Primary Lesions Summary
- 1. Macule: Flat circumscribed area of change in skin color
- 2. Papule: small circumscribed elevation of the skin
- 3. Nodule: Solid, circumscribed elevation of the skin whose greater part is beneath skin surface (felt more than seen)
- 4. Plaque: flat topped palpable lesion (gathering of papules)
- 5. Vesicle: collection of clear fluid (<5mm in diameter)
- 6. Bulla: like vesicle, but > 5 mm
- 7. Wheal: Transient, slightly raised lesion with pale center and pink margin. Seen in urticaria.
- 8. Purpura: Visible collection of blood under the skin e.g. Vasculitis
- 9. Telangectasia: Dilated capillaries visible on skin surface
- 10. Burrow: Tunnel in the skin (e.g. Scabies)
Primary skin lesions
Macule
- (L. macula, “spot”)
- A macule is flat; if you can feel it, then it is not a macule.
Macule Examples
Patch
- Patches are flat but larger than macules
- If it’s flat and larger than 1 cm, it is a patch
Patches Examples
Papule
- A papule is a circumscribed palpable elevation of the skin less than 1 cm in diameter
- Dermal (drug eruption, lipid deposits), epidermal (warts, molluscum), or both (lichen planus)
Plaque
- A slightly raised lesion greater than 1 cm in diameter
- Papules confluence (psoriasis)
- Patch thickening (mycosis fungoides the lymphoma of the skin)
Plaques Examples
Nodule
Palpable solid deep lesion (depth > diameter)
- Epidermal
- Dermal
Vesicle
- A raised lesion less than 0.5 cm in diameter containing clear fluid
Bulla
- A vesicle that is greater than 0.5 cm in diameter is known as a bulla.
Pustule
- A pustule is a raised lesion less than 0.5 cm in diameter containing yellow fluid, which may be sterile as in acne and pustular psoriasis, or infected.
Sterile pastules; ABCD - seen in acne, psoarsos, bacterial staph, commidone?
Wheal
- A wheal is a transient, itchy, pink or red swelling of the skin, often with central pallor.
Cyst
palpable soft sac containing fluid.
- Epidermal
- Dermal
Telangiectasia
- Dilatation of capillaries gives rise to this skin condition.
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