derm Flashcards

Question

plants and substances associated with photosensitazation

Answer 1

 Plants associated with hepatic photosensitization:  Lantana  Puncture vine  Mycotoxins  Plants with photodynamic substances:  St. John’s wort  Buckwheat  Spring parsley

Answer 2

 Contact Irritant Dermatitis  Direct damage caused by caustic chemicals  Systemically distributed chemicals:  Arsenic, mercury, thallium, iodine,  Plants: selenium, mimosine, trichothecenes lesions: Hyperkeratosis, squamous metaplasia

Answer 3

 Pathogenesis:  Ingestion of grain/seeds infected by Claviceps purpurea -> produce ergotamin -> arteriolar spasm and endothelial damage -> ischemia of distal extremities, tail etc.  Appetite, cardiovascular function, endocrine activity, gastrointestinal motility, muscle contraction, and temperature regulation (vasoconstriction)** -gangrene feet or fescue foot

Answer 4

 Tall fescue is infected with the fungal endophyte Neotyphodium coenophialum  The endophyte produces Ergot Alkaloids

Answer 5

 Injection site reactions (rabies vax alopecia) 3-6 months after vaccination** then hair growns back -ischemia and damage to hair follices, panniculitis -usually self harm diseases from atopy or allergic reactions

Answer 6

 Hyperkeratosis, acanthosis,  lick granulation tissue and fibrosis -common, usually has underying cause, food allergies or skin damage. -lesions: circumscribed, hairless, erythamtous, ulcerated.

Answer 7

-moist crusty lesion -common in dogs  Occur secondary to licking and scratching  Usu. Underlying diseases -self inflicted trauma, biting, pain gross: excudative, ulcerative, red egdes, alopecia.

Answer 8

 Cutaneous infections develop when there is disruption of dermal defense mechanisms  Physical barrier (hair coat, pigment, desquamation of stratum corneum)  Chemical and biochemical barrier (lipids, transferrin, antimicrobial substances)  Biologic barrier (microbial flora)  Innate immunity (transferrin, antimicrobial substances, defensins)  Acquired immunity (antibodies, lymphocytes)

Answer 9

 Parapoxvirus  young sheep and goats  High morbidity and low mortality  Lesions: proliferative, crusting dermatitis  Mouth -> oral mucosa, eyelids, and feet  $$ weight loss in lambs  Zoonosis possible (milkers nodules)

Answer 10

 GAIN access through defects in epithelium  ENTER basal layer  3 outcomes: 1. Virus DNA replicates with cells. 2. Virus converts from latent to productive 3. Virus is integrated into the genome -> tumor  Exophytic or endophytic papillary benign masses  Sarcoids = fibropapillomas (particularly in equids)  Bovine papillomavirus 1 and 2 infection of fibroblasts  Frequently recur, may regress, locally aggressive (non-metastatic)

Answer 11

-greasy pig disease -caused by staphlococcus hysius -neutrophillic pustules that develop into crusts in pigs and dogs -acute often FATAL dermatitis of neonatal piglets, mild in older piglets

Answer 12

-deep bacterial infections involve the entire infundibular, isthmic and/or inferior portion of the hair follicles +/- surrounding dermis and subcutis.  Less common than superficial pyoderma causes:  S. pseudointermedius folliculitis/furunculosis in dogs  Cat fight abscesses  Often secondary

Answer 13

-caused by Mycobacterium lepraemurium  Cold, wet areas – PACIFIC NORTHWEST (USA/CA) BC and washington  PCR test only  Gross: Head, neck and limbs – SQ nodules and crusts  Histo: two patterns 1. diffuse granulomatous w/o necrosis, many intrahistiocytic acid fast bacilli 2. granulomas with central necrosis, surrounded by lymphocytes, few acid fast bacilli

Answer 14

 Secondary to systemic bacterial infections, usually in finisher pigs 12 weeks of age.  Erysipelothrix rhusiopathiae (“diamond skin disease”) due to rhomboid shaped skin lesions  Vasculitis, thrombosis and ischemia (infarction) central of single BV morph: dermal and epidermal infarctions

