Integumentary Pathology Flashcards
7 steps of regeneration & repair of the skin
Blood clot, inflammation, re-epitheilization, fibroplasia, angiogenesis, wound contraction, remodeling
Hallmark of wound healing
granulation tissue
2 responses of the EPIDERMIS to injury
Alteration in growth & differentiation
Alteration in fluid balance & cellular adhesion
3 forms of alterations in epidermal pigmentation
Hyperpigmentation
Hypopigmentation
Pigmentary incontinence
2 dzs that lead to increased production of melanin
allergic dermatitis
Hyperadrenocorticism (Cushing’s)
2 dzs. that lead to increased melanocytes
Lentigo
Melanocytic Neoplasia
What mineral deficiency can result in HYPOpigmentation
Cu deficiency = Acquired lack of melanin production
3 causes of DERMAL atrophy
Starvation
Cushing’s
Iatrogenic (long term steroid use)
What is the early stage of fibroplasia in response to injury?
Granulation tissue
What is another term for exuberant granulation tissue?
Proud flesh
What is the condition that is an inherited abnormality of collagen that results in increased stretchability? Give an example
Collagen Dysplasia
Cutaneous Asthenia
What are the 3 abnormal deposits in the dermis?
Amyloid
Mucin/Hyaluronic acid
Ca
What abnormal deposit in the dermis leads to cutaneous myxedema?
Mucin or hyaluronic acid (GAG)
When can you see cutaneous myxedema? (TQ)
HYPOthyroidism
Mucinosis of the Shar-Pei
3 forms of abnormal mineralization/calicification of the dermis
Dystrophic
Metastatic
Idiopathic
Dystropic mineralization is the result of chronic injury. Give 2 examples.
Calcinosis cutis
Granulomatous foci
Which form of mineralization results in deposition of Ca in tissues during hypercalcemia?
Metastatic
chronic renal dz, hyperparathyroidism, cholecalciferol toxicosis & calcinogenic plants
What are the characteristics of ACUTE dermatitis?
lasts hrs- several d.
Mostly neutrophils
What are the characteristics of CHRONIC dermatitis?
lasts wks, mo., yrs.
Mostly mononuclear leukocytes (macrophages, lymphocytes & plasma cells)
Acral lick dermatitis if what form of dermatitis?
Chronic
What 4 things can cause ATROPHY of the adnexa?
- hormonal abnormalities
- Nutritional abnormalities
- Ischemia
- Stress/poor health
What 4 things can cause HYPERTROPHY of the adnexa?
- injury
- Acral lick dermatitis
- Chronic allergic dermatitis
- Chronic bacT/yeast infections
What frequently causes alopecia?
follicular dysplasia
What often leads to abnormalities of hair cycle stages?
Hormonal disorders
Folliculitis is commonly seen with what 2 dzs?
Demodicosis
Pemphigus Foliaceus
What organisms can cause luminal folliculitis?
Staph.
Microsporum
Trichophyton
Demodex
Bulbitis is also called _____.
Alopecia areata
Sebaceous adenitis is most common in what species?
Dogs
Which form of adenitis is characterized by inflammation of the APOCRINE glands?
Hiradenitis
Which species are most commonly affected by vasculitis?
Dogs & horses
List some examples of dzs that can cause vasculitis.
SLE Rickettsia infections Herpesvirus FIP virus Erysipelothrix spp.
Black Diamond Skin Disease is a common name for what dz?(TQ)
Porcine Erysipelas (lesions due to vasculitis)
What are some causes of Panniculitis?
BacT & fungi SLE Physical injury Vit E deficiency Pancreatic dz. Idiopathic
What are the C.S. of Panniculitis?
painful, palpable nodules –> ulcerated & drain
Pyrexia
Lethargy
Inappetence
What are the 2 non-genetic forms of congenital alopecia & hypotrichosis?
Maternal Iodine deficiency
In Utero- Pestivirus infection (BVD & CSF)
What are the congenital & hereditary skin dzs? (7)
Congenital alopecia & hypotrichosis Collagen Dysplasia disorders Mucinosis Epidermolysis bullosa Epitheliogenesis imperfecta Congenital hypertrichosis Dermal Vegetans
Epidermolysis bullosa (red foot dz) is reported in what animal species?
horses, cattle, sheep, dogs & cats
Border dz or hairy shaker dz is an example of which congenital skin dz?
