Skin Lesion Recognition Flashcards
Types of skin lesion
Primary, secondary or both
Level of skin lesion
Flat, elevated, depressed
Primary lesion
Direct result of disease process
Early lesion
Not altered by trauma
Examples of primary lesions
Papules Macules Vesicles Nodules Pustules Patches Bullae Cysts Plaques Wheals
Papule
Small solid elevation
Up to 1cm
Due to infiltration of inflammatory cells and edema
- flea bites, superficial bacterial folliculitis
pustule
Small circumscribed elevation filled w purulent material
Intra epidermal, follicular or non follicular
- bacterial infection, pemphigus foliaceus
Pemphigus foliceus early lesion
Non follicular pustules
Pemphigus foliaceus late lesions
Leads to crust and erosions
Plaque
Flat topped elevation
Formed by coalition of papules
- eosinophilic plaques in cats
Calcinosis cutis (cushings)
Wheal
Sharply circumscribed raised lesion or hive
Consist of edema
Appear/disappear within m to h
- urticaria, insect bites, intradermal test
Macula
Flat circumscribed skin discoloration <1cm in diameter
Lacks surface elevation or depression
-loss of pigment, erythema (red), hyperpigmentation
Common in vitiligo, atopic dermatitis
Patch
Flat circumscribed skin discoloration >1cm in diameter
Canine atopic dermatitis
vesicle
Sharply circumscribed elevated lesion <0.5cm
Contains fluid
- viral disease, autoimmune disease (chicken pox lesion)
Same thing as a bulla just smaller
Bulla
Sharply circumscribed elevated lesion >0.5cm*
Contains fluid
- common lesion in autoimmune disease
Same thing as a vesicle just bigger
Nodule
Solid circumscribed elevated lesion >1cm in diameter
Usually extends into dermis
- neoplasia, deep infection, immune mediated lesion
Cyst
Nodule containing fluid or semisolid material
- follicular cyst, Infundibular cyst, apocrine cyst
Secondary lesion types
Erosions Ulcers Excoriations Fissures Scars Epidermal collarette Lichenification
Erosion
2nd
Partial loss of epidermis, does not penetrate basement membrane, heals without scaring
Ulcer
2nd
Full loss of epidermis, penetrate and extend beyond basement membrane, heals w scarring (in chronic cases)
Excoriation
2nd
Linear erosion induced by scratching or trauma
Seen in pruritic dermatoses
- atopic dermatitis, scabies, pyoderma
Fissure
2nd
Verticals loss of epidermis and dermis with sharply defined walls/cracks in the skin
Scar
2nd
Formation of new connective fibrous tissue
Implied prior damage that extended beyond basement membrane
Epidermal collarette
2nd
Circular ring of scales w erythema
Non-expanding - footprint of ruptured pustule
- superficial pyoderma
- sterile pustular dermatosis
expanding
- collarette expands, peeling/lifting of stratum corneum, exfoliating toxins by staph Pseudointermedius
Non expanding collarette
Non-expanding - footprint of ruptured pustule
- superficial pyoderma
- sterile pustular dermatosis
Expanding collarette
expanding
- collarette expands, peeling/lifting of stratum corneum, exfoliating toxins by staph Pseudointermedius* most common cause of pyoderma in dogs
Lichenification
Marked thickening of all layers of epidermis
Resembles tree bark
Accentuation of skin lines
Caused by chronic rubbing or scratching
- canine atopic dermatitis
Hyperkeratosis
Increase in the thickness of the stratum corneum
• Associated with: Atopic dermatitis with malassezia dermatitis, Chronic low-grade trauma/barrier damage or secondary infection
Zinc- responsive dermatosis, malassezia dermatitis,
ectoparasitism
Primary or secondary lesions
Alopecia
Scales
Crusts
Follicular casts
Comedones
Hyperpigmentation/hypopigmentation
Spontaneous (primary) alopecia
Border of lesion has a sharp margin
Tip of hair usually not affected
Easily epilated hair shaft at borders
- Dermatophytosis, dermodicosis, ischemic Dermatopathy
Self induced (secondary) alopecia
Border of lesion may have indistinct margin
Tip of hair at border is broken
Hair shaft isn’t easily pulled
Scale
Accumulation of loose fragments of stratum corneum - flakes
Due to maturation of epidermis or glandular secretion
Primary scaling lesion
Primary seborrhea of spaniels
Ichthyosis
Sebaceous adenitis
Scaling secondary lesion
Xerosis (dry skin)
Flea allergy dermatitis
Canine atopic dermatitis
Pyoderma
Ectoparasites
Crust
Collection of cellular debris, dried exudate, inflammatory cells or blood
- yellow, honey, dark red, brown
Primary crust lesion
Zinc responsive dermatosis
Hepatocutaneous syndrome
Secondary crust lesion
Pyoderma
Pruritus
Pemphigus foliaceus
Follicular cast
Accumulation of keratin and sebaceous material that adheres to hair shaft
Primary associated w - primary seborrhea, sebaceous adenitis
Secondary lesion associated w - Dermatophytosis, dermodicosis
Comedo
Dilated hair follicles filled w cornified cells & sebaceous/sweat gland secretions
Primary lesion of feline chin acne, schnauzer comedo syndrome
Secondary lesion of hyperadrenocorticism, dermodicosis
Colors of lesions
Erythema
Petechia /purpura
Hypopigmentation
Hyperpigmentation
Erythema
Redness of skin - rash
Caused by congestion (vasodilation) of BV in dermis
Blanches on pressure - diascopy
- allergic dermatosis, cutaneous drug reaction, cutaneous lymphoma
Petechia/purpura
Dark red/purple
Caused by extravasation of RBC into dermis - hemorrhage
Does not blanch on pressure
Petechia < purpura < ecchymosis
- vasculitis, drug reaction
Hypopigmentation
Lighter than normal skin color
Depigmentation = total loss of pigmentation (white)
- vitiligo, cutaneous lymphoma, albinism, uveodermatologic syndrome
Hyperpigmentation
Darker than normal skin color
- hypothyroidism or post inflammation response
Primary lesions that are only different in size
Macule vs patch
Vesicle vs bulla
Primary lesion filled w fluid/inflammation
Papule - inflammatory cells & edema
Pustule - purulent material
Wheal - edema
Vesicle & bulla - fluid
Cyst - fluid/semisolid material
What primary lesions are flat?
Plaque
Macule
Patch
What primary lesions are raised?
Papule
Pustule
Wheal
Vesicle
Bulla
Nodule
Cyst
Multiple papules form a
Plaque
