MORPHOLOGYPrimary Lesions
Secondary LesionsSpecial Lesions
Primary Lesions
Macule• Flat discoloration (any color) up to 1 cm
Patch• Flat discoloration (any color) greater than
1 cm
Papule• Palpable lesion up to 1 cm• May become confluent to form plaque
Plaque• Palpable lesion greater than 1 cm
Nodule• Circumscribed, elevated, solid lesion
greater than 1 cm
Tumor• A very large nodule
Vesicle• Circumscribed collection of free fluid up to
1 cm
Pustule• Circumscribed collection of pus up to 1
cm
Bullae• Circumscribed collection of free fluid
greater than 1 cm
Wheal (hive)• Firm, edematous
plaque resulting from infiltration of the dermis with fluids
• Transient; may last only a few hours
Secondary Lesions
Scales• Excess dead epidermal cells that are
produced by an abnormal keratinization and shedding
Crust• Collection of dried serum and cellular
debris (a scab)
Erosion• Focal loss of
epidermis• Does not pass the
dermoepidermal junction
• Heals without scarring
Ulcer• Focal loss of epidermis and dermis• Heals with scarring
Fissure• Linear loss of
epidermis and dermis with sharply defined nearly vertical walls
Atrophy• Depression in the skin
resulting from thinning of the epidermis or dermis
Scar• Abnormal formation of
connective tissue implying dermal damage;
• After injury or surgery scars are initially thick and pink but with time become white and atrophic
Special skin lesions
Comedone• Plug of sebaceous
and keratinous material lodged in the opening of a hail follicle
• Closed comedone = white head
• Open comedone = black head
Excoriation• An erosion caused by scratching; often
linear
Lichenification• Area of thickened
epidermis induced by scratching
• Skin lines are accentuated so that the surface looks like tree-barking
Petechiae• Circumscribed tiny deposit of blood (up to
0.5 cm)
Purpura• Circumscribed deposit of blood greater
than 0.5 cm
Ecchymoses• Very large purpuric lesions
Name that lesion!Use the proper terminology to
describe the predominant lesion (primary, secondary or special) shown in the following photos.
Macules
Papules
Pustules
Nodule
Patch
Tumor
Vesicles
Vesicles
Scales
Crust
Patches
Fissures
Atrophy
Lichenification
Comedones
Erosion & Crust
Bullae
Papules
Fissures
Plaques
Lichenification