Equine Dermatology Flashcards
Horse presents with hair loss. The horse is pruritic and the client states that it has been getting worse since the end of Fall. Client noticed that another horse in the neighboring stall in their barn has similar signs, but not as severe. What is a likely diagnosis?
ectoparasites-Lice
why does lice get worse in the winter?
that is when the nits hatch
What are the two lice that are host specific to horses?
sucking louse- Haematopinus asini
biting louse- Damalinia equi
Which type of lice affects the mane and tail areas on a horse?
Haematopinus asini
Why, when treating lice, does topical pyrethrin need to be used repeatedly?
it does not affect the nits, so must wait for them to hatch to kill the lice
What other treatments may be used to treat lice infestations?
Ivermectin/moxidectin
fipronil
disinfect environment, too
What clinical signs are associate with mange in horses?
intense pruritus, crusting, exudation
What are two reportable types of mange and what area of the horse do they affect?
sarcoptic mange- head and neck
Psoroptic mange- mane and tail
What types of horses are predisposed to Chorioptic (leg) mange?
draft horses
What can be used to treat mange?
clip hair from feathers and pastern
ivermectin, moxidectin, topical pyrethrin
decontaminate premises
frontline
It is late summer and a horse presents with pruritus. Client said he noticed the horse's discomfort yesterday and went on a ride through tall prairie grasses the day before. On PE, you see wheals of orange, red, and yellow dots over the horse's limbs. What treatment would be best for this patient? A. Frontline B. ivermectin C. prednisolone D. clip hair and treat with flea shampoo
C
what time of the year are ticks more likely to cause problems with horses?
spring and summer
3yr old Horse presents in the summer with patchy alopecia of the head and ventral midline. Some affected areas have cutaneous ulceration. How to diagnose the problem in this case?
minced skin preparation yields microfilaria of Onchocerca
T/F: Culicoides hypersensitivity is a heritable condition
True
what is atopy?
inhaled allergen produces a cutaneous reaction
Horse presents in April with crusted, moist mats of hair along the dorsum. The skin is ulcerated and moist. There are patches of alopecia along the back and sides of the horse. What test would help to diagnose this case?
What is causing the problem in the horse with crusty, moist skin?
impression smear of the crust on the horse
Dermatophilus congolensis or rain scald
How to treat rain scald? (Dermatophilus congolensis)
bathe horse with clorhexidine, sedate horse if painful, and admin systemic penicillin.
What is the most common contagious skin disease of horses?
Ringworm
What type of lesion will help pinpoint you to a diagnosis of ringworm?
circumferential spread or bulls-eye lesion
What is the best way to definitely diagnose ringworm?
Biopsy
Best way to treat ringworm in horses: A. systemic antifungals B. OTC topical antifungal and disinfect potential fomites C.Ivermectin D. prednisolone
B
Pemphigus foliaceous is what type of hypersensitivity reaction? A. 1 B. 2 C. 3 D. 4
B. Type 2
Which animal has a better prognosis with pemphigus foliaceous- young animal or older animal?
Young animal
What are your top differentials for a distal limb dermatitis?
- bacterial pastern folliculitis
- scratches
- dew poisoning
- mud fever
- greasy heel
- rainscald, fungal, staph
What causes primary photosensitization? What organ, when affected, can cause secondary photosensitization?
primary- plants
second-liver
Hives is what type of hypersensitivity? A. 1 B. 2 C. 3 D. 4
A. Hives is a type 1 hypersensitivity
Horse presents with masses on the skin along the neck and withers. Doesnt seem to be painful or pruritic to the horse. The masses are small, haired, raised, and hard on palpation. What are these masses and how to treat?
Nodular necrobiosis intralesional triamcinolone (steroid)
What causes warts around the muzzle, eyes and ears in horses?
Papilloma virus
Is sporothrix schenckii zoonotic?
yes- can enter traumatic wounds
What are some adverse effects associated with iodide treatment in horses?
dry skin, tearing, coughing, abortion
Corynebacterium pseudotuberculosis lesions are (anechoic/hyperechoic) on ultrasound.
anechoic
What is the hallmark of pythiosis?
hard white to yellow gritty masses in draining tracts
what are your treatment options for pythiosis?
- surgical excision
- topical ketoconazole and DMSO
- regional antifungal therapy
What are the three types of sarcoid skin tumors?
flat/occult
verrucous
fibroblastic
What is the problem with treating sarcoids with Xxterra?
- not FDA approved
- may cause cosmetic issues (shrivel up the ear if lesion is on the ear)
What is a cosmetic problem with treating sarcoids with liquid nitrogen?
causes the hair to grow in white
What areas are affected by SCC?
eyes, vulva, prepuce
Firm, nodular, dermal, hairless black masses on a grey horse. What is the likely differential?
Melanoma
What causes depigmentation without trauma? What is it called when there is depigmentation due to trauma or disease?
w/o trauma- Vitiligo
w trauma/dz- Leukoderma
What is the name for the inherited disorder in QH resulting in a dorsal distribution of linear crusting lesions in a reticulated pattern?
Reticulated Leukotrichia
Horse has swelling over withers, draining tracts from the withers. What is this?
fistulous withers- bacti infection of supraspinous bursa
How to diagnose hyperelastosis cutis?
signalment and clinical signs, genetic testing
HERDA or hyperelastosis cutis
inherited autosomal recessive connective tissue disorder. It develops from a homozygous recessive mutation that weakens collagen fibers that allow the skin of the animal to stay connected to the rest of the animal. Affected horses have extremely fragile skin that tears easily and exhibits impaired healing. In horses with HC, the skin separates between the deep and superficial dermis. There is no cure. Most individuals receive an injury they cannot heal, and are euthanized. Managed breeding strategy is currently the only option for reducing the incidence of the disease.
sporothrix schenckii
a thermally dimorphic fungus that can be found world-wide. The species is present in soil, and in vital and decomposing plant material such as peat moss
Xxterra
a herbal formulation containing bloodroot powder and Zink chloride solution combined and stirred in to a smooth brown paste
The main ingredient is Bloodroot (Sanguinaria Canadensis), an herbal plant that grows abundantly in the southern parts of the United States. It contains the alkaloids sanguinarine, protopine, and chelarythrine, the most important being Sanguinarine. The plant was first used by Native Americans for skin conditions, and has been used since then.
Sarcoids
The term Sarcoid is used to describe various skin tumors in horses. Sarcoid comes in all sizes and shapes and general only affect the skin. Sarcoids can be benign but also malignant. Therefore veterinary advice should always be sought in cases of sarcoids.
