L2-Physical/ Chemical injury, nutritional endocrine and hypsensitivity disorders

Question 1

Pyotraumatic dermatitis

Answer 1

hot spot- physical injury
-complication of allergic dermatitis
-breeds with thick undercoat are predisposed
CONSTANT SELF TRAUMA, PAINFUL LESIONS
sharply demarcated areas of alopecia with exudate and ulceration
injection site reaction
due to REACTION TO ADJUVANT (RABIES)
dermal nodule

Question 2

Psychogenic alopecia

Answer 2

cats, exacerbated by stress

Question 3

Acral lick dermatits

Answer 3

lick granuloma-dogs
large active-breed dogs
persistant licking and chewing
distal extremities

Question 4

Thermal injury

Answer 4

liquids, fire, electrical wires, hot metals, hot blankets, lightning strike
can take time to fully see lesion extent 24-48hrs
Death often due to severe protein/fluid loss and secondary infections
dry heat- desiccation
moist heat- boiling and coagulation

Question 5

First degree thermal injury

Answer 5

only involve epidermis no vesicles or blisters, erythematous area

Question 6

second degree thermal injury

Answer 6

epidermis, superficial dermis affected
vesicles and bulla in epidermis

Question 7

third degree thermal injury

Answer 7

full thickness through epidermis and dermis
coagulative necrosis, thrombosis of vessels

Question 8

Fourth degree thermal injury

Answer 8

similar to third degree, but penetrates into subQ tissues and beyond

Question 9

Thermal injury classification

Answer 9

Question 10

Radiation acute injury

Answer 10

damage to rapidly dividing cells
lesions appear 2-4 weeks after exposure
erythema, edema- desquamation
alopecia due to damage to hair follicles
sebaceous glands damaged- will have scaling

Question 11

Chronic radiation injury

Answer 11

months to years after treatment
damage to microvasculature
thin epidermis, hyperkeratosis and hyperpigmentation, chronic ulcers may devlop
dermis thickened with fibrosis

Question 12

primary contact dermatitis

Answer 12

contact with substance that causes direct damage
does not involve prior sensitization
erythema, swelling, papules- location depends on toxin application

Question 13

venom- spiders, snakes, bees, wasps

Answer 13

swelling/ edema, hemorrhage, necrosis, sloughing of tissue
brown recluse spider- dermonecrosis and eschar formation
snakes- crotalines- rattlesnakes, copperheads, cottonmouths, have most toxic venom
head and legs usually affected

Question 14

mineralization in tissues
Dystrophic

Answer 14

secondary to injury, inflammation, degeneration
often localized

Question 15

mineralization in tissues/Metastatic

Answer 15

secondary to systemic calcium/ phosphorus disturbance
chronic renal failure, hyperparathyroidism, hypercalcemia of malignancy
multiple tissues can be effected

Question 16

Cutaneous mineralization

Answer 16

Calcinosis cutis
dystrophic mineral
associated with hyperadrenocorticism or cushings disease
mineral within dermis

Question 17

Calcinosis circumscripta

Answer 17

tumoral calcinosis-pathogenesis unknown
large breed, young dogs, GSD predisposed
skin over bony prominences
bulging mass, contains chalky white material in deep dermis

Question 18

Heavy metal toxicity/Thallium toxicity

Answer 18

similar pharmacologic actions to lead and mercury
acute exposure- severe GI irritation, motor issues
chronic exposure- marked erythema, scaling, alopecia, crusting
start at commissures of lips and expand over head and face
massive parakeratotic hyperkeratosis
diagnostic sampling- thalium in urine or stomach contents

Question 19

Heavy metal toxicity/Selenium

Answer 19

occurs in grazing animals- skin lesions can take months to devlop
ingestion of selenium-accumulating plants- astragalus oxytropis
history of new herds to field with toxic plants, or fields with very little feeds
cattle and horses- alopecia, rough hair coat
lose hairs of mane and tail
hooves- coronary band lesions, dystrophic grooves, cracks, corrugations parallel to coronary band

Question 20

Mycotoxicosis/Ergotism

Answer 20

-claviceps purpurea in seeds of grasses and grains
-toxic alkaloids cause diseases

Question 21

Mycotoxicosis/Fescue

Answer 21

Tall fescue grass with fungus Neotyphodium coenophialum
- Toxic alkaloids cause disease not the fungus itself
- most common in cattle
MARKED PERIPHERAL VASOCONSTRICTION
thrombosis and ischemic necrosis of tissues
Distal extremities
can lead to SLOUGHING OF HOOVES

Question 22

Hairy Vetch toxicity

Answer 22

VISCIA VILLOSA ROTH
-legume often found in feed or pasture
-not all animals with have clinical signs
- likely due to prussic acid, but unknown pathogenesis

3 syndromes
- acute neurologic-fatal
systemic disease- subQ swelling, bronchitis-fatal
SYSTEMIC GRANULOMATOUS DISEASE- most common crusting, alopecia, lichenification/thickening, pruritic
Biopsy- DX of exlusion
rule out fungal, mycobacterium

Question 23

Actinic or solar dermatitis

Answer 23

• sunburn
• mainly in cats, dogs, pig, cows and goats
  LIGHT COLORED ANIMALS
• cats/ white- blue eyed animals
  tips of ears, nose, eyelids, lips
• erythema, crusting, alopecia
• CAN PROGRESS TO SQUAMOUS CELL CARCINOMA

