopigmentation

21. DiscreteLesions
• Macule : Circumscribed alterations in skin color less than
1 to 1.5 cm in diameter. The skin surface is neither
elevated or depressed in relation to the surrounding skin .
The surface is smooth.
• Patch : A large area of colour change (> 2cms) with a
smooth surface.
• Papule : A small raised or elevated palpable lesion less
than 0.5 cm in diameter.
• Plaque : is a raised or elevated palpable flat lesion greater
than 0.5 cm in diameter.
• Nodule : A swelling or enlargement of a papule in three
dimensions (height, width and length).

22. Macule

24. Papule

25. Plaque

26. Nodule

27. • Blister: Accumulation of fluid either within or below the
epidermis and mucous membrane
• Vesicle: Elevated fluid filled blister containing clear fluid
that is lesser than 0.5 cm in diameter
• Bulla: Elevated fluid filled blister containing clear fluid
that is greater than 0.5 cm in diameter
• Pustule : Circumscribed elevation of the skin that contains
a purulent exudate that may be white, yellow, or greenish-
yellow in color.
• Abscess : A localized collection of pus in a cavity formed by
disintegration or necrosis of tissue.

28. Vesicle

29. Bulla

31. Epidermal Changes
• Desquamation / Exfoliation: skin coming off in scales.
• Psoriasiform - large white or silver flakes, as in psoriasis.
• Pityriasiform - a branny powdery scale.
• Lichenoid - when scale is tightly adherent to the surface
of the skin.
• Keratotic - horny scale with plenty of keratin.
• Maceration - moist peeling skin.
• Verrucous - resembling a wart.

32. Desquamation

33. Psoriasiform

34. Pityriasiform

35. Verrucous

36. Secondary Changes
• Crusting: Crusts result when serum, blood, or purulent
exudate dries and it is a hallmark of pyogenic infection.
Crusts are yellow when they have arisen from dried
serum; green or yellow-green when formed from purulent
exudate; and brown or dark red when formed from blood.
• Ulcer : A discontinuity in skin or mucous membrane with
complete loss of epidermis and possible loss of dermis
• Erosion : a loss of epidermis above the basal layer, leaving
denuded surface.
• Fissure : Thin crack within the epithelium or linear
cleavages or gaps in the skin surface

37. Crusting

38. Ulcer

39. Erosion

40. Fissure

41. • Atrophy : Atrophy of the skin may involve the epidermis,
or the dermis, or both. It is the thinning process
associated with decreased number of cutaneous cells.
• Cicatrix (scar) : variety of dermal and epidermal changes
associated with wound healing and resulting in fibrous
tissue replacing normal tissue in the affected areas.
• Telangiectasis : localized group of superficial distended
blood capillary vessels. It appears as a red spot that may
look spidery and that blanches when pressure is applied

42. Cicatrix

43. Telangiectasis

44. Histological Changes
• Acantholysis: loss of intercellular connections
(desmosomes) between keratinocytes
• Acanthosis: thickening of prickle cell layer in epithelium.
• Basophilic degeneration: age and sunlight related changes
of collagen and elastic fibers
• Spongiosis: intraepidermal edema, causing splaying apart
of keratinocytes in stratum spinosum (resembling a
sponge), vesicles due to shearing of desmosomes
• Dyskeratosis : abnormal, premature keratinization of
keratinocytes below granular cell layer; often have
brightly eosinophilic cytoplasm
• Hyperkeratosis: thickened cornified layer

45. Acantholysis

46. Acanthosis

47. Basophilic degeneration

48. Spongiosis

49. Dyskeratosis

50. Hyperkeratosis