Congenital HYPERtrichosis due to in utero Pestivirus infection
Which breed of swine is Dermatosis vegetans common in?(TQ)
Landrace pigs (autosomal recessive trait)
What causes actinic injury on non-haired & non-pigmented areas?
UV radiation –> DNA damage (thymidine dimers) –> SCC
How does photosensitization occur?
photodynamic compounds react w/ UV radiation & cause oxidative injury
What is Type I Photosensitization?
caused by ingestion of certain plants or drugs
What is Type II Photosensitization?
Inherited defect in porphyrin metabolism
What is Type III Photosensitization (most common form)?
Hepatogenous photosensitization –> due to liver dz. & reduced ability to excrete phylloerythrin (by-product of chlorophyll metabolism)
What are the 2 causes of actinic injury?
Photosensitization
Photo-enhanced dermatoses
What dzs are associated w/ photo-enhanced dermatoses? (3)
Lupus erythematosus
Dermatomyositis
Photoactivated vasculitis of the horse
Where does photoactivated vasculitis often occur on the horse?
animals with white legs
Which species are prone to vaccine-associated sarcomas?
Felines
What does Ergot poisoning cause in animals?
ischemic necrosis of extremities
Which form of grass can get infected with Neotyphodium spp & contains ergot alkaloids?
tall fescue grass
What are the signs of Selenium toxicity in animals?
Poor hair coat w/ partial alopecia
What are the sings of Hairy Vetch toxicity in animals?(TQ)
dermatitis, conjunctivitis, diarrhea, granulomatus inflammation of many organs
What are the proper names for “hot spots”?
Pyotraumatic dermatitis
Acute mosit dermatitis
What physical injury is caused by psychological disorders that lead to persistent licking/chewing?
Acral lick dermatitis
Lick Granuloma
Neurodermatitis
Which animals are susceptible to intertrigo (skin fold dermatitis)?
Dogs- excessive skin folds
Cows- large pendulous udders
What are the 6 types of physical injury that can occur to the skin?
Acral lick dermatitis Pyotraumatic dermatitis Intertrigo Feline Ulcerative Dermatitis Syndrome Callus Temperature extremes
1st degree burns affect what layer of skin?
epidermis only
2nd degree burns affect what part of skin.
epidermis & part of dermis
3rd degree burns causes:
full thickness necrosis of skin
Permanent scarring
life threatening–> infection & fluid loss
Hypothyroidism affects what stages of the hair cycle in dogs?
Anagen stage; hair coat fails to grow
Hyperadrenocorticism has a _____ effect on _____ synthesis & maintenance due to excess glucocorticoids.
inhibitory
collagen
What is a common skin sign of hyperadrenocorticism in dogs?
Clinical cutaneous lesions
Calcinosis cutis - dystrophic calcification
Pituitary tumors of the pars intermedia in older horses leads to what?
Hyperhidrosis (incr. sweating)
Hirsutism/hypertrichosis
What are the C.S. of hyperestrogenism?
symmetric alopecia
follicular hyperkeratosis
Enlarged nipples, prepuce & vulva
What causes hyperestrogenism in females?
ovarian cysts or tumors
What causes hyperestrogenism in males?
Functional Sertoli cell tumor
Urticaria is most common in what 2 species?
dogs
horses
What is the immunologic mechanism of urticaria?
Type I & Type III hypersensitivities
What 3 things can cause non-immunologic urticaria?
heat
exercise
stress
What species commonly get atopic dermatitis?
dogs
cats
horses
What is the immunologic mechanism of atopic dermatitis?
Type I hypersensitivity w/ IgE Abs to environmental allergens
What is the predominant sign of atopic dermatitis?
Pruritis w/ frequent excoriations & secondary bacT & yeast infection
What is the immunologic mechanism of insect bite hypersensitivity?
Type I & Type IV hypersensitivity rxn to insect saliva
What are the gross lesions of insect bite hypersensitivity?
papular to exudative dermatitis
Miliary dermatitis
Which species commonly get miliary dermatitis?
cats!
What species of insect causes Sweet Itch in horses?
Culicoides
What is the immunologic mechanism of Allergic Contact Dermatitis?
Type IV
Gross lesions of allergic contact dermatitis.
Erythema
Papules
Exudation in contact areas
What is the immunologic mechanism of drug hypersensitivies?
any of the types
What are the 6 autoimmune dzs of the skin?
