05 - Secondary Lesions

Question 1

(Secondary Lesions)

(Scar)

1. what is it?
2. most scars are what?
3. proliferative scars do occur in what?
4. Differentials?

Answer 1

1. an area of fibrous tissue that has replaced severe damage to the dermis or subcutaneous tissue
2. alopecic, atrophic, and depigmented
3. in dark-skinned dogs and can be alopecic and hyperpigmented
4. Previous severe damage to the skin such as severe burns, and deep pyoderma

Question 2

(Erosion)

1. what is it?
2. generally results from what?
3. differentials?

Answer 2

1. a shallow break in continuity of the epidermis that does not penetrate the basal cell layer and consequently heals without scarring
2. epidermal diseases and self inflicted trauma
3. Self-trauma; immune-mediated disorders (pemphigus vulgaris, lupus erythematosus); post-rupture of subcorneal pustule/vesicle; pseudomonas ear infection

Question 3

(Ulcer)

1. what is it?
2. What is required for an ulcer to form?
3. What is commonly formed after ulcer heals?
4. differentials?

Answer 3

1. deeper break in the continuity of the epidermis, with the exposure of the underlying dermis
2. a deep pathologic process
3. a scar
4. Severe trauma; deep pyoderma; deep fungal infections; neoplasia; feline eosinophilic ulcer; immune mediated disorders (e.g. bullous pemphigoid, systemic lupus erythematosus); cutaneous vesicular lupus (formerly known as: idiopathic ulcerative dermatitis of Collies and Shelties); vasculopathies

Question 4

(Excoriation)

1. what are they?
2. recognized by what?
3. differentials?

Answer 4

1. erosions or ulcers caused by scrathcing, biting, rubbing. they are self-inflicted and often associated with secodnary bacterial infection
2. linear pattern
3. self-trauma usually from pruritis (scratching, biting, rubbing)

Question 5

(Epidermal Collarette)

1. what is it?
2. OFten indicated what?
3. differentials?

Answer 5

1. superficial lesion arranged as a circular rim of loose keratin
2. superficial staphylococcal infection
3. Slowly expansive superficial “spreading” pyoderma. It can sometimes represent the remnants of the “roof” of a vesicle, bulla or pustule

Question 6

(Lichenification)

1. what is it?
2. often a result of what?
3. color?
4. lichenifcation indicates what?
5. diff?

Answer 6

1. thickened, hardened skin with exaggerated superficial skin markings (it resembles elephant hide)
2. friction
3. often normal - may be erythematous but is often hyperpigmented
4. chronic inflammation
5. Chronic trauma to the epidermis usually secondary to pruritus or friction. Malassezia and staphylococcus infections may be secondarily present in lichenified skin.

Question 7

(Draining Sinus Tracts)

1. what is it?
2. may result from what?
3. Differentials?

Answer 7

1. ulcerated tracts in the skin usually originating in the deep dermis or subcutaneous fat.
2. underlying osteomyelitis (bone infection)
3. Deep pyoderma (furunculosis=rupture of hair follicle); subcutaneous or deep mycotic infections; mycobacteriosis, sterile panniculitis; foreign body granulomas; osteomyelitis.

Question 8

(Hyperkeratosis)

1. what is it?
2. Diif?

Answer 8

1. increase in thickness of the straum cornum (horny layer)
2. 1. Callus; idiopathic hyperkeratosis of the planum nasale.
3. Hyperkeratosis of the footpads: pemphigus foliaceous; superficial necrolytic dermatitis; zinc-responsive dermatosis; distemper; idiopathic hyperkeratosis of the footpads (seen more frequently as an old age change).

Question 9

(Fissure)

1. what is it?
2. can be caused by what?
3. they occur when?
4. they occur more often where?
5. diff?

Answer 9

1. – a linear cleavage into the epidermis, extending sometimes into the dermis
2. disease processes or injury
3. when the skin is thick and inelastic and then subject to sudden swelling from inflammation or trauma
4. the ear margins, footpads, mucocutaneous junctions of the mouth and anus, and planum nasale.
5. The hyperkeratotic disorders of the footpads (mentioned on item g above) can be associated with fissures.