Question 24

photosensitization

Answer 24

• occurs when PHOTODYNAMIC PIGMENTS ARE DEPOSITED IN SUNLIGHT-EXPOSED SKIN
• plant pigments, drugs, byproducts of hemoglobin metabolism, chlorophyll degradation products
• pigments usually ingested from plants
• see lesions in grazing animals
  LESIONS ON SKIN EXPOSED TO SUN, ESPECIALLY LIGHT- COLORED SKIN
  erythema, edema, exudate, necrosis, sloughing
• very pruritic

Question 25

Photosensitization types

Answer 25

type I: direct ingestion ( primary hypersensitivity) of plants with pigments- st. johns wort and buckwheat, moldy cooperia- hill country rain lilly type II: defective heme synthesis- rbc production - uroporphyrin by- product accumulation - congenital defect- causes porphyria- not common type III: damaged liver- most common- ingest plant plus liver damage most common form in domestic species damaged liver- unable to secrete phylloerthrin toxic plants: lantana, trifolium, panicum grass

Question 26

ENDOCRINE: general lesions with endocrine disease

Answer 26

skin manifestations not unique to on specific disease include BILATERALLY SYMMETRICAL ALOPECIA dry, dull, brittle hair coat hyperpigmentation

Question 27

endocrine/Hypothyroidism

Answer 27

most common endocrinopathy in dogs usually middle aged dogs thyroid hormone TH needed for hair follicle growth, regulates sebum from sebocytes seborrhea, dry brittle hair, hyperpigmentation, comedones bilaterally symmetrical alopecia elbows, hocks, hips, neck ( collar) entire tail diagnostics: low T4, low free T4, high TSH

Question 28

endocrine/ hyperadrenocorticism

Answer 28

cushings disease middle aged to older dogs due to tumor in pituitary gland, tumor in adrenal gland, iatrogenic BILATERALLY SYMMETRICAL ALOPECIA ALONG TRUNK, THIN PENDULOUS ABDOMEN, hyperpigmtation calcinosis cutis diagnostics: ACTH stim or LDDS test

Question 29

endocrine/ PPID pituitary pars intermedia dysfunction

Answer 29

- horses due to tumor in the pituitary gland coarse, long shaggy hair coat that doesnt shed (hirsutism), sweating also associated with laminitis and rotation of P3

Question 30

endocrine/ hyperestrogenism

Answer 30

excess estrogen production dogs: male dogs with sertoli cell tumor female with ovarian neoplasms or pcos symmetrical alopecia perineum and genital region- trunk Ferret- associated with adrenal tumor bilateral symmetric alopecia vulvar enlargement

Question 31

endocrine/ alopecia X

Answer 31

dogs- usually plush- coated breeds pomeranians, husky, malamute, chows normal thyroid and adrenal function- unknown pathogenesis symmetrical alopecia of trunk, caudal thighs, perineum, neck ( head and limbs not involved) hyperpigmentation of exposed skin NON- PRURITIC

Question 32

endocrine/ canine recurrent flank alopecia

Answer 32

usually short coated dog breeds- boxers, bulldogs bilaterally symmetrical alopecia of the flank very well demarcated, underlying skin usually hyper pigmented recurrent or seasonal NON PRURITIC

Question 33

hypersensitivity/ Type I

Answer 33

Type I: immediate, targets allergens, anaphylaxis vascular dilation, edema, inflammation

Question 34

hypersensitivity/ Type II

Answer 34

Type II: antibody mediated, targets cellular antigens - cell lysis and inflammation

Question 35

hypersensitivity/ TYPE III

Answer 35

Type III immune complex mediated, targets soluble antigens vasculitis, inflammation

Question 36

hypersensitivity/ Type IV

Answer 36

TYPE IV: DELAYED. cell mediated T, targets about any antigen edema, cell lysis, granulomas

Question 37

Atopic dermatitis

Answer 37

allergic skin disease- inflammatory and pruritic common in dogs young dogs less than 3 yr old can occur in cats main clinical sign is (PRURITUS) may be seasonal and progress to year round responds excellent to steriods

Question 38

Atopic dermatitis

Answer 38

5 Fs: face, feet, folds, flexures, friction diagnosis: young dog, indoor living, pruritus prior to lesions, front paws and inner pinna affected rule out FAD and other mites PRURITUS AND ERYTHEMA excoriations, ulceration, papules due to self trauma can lead to hot spots

Question 39

cutaneous adverse food reaction

Answer 39

occurs in dogs, rarer in cats allergen: food protein- beef, chicken, milk, eggs, wheat nonseasonal pruritus tends to respond poorly to steriods distribution very similar to atopic dermatitis 5 Fs: face, feet, fold, flexures, friction diagnostic: food trial

Question 40

Urticaria

Answer 40

hives/wheals, heat bumps very common in horses last up to 24 hours, then go away lots of causes: food, drugs, insect bites, contact allergens, infections increased vascular permeability from histamine- edema leaks out discrete, well circumscribes, edematous, plaques with flat top

Question 41

insect hypersensitvity

Answer 41

venom, saliva, skin, capsule, feces tend to be seasonal pruritic papules with crusting, thinly haired areas more effected flea allergy dermatitis: ctenocephalides felis most common allergic dermatosis of dogs and cats alopecia, lichenification, hyperpigmentation over RUMP AND CAUDAL THIGHS very pruritic- often have self trauma in cats, miliary dermatitis with small papules

Question 42

Insect hypersensitivity

Answer 42

Culicoides: hypersensitivity in horses most common allergy queensland itch, summer itch, summer eczema very pruritic- head, neck, ears, back and tailhead papules that can becomes excoriations, crust, alopecia