Answer 15

 Pathogenesis:  Trauma & moisture + Bacteroides nodosus and Fusobacterium necrophorum  B. nodosus produces potent proteolytic enzymes  F. necrophorum is predominantly responsible for necrosis resulting in separation and sloughing of hooves

Answer 16

-associated with prolonged wet skin, keep dry for treatment. -ZOONOTIC on fingers -horses and cattle, usually young. sheep= lumpy wool -lesions: crusts with matted hair over back and distal extremitires. paint brush on pulled hair

Answer 17

-RINGWORM: caused by mycrosporum canis/ trichophyton.  Love the Stratum Corneum layer and Hair Shafts  DO NOT have to enter the living skin tissue to cause disease  ZOONOTIC  Asymptomatic cats – Toothbrush technique

Answer 18

-malassia pachydermatis -lipophilic yeast normal in ear canal and skin lesions: hyperpigmented, alopecic, scaly  Microclimate or host defenses changed  Mostly interdigital, otic, perianal, and intertriginous (spots that rub)

Answer 19

-demodex canis: demodectosis. in juvenile dogs from the dam. they have underlying disease causing immune suppression. -localized ( face or forlegs )or generalized scaling. not pruritic unless pyoderma. -deep skin scraping -sarcoptic mange (zoonosis) dogs and cats. extreme puritis -cheyketiella (walking mange) looks like dandruff on fur -chortoptic mange (cattle)

Answer 20

-pediculosis -from biting or sucking lice, whole cycle on host

Answer 21

-larval infestation by dipterous flies -blow flies and fresh flies -eggs on wounds-> larve secrete enzymes-> holes and ulcerated skin. -cuterebra sp. (kittens) -screwworm in cattle $$

Answer 22

 New world = Cochliomyia hominivorax  Old world = Chrysomyia bezziana  Tropical climates  Screwworm flies deposit eggs in wounds or near mucocutaneous junctions -> develop into L1 and feed on tissue -> soon develop into L2 -regulatory pest

Answer 23

 Habronema or Draschia sp. larvae  Skin that is traumatized or moist.  Medial canthus of eye or prepuce.  Unable to penetrate normal skin -horse disease on mouth or penis

Answer 24

* Hypersensitivity: reaction to normally harmless foreign substances. – Most are type I and IV reactions in skin – Common in dogs and horses – Less common in cats, uncommon in FA * Autoimmune: antibodies or T lymphocytes react against self-antigens. – Tend to be type II and III.** – Cutaneously manifested autoimmune diseases are uncommon in domestic animals.

Answer 25

* Urticaria = hives: edema of the superficial dermis * Angioedema: edema of the deep dermis and subcutis * Most common in dogs and horses * Causes: – Immunologic: foods, drugs, antisera, insects – Non-immunologic: heat, stress, exercise

Answer 26

-Genetically predisposed** inflammatory and pruritic allergic skin disease * Type I hypersensitivity** * Average age of onset is from 1 to 3 years  Skin is the major target organ in dogs, cats, and horses  Route of allergen exposure could be respiratory or skin  It is suspected to be predominantly percutaneous absorption of allergens -2nd most hypersens in dogs -lesions: rubbing, PURITIS, alopecia. do allergen test

Answer 27

Mixed type I and type IV: Cutaneous basophil hypersensitivity * Dogs and cats * Pruritic papular dermatitis -> self-inflicted trauma and chronic lichenification (thickening of skin) * Fibropruritic nodules: core of collagen covered by a hyperplastic epidermis

Answer 28

* Type I hypersensitivity – Intradermal skin tests – Prausnitz-Kustner tests * Primarily on the external nose -> nasal planum, periocular skin, pinnae and less commonly foot pads. * Erythematous papules ->crusts, ulcers, alopecia * Hypopigmentation or hyperpigmentation

Answer 29

-common and misdiagnosed  Frequent skin and ear infections.  May also present with vomiting and diarrhea.  Similar presentation to Atopy, at any age  Need to do a strict elimination trial to determine the foods animals are allergic to diagnose  (ELISA assay is not reliable predictor of these).

