Equine Dermatology

Question 1

Equine Folliculitis and Furunculosis

Answer 1

Secondary to cutaneous trauma and stress
In areas of contact with tack, blankets, abrasive surfaces or rider
Poorly groomed horses @ risk

Question 2

Folliculitis

Answer 2

Inflammation with or without infection of hair follicles
Rupture of the hair follicles

Question 3

Furunculosis

Answer 3

Inflamm. process breaks through the hair follicles and extends to surrounding dermis and subcitus

Question 4

Carbuncle (boil)

Answer 4

Multiple areas of furunculosis coalesce

Question 5

Lesions of Equine Folliculitis and Furunculosis

Answer 5

Superficial lesions of folliculitis are asymptomatic
Deep lesions of furunculosis painful

Question 6

Pastern Folliculitis and Furunculosis

Answer 6

Restricted to caudal aspect of the pastern and fetlock regions
Coalescent areas of alopecia, exudation and crusting

Question 7

Most common bacteria associated with Equine Folliculitis and Furunculosis

Answer 7

S. aureus or pseudointermedius

Question 8

Equine Dermatophilosis

Answer 8

Infectious, superficial pustular and crusting dermatitis caused by D. congolensis (contagious)
Rain rot, rain scald or mud fever
Skin damage and moisture

Question 9

Where is Equine Dermatophilosis found?

Answer 9

Rump and topline, saddle area, face and neck, pasterns, coronets and heels
White-skinned areas

Question 10

Tx of Dermatophilosis

Answer 10

Spontaneous regression within 4w
Keep animals dry, crust removal
Topical tx (lime sulfur, etc.)
Systemic therapy (penicillin, etc.)

Question 11

Cause of Dermatophilosis

Answer 11

Moisture causes release of the zoospore (attracted to low concentrations of CO2, repelled by high concentrations)

Question 12

Lesions of Dermatophilosis

Answer 12

Follicular and non-follicular tufted papules, pustules, groups of matted hair (paintbrush effect)

Question 13

Equine Corynebacterium pseudotuberculosis

Answer 13

Causes deep SQ abscesses
Bastard strangles, pigeon breast
Spread by biting flies (horn flies)

Question 14

What are the biotypes of Corynebacterium pseudotuberculosis

Answer 14

Sheep and goat isolated nitrate-negative
Horses and cattle nitrate-positive

Question 15

When do lesions of Corynebacterium pseudotuberculosis occur?

Answer 15

50% in pectoral and ventral abdominal areas
Thorax, neck and head
Late summer, fall and early winter

Question 16

CS of Corynebacterium pseudotuberculosis

Answer 16

Pitting edema, ventral midline dermatitis, depression, fever and lameness
Pupura hemorrhagica sequela to long-standing cases

Question 17

Dx Corynebacterium pseudotuberculosis

Answer 17

History, CS, direct smears and cx
Small G+ rods with chinese letter appearance

Question 18

Corynebacterium pseudotuberculosis Tx

Answer 18

Draining and incising the abscesses
^ if no, procain penicillin

Question 19

Large animal dermatophyosis

Answer 19

Microsporum and trichophyton
T. equinum, mentagrophytes and M gypseum in horse
T. verrucosum in cow, sheep and goat
M, nanum in pig
Direct and indirect contact

Question 20

Geophilic Large animal dermatophyosis

Answer 20

M. gypseum, M. nanum and T. ajelloi inhabit the soil

Question 21

Zoophili Large animal dermatophyosis

Answer 21

M. canis, T. equinum adapted to animals

Question 22

Anthropophilic Large animal dermatophyosis

Answer 22

M. audouinii adapted to humans, won’t survive in soil

Question 23

Where is Large animal dermatophyosis common?

Answer 23

Cattle, horses, goats and swine (not sheep)
Most common in <1y

Question 24

Main sources of immunity to dermatophytes

Answer 24

Cell-mediated immunity and delayed-type hypersensitivity rx

Question 25

Lesions of Large animal dermatophyosis

Answer 25

Annular area of alopecia, stubbled hair, crusting and dermatitis
Folliculitis and furunculosis common (papules, ulcers, nodules, sinuses)
Kerion (nodular, boggy, pus)

Question 26

Tx for Large animal dermatophyosis

Answer 26

Lime sulfur, captan, sodium hypochlorite and iodophors
Griseofulvin, thiaendazole