This document provides information on describing basic skin lesions, including their morphology, types, shapes, configurations, arrangements, distributions, and primary and secondary lesions. It discusses features to note when describing a skin lesion such as size, type, shape, color, surface area, and distribution. It also defines different types of primary lesions like macules, patches, papules, plaques, nodules, vesicles, bullae, pustules, abscesses, wheals, and cysts as well as secondary lesions including scales, crusts, erosions, fissures, and scars. Finally, it covers some special skin lesions such as burrows, purpura, ulcers, and malar rashes.

1. Basic skin lesions & their
morphology
Prepared by : Temesgen Girma
C1 Medical student, SPHMMC, Addis Ababa, Ethiopia

2. When describing a skin lesion,it is important to
note the following features:-
1. Size
2. Type
3. shape and symmetry
4. color and pigmentation
5. surface area
6. Distribution over the body surface

3. Types of lesion
• Primary skin lesions are those which develop as a direct result of the
disease process.
• Secondary lesions are those which evolve from primary lesions or
develop as a consequence of the patient's activities.
• special skin lesion :- Specific for certain disease

4. SHAPES OF PAPULES AND NODULES
• Dome shaped
• Flat shaped
• Umblicated
• Acuminate

5. CONFIGURATION OF LESIONS
• Annular
• Round/ discoid
• Polycyclic
• Arcuate
• Linear
• Reticular
• Serpiginous

6. ARRANGEMENT OF LESIONS
• Grouped/ herpetiform
• Scattered

7. DISTRIBUTION OF LESIONS
• Sun exposed
• Sun protected
• Acral
• Truncal
• Extensor
• Flexor
• Localized
• Generalized
• B/L symmetrical
• Universal

8. Primary skin lesions
• Macule
• Patch
• Papule
• Plaque
• Nodule
• Vesicle
• Bulla
• Pustule
• Abscess
• Wheal
• Cyst

9. A. Macules
• A flat circumscribed lesion
showing change in color
without change in its
consistency.
• Macules are nonpalpable.
• They are 0.5cm-1cm in size.

11. patch
• A large macule is called
patch (>1cm in size).
• May have scaling.
• Eg :- Vitiligo, melasma,
pityriasis alba

12. Papules
• A small, solid lesion,
<0.5 cm in diameter,
raised above the surface
of surrounding skin &
hence palpable.
• Papules may be of
various colors.

13. Plaque
• It is an indurated area of
skin larger than 0.5 cm
in diameter which may
be raised or depressed
from skin surface.

14. Nodule
• A large ( 0.5 – 5.0 cm ), firm
lesion raised above the surface
of surrounding skin.
• It is the depth of involvement
that differentiates a nodule from
a large papule.
• Surface- smooth,
keratotic,ulcerated or fungating.

16. Vesicle
• A small, fluid filled
lesion, <0.5 cm in
diameter, raised above
the plane of surrounding
skin.
• Fluid is often
visible and the lesions
are translucent

17. Bulla
• A fluid filled, raised,
often a translucent
lesion >0.5cm in
diameter
E.g. Bullous pemphigoid

18. Pustule
• A vesicle filled with pus
• It is formed due to
collection of
inflammatory exudate
rich in leucocytes.
• It may contain bacteria
or may be sterile.

19. 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 of
inflammation.

20. Wheal
• It is a transient swelling
of skin disappearing
within 24 hrs.
• It is formed due to
sudden extravasation of
fluid in the dermis.
• E.g: urticaria

21. Cyst
• It is a spherical or oval
sac or an encapsulated
cavity containing fluid
or semi solid material.
• It is lined with true
epithelium.
• E.g:- mucous retention
cyst

22. Secondary Skin Lesions
• Scale
• Crust
• Erosion
• Fissure
• Scar

23. Scale
• Excess dead epidermal
cells that are produced
by abnormal
keratinization and
shedding
• Eg: Psoriasis, Icthyosis

24. Staphylococcal scalded skin syndrome

25. Crust
• Dried exudate of body
fluids (blood / serous
fluid)
• Which might be either
yellow / red

26. Erosion
• A focal loss of epidermis
• Erosions do not
penetrate below the
dermoepidermal
junction and therefore
heal without scarring
• Eg:- tinea pedis

27. ulcer
• A focal loss of epidermis
and/or dermis
• Scarring depends on the
depth of the ulcer

28. Fissure
• It is a linear loss of continuity of
skin due to excessive tension.
• Eg:- eczema(fingertips)

29. Scar
• It is replacement of
normal skin by fibrous
tissue in the process of
healing of damaged skin.
• Scars are of two
typeshypertrophic and
atrophic.

30. Special Lesions
• Burrow
• Purpura
• Ulcer
• Malar rash

31. Burrow
• It is a serpentine tunnel
made by scabies mite in
stratum corneum.
• The open end of the
tunnel has a papule.

32. Purpura
• Extravasation of red
blood cells from
cutaneous vessles in skin
& mucous membrane.
• Diascopy- non blanchable.

33. Malar Rash of lupus
• is red or purplish and mildly
scaly.
• the rash spares the nasolabial
folds of the face
• It is usually macular with sharp
edges, and not itchy

34. Thank You!