Skin Lesions and Their Characteristics

Primary Lesions

  • Macule:

    • Definition: Flat, nonpalpable change in skin color.
    • Characteristics: Vary in sizes, shapes, and colors; usually smaller than 1 cm.
    • Examples: Rubella, scarlet fever, freckles.

  • Papule:

    • Definition: Palpable solid raised lesion that is less than 1 cm in diameter.
    • Cause: Due to superficial thickening in the epidermis.
    • Examples: Ringworm, wart, mole.

  • Nodule:

    • Definition: Solid elevated lesion larger and deeper than a papule.
    • Examples: Fibroma, intradermal nevi.

  • Scale:

    • Definition: Dry exfoliation of dead epidermis.
    • Cause: May develop as a result of inflammatory changes.
    • Examples: Very dry skin, cradle cap, psoriasis.

  • Crust:

    • Definition: A scab formed by dry serum, pus, or blood.
    • Examples: Infected dermatitis, impetigo.

  • Excoriation:

    • Definition: Traumatized abrasions of the epidermis or linear scratch marks.
    • Examples: Scabies, dermatitis, burns.

  • Vesicle:

    • Definition: A small, blisterlike raised area of the skin containing serous fluid.
    • Size: Up to 1 cm in diameter.
    • Examples: Poison ivy, shingles, chickenpox.

  • Bulla:

    • Definition: A fluid-filled vesicle or blister larger than 1 cm.
    • Examples: Burns, contact dermatitis.

  • Fissure:

    • Definition: A slit or cracklike sore extending into the dermis.
    • Cause: Usually due to continuous inflammation and drying.
    • Examples: Athlete's foot, anal fissure.

  • Ulcer:

    • Definition: An open sore or lesion that extends to the dermis.
    • Examples: Pressure sores.

  • Pustule:

    • Definition: Small elevation of skin or vesicle/bulla that contains lymph or pus.
    • Examples: Impetigo, scabies, acne.

  • Lichenification:

    • Definition: Thickening and hardening of skin from continued irritation such as intense scratching.

  • Wheal:

    • Definition: Round, transient elevation of the skin caused by dermal edema and surrounding capillary dilatation.
    • Appearance: White in center and red in periphery.
    • Examples: Hives, insect bites.

  • Plaque:

    • Definition: A patch or solid, raised lesion on the skin or mucous membrane greater than 1 cm in diameter.
    • Examples: Psoriasis.

  • Cyst:

    • Definition: A closed sac or pouch consisting of semisolid, solid, or liquid material.
    • Examples: Sebaceous cyst.

  • Scar:

    • Definition: A mark left in the skin due to fibrotic changes following the healing of a wound or surgical incision.

Secondary Lesions

  • Individual Lesions:

    • Definition: Separate and distinct.

  • Grouped Lesions:

    • Definition: Clustered together.

  • Confluent Lesions:

    • Definition: Merge so that discrete lesions are not visible or palpable.

  • Linear Lesions:

    • Definition: Form a line.

  • Annular Lesions:

    • Definition: Arranged in a single ring or circle.

  • Polycyclic Lesions:

    • Definition: Arranged in concentric circles.

  • Arciform Lesions:

    • Definition: Form arcs or curves.

  • Reticular Lesions:

    • Definition: Form a meshlike network.