Answer 30

Type IV reaction:** – Haptens and cytotoxic T cells – Eosinophils are variable * Chemicals: aniline dyes in carpets, plant resins, chemicals in shampoos, plastic food dishes.** * Pruritus with self-inflicted trauma * Regions in contact with antigen. * Spongiotic superficial perivascular dermatitis, epidermal hyperplasia with varying numbers of eosinophils

Answer 31

 Gross: Transient vesicles or bullae  Histo: Acanthosis  Type II reaction**  Autoantibodies against proteins responsible for cell adhesion (desmosomes)  Damage to desmosomes ->acantholysis ->formation of bullae pemphigus folaceous: when vesicles become pustules --> secondary crusts and scales -dogs and cats: NOSE then ears, eyes, neck * Horse: subcorneal pustules * Dog: stratum spinosum pemphigus vulgaris:  Basal cells attached to basement membrane -> tombstoning  Mucocutaneous junctions  More severe than PF -rare, oral skin.

Answer 32

 Type III response**  Defective T cell suppressor and cytokine disregulation  Immune complexes formed and deposited in skin  Basal cell or keratinocyte degeneration -dogs, cats, horses: uncommon. look for in the nose. lichenoid inflammation

Answer 33

-cats -self inflicted alopecia (forearms and bellys) -rough appearance, thin

Answer 34

 The most common endocrine dermatosis in dogs  Age: over 6 years  Intolerance to cold  Obesity  Hair coat dry, dull, coarse, sparse  Alopecia  Adnexal atrophy  Dermal edema  Hyperpigmentation  Scaling

Answer 35

Cortisol excess:  Adnexal atrophy ->alopecia  Fibroblasts inhibited -> thin skin  Hepatic glycogen -> hepatomegaly  Collagen/elastin change -> dystrophic calcification (calcinosis cutis)  Immunosuppression -> infections Causes:  Pituitary (85-90% of dogs)  Adrenocortical (10-15% of dogs)  Iatrogenic  The second most common endocrine dermatosis in dogs

Answer 36

 Males and females  Sertoli cell tumor (cryptorchid)  Ovarian cysts  Atrophied hair follicles -swollen vulva in females gross looks like hypothyroid skin

Answer 37

 Dogs with normally PLUSH hair coats, 1-2 years old  The head and distal extremities are often spared of alopecia  Normal thyroid and glucocorticoid levels  Skin biopsy samples with telogen follicles (retained hair shafts and flame follicles) -permanent disease, neutering may work. some dogs respond to melatonin

Answer 38

-chronic disease complex secondary to abnormalities of the sebasceous glands associated with a change from bacteria to pathogenic.  Seborrhea Sicca - Dry form  Dry skin and white-gray scales.  Seborrhea Oleosa - Greasy form  Scaling and excessive brown to yellow lipids that adhere to the skin and hair. -primary ideopathic is most common -secondary with inflammation

Answer 39

 Cattle and dogs  Scaly, cracked skin -ichytosis fetalis - FATAL, congenital fetal disorder,

Answer 40

 Dogs (pigs)  Lesions: scaling and crusting with marked diffuse parakeratosis** eyes and nose  Pathogenesis: Inherited reduced ability to absorb Zn from the intestine (Alaskan Malamute and Siberian husky) Large breed, rapidly growing pups – low zinc diets. they need zinc supplaments

Answer 41

 Eosinophilic plaques:  Common in cats  Possible link to hypersensitivity reactions  Eosinophilic granulomas:  Horses, dogs and cats  Flame figures, eosinophil degranulation  Lesions: nodular dermatitis, indolent ulcers

Answer 42

 Puppy strangles  No microorganism identified (sterile lesions)  Secondary bacterial infections  Lesions: pustular and nodular dermatitis with edema (facial mostly)

Answer 43

-squamous cell carcinoma (cats* nose) -histocytoma (common), regress on their own -lipoma (cut open, hide Mast cell tumor. boxers**) -injection site fibrosarcoma (FLV, rabies) -basal cell tumors -sebaceous gland hyperplasia