Introduction to Skin Lesions

1. SKIN LESIONS
FINAL YEAR 2021

2. Basic facts about the skin
• The skin is the largest organ of the body, with
a total area of about 20 square feet.
• The skin protects us from microbes and the
elements, helps regulate body temperature,
and permits the sensations of touch, heat, and
cold.
• Skin has three primary layers:

3. -: The epidermis, the outermost layer of skin,
provides a waterproof barrier and creates our
skin tone.
- The epidermis is made up of these layers :
• Stratum corneum
• Stratum lucidum
• Stratum granulosum
• Stratum spinosum
• Stratum basale

4. -:The dermis, beneath the epidermis, contains
tough connective tissue, hair follicles, and
sweat glands.
-: The deeper subcutaneous tissue (hypodermis)
is made of fat and connective tissue.
• The skin’s color is created by special cells
called melanocytes, which produce the
pigment melanin. Melanocytes are located in
the epidermis.

5. Lesions of the skin
• PRIMARY LESIONS
• SECONDARY LESIONS
• SPECIAL LESIONS

6. PRIMARY LESIONS
• These are lesions that occur on non
pathological skin/normal skin, which have not
being altered by trauma or manipulation(
scratching, scrubbing).
• They include :
- Macule
- Papule
- Patch

7. - Plaque
- Nodule
- Wheal
- Vescicle
- Bullae
- Pustule
- Cyst

8. SECONDARY LESIONS
• These are lesions that result from
modifications of a primary lesion from
traumatic injury, evolution of a primary lesion
and other external factors.
• They include:
- Crust
- Scale
- Erosion

9. - Ulcer
- Fissure
- Sinus
- Scar
- Atrophy
- Excoriation
- Lichenification
- Infarct

10. SPECIAL LESIONS
• These may also be referred to as tertiary
lesions and include :
- Burrow
- Comedo
- Milium
- Striae
- Target lesion
- Horn

11. - Sclerosis
- Poikiloderma

12. MORPHOLOGY OF SKIN LESIONS
• Skin lesions can be :
- Raised : papule, plaque, nodule, cyst, wheal, scar,
comedo, horn
- Depressed : erosions, straie, burrows, ulcer,
atrophy, sinus
- Flat : macule, patch erythema
- Surface changed: crust, scale, fissure, excoriation
- Fluid filled: vescicle, bullae, pustule, abcess
- Vascular : purpura, telengectasia