Papules, Pustules, & Crusts

Question 1

Papule (3)

Answer 1

1) small solid elevation
2) up to 1 cm
3) due to infiltration of inflammatory cells & edema

Question 2

Flea bite hypersensitivity*** clinical signs (6)

Answer 2

1) pruritus
2) erythema
3) excoriation
4) self induced alopecia
5) crusted papules
6) dorsal lumbar region most affected

Question 3

Sarcoptic mange (scabies)** clinical signs (7)

Answer 3

1) INTENSE pruritus
2) excoriation
3) crusts
4) self induced alopecia
5) papules
6) lateral surfaces of the skin (hock, elbows, ventral abdomen)
7) alopecia and crusting of the margin of the pinna

Question 4

Miliary dermatitis (crusted papular dermatitis) ** (1)

Answer 4

1) not a disease but a cutaneous reaction pattern associated with hypersensitivity in cats (allergies)

Question 5

Pustules &/or Crust classification (3)

Answer 5

1) Infectious: bacterial superficial pyoderma***
2) Autoimmune: pemphigus foliaceus *
3) sterile

Question 6

Superficial pyoderma (2)

Answer 6

1) common in dogs
2) staphylococcus pseudintermedius & staphylococcus schleiferi

Question 7

Bacterial folliculitis*** (5)

Answer 7

1) extremely common in dogs, rare in cats
2) superficial pyoderma that affects the follicles
3) regions effected: abdomen, groin, medial thighs, axilla
4) pruritus variable
5) crusts are small

Question 8

Bacterial folliculitis*** of short coated breeds (5)

Answer 8

1)extremely common in dogs, rare in cats
2) spontaneous alopecia
3) multifocal do not tent to expand & coalesce
4) affected areas; trunk, extremities (lateral & medial aspects
5) commonly mistaken as dermatophytosis

Question 9

Bacterial impetigo (4)

Answer 9

1) puppy pyoderma
2) causes by certain strains of staphylococci that produce exfoliative toxins
3) affected region: abdomen
4) flaccid pustule that leads to epidermal collarettes that don’t coalesce/expand

Question 10

Exfoliative superficial pyoderma *** (4)

Answer 10

1) lesions: large rapidly expanding epidermal collarettes, peripheral erythema, hyperpigmented center in chronic lesion
2) pustules RARELY seen)
3) pruritus variable
4) bacterial exfoliative toxins that separate the stratum corneum

Question 11

Cytologic diagnosis of bacterial folliculitis (2)

Answer 11

1) sampling: intact pustules, beneath the crust
2) cytology: degenerate neutrophils with intracellular bacteria

Question 12

Cytologic diagnosis of bacterial folliculitis of short coated breeds (1)

Answer 12

1) cytology may not yield degenerate neutrophils or bacteria, if it does very scant

Question 13

Cytologic diagnosis of bacterial impetigo (2)

Answer 13

1) Sampling: intact pustules, edge of epidermal collarette
2) cytology: degenerative neutrophils with intracellular cocci, free floating epidermal cells due to separation of the stratum corneum

Question 14

Cytologic diagnosis of exfoliative superficial pyoderma (2)

Answer 14

1) sampling: edge of epidermal collarette
2) cytology: similar to bacterial impetigo but presence of bacteria usually very scant

Question 15

Treatment of localized superficial pyoderma (7)

Answer 15

1) topical antibacterial
2) chlorhexidine
3) benzoyl peroxide
4) dilute bleach (1:100)
5) mupirocin
6) gentamicin
7) erythromycin

Question 16

Treatment of widespread superficial pyoderma (1)

Answer 16

1) oral/systemic antibiotics

Question 17

What antibiotics should we NOT use in treating superficial pyodermas & why? (2)

Answer 17

1) Penicillin, amoxicillin & ampicillin
2) S. pseudintermedius & S. aureus produce beta lactamase destroys these drugs

Question 18

How long should we treat using oral antibiotics? (1)

Answer 18

1) 3 weeks or 1 week beyond clinical resolution

Question 19

When should fluoroquinolones be used? (1)

Answer 19

1) reserved for infections that did not respond to previous antibiotics OR whenever bacterial resistance is demonstrated

Question 20

Pemphigus foliaceus * (2)

Answer 20

1) most common autoimmune skin disease in dogs and cats
2) autoantiboidies target desmosomes in the superficial epidermis

Question 21

Pemphigus foliaceus * distribution of skin lesions (4)

Answer 21

1) facial: nasal planum, nose bridge, periorbital, pinnae
2) bilateral symmetrical
3) concave and convex pinna
4) footpads

Question 22

Pemphigus foliaceus diagnosis (3)

Answer 22

1) superficial pyoderma MUST be ruled out first
2) cytology: nondegenerate neutrophils with acantholytic keratinocytes, no bacteria
3) biopsy: intact pustule or lesion with crust, diagnostic

Question 23

Treatment of pemphigus foliaceus (2)

Answer 23

1) oral glucocorticoids- if this fails to control disease in 4-6 weeks proceed to step 2
2) oral glucocorticoids + azathioprine- after 4-6 weeks stop steroid and assess if azathioprine monotherapy then taper azathioprine to lowest possible dose