Pemphigus foliaceus (PF) Pemphigus vulgaris (PV) Bullous pemphigoid (BP) Systemic Lupus Erythematosus (SLE) Discoid Lupus Erythematosus (DLE) Erythema Multiforme (EM)
Which form of pemphigus is milder & most common?
pemphigus foliaceus
What is another name for pemphigus foliaceus?
superficial pemphigus
What is the pathogenesis of Pemphigus foliaceus?
AutoAbs against Desmoglain 1 & acantholysis of superficial dermis
Gross lesions of Pemphigus foliaceus.
vesicles–> rapidly become pustules
May be localized on face & feet or generalized
What is the histologic lesion commonly seen w/ Pemphigus foliaceus?
acantholytic keratinocytes
What is the other name for Pemphigus vulgaris & is more severe?
Deep pemphigus
Pathogenesis of Pemphigus Vulgaris? (TQ)
AutoAbs against desmoglein 3 & acantholysis of deep dermis
Gross lesions associated w/ Pemphigus Vulgaris?
Vesiculo-ulcerative lesions (mucocutaneous jxns)
Histological lesions are seen w/ Pemphigus Vulgaris?
suprabasilar vesicles
Pustules
Acantholytic keratinocytes
“Tombstoning” of basal cells
Pathogenesis of bullous pemphigoid (BP)?
AutoAbs directed against hemidesmosomal proteins & subepidermal vesicle formation
Which animals get Bullos Pemphigoid?
horses
dogs
cats
Yucatan minipigs (awe!!!)
Gross lesions of Bullos Pemphigoid?
vesicles erosions ulcers crusts variable locations & severity
Histologic lesions of Bullos Pemphigoid.
Subepidermal vesicles & bullae
Pathogenesis of SLE in dogs?
Type III hypersensitivity –> multi systemic
immune-complex deposition & AutoAbs
What titer is raised in dogs w/ SLE & can be used as a DX aid? (TQ)
elevated anitnuclear Ab titer
ANA titer
Gross lesions of SLE?
erythema depigmentation alopecia scaling crusting ulceration lesions start on face & extend to the trunk & extremities
Discoid lupus erythematosus (DLE) only involves which organ?
skin
Gross lesions of DLE are located where?
nasal planum dorsal nose pinnae lips periocular areas
What is the ANA titer of DLE patients?
NEGATIVE ANA titer
What can DLE lesions be indistinguishable from? How do you DX it ?
Mucocutaneous pyoderma
responsiveness to TX
Gross lesions of erythema multiforme (EM)?
localized or generalize erythema & circular/linear erosions or ulcerations
Histologic lesions of erythma mulitforme (EM)?
Numerous apoptotic keratinocytes w/in multiple layers of the epidermis
What is the often life-threatening form of EM that can result in full thickness epidermal necrosis?
Toxic epidermal necrolysis (TEN)
Which form of Poxvirus is the most pathogenic?
Sheeppox & Goatpox (FAD)
Pathogenesis of Poxviruses.
proliferation & necrosis
2 dermatotropic herpesviruses
BHV-2: ulcerative mammilitis
BHV-4: mammary pustular dermatitis
Vesicular-ulcerative dermatitis is a common lesion of _____.
Herpesviruses
What are the 2 oncogenic herpesviruses that cause cutaneous tumors?
Marek’s dz of chickens
Sea turtle fibropapillomatosis
Marek’s Dz of chickens causes what type of lymphoma?
Cutaneous follicular lymphoma
Papillomaviruses causes what type of benign masses?
Papilloma
Papillomaviruses causes what types of malignant tumors?
Carcinoma
Sarcoid
How does the papillomavirus cause tumor formation?
inactivation of tumor suppressor genes (p53 & Rb)
Papillomaviruses commonly cause sarcoid in what 2 species?
cats
horses
What other viruses cause cutaneous lesions? (5)
Picorna Rhabdo Calici Parvo Retro
What are the 4 portals of entry for bacterial infections?
Pores
Hematogenous spread
Disruption of the physical barrier
Disruption of immunological barrier
BacT skin infections most commonly affect which species?
Dogs
K9 superficial pyoderma is caused by what?
Staph. pseudintermedius
What are the 4 layers of the skin?
Stratum corneum
Stratum granulosum
Stratum spinosum
Stratum basale
What is the typical transit time of a single keratinocyte?
~ 1 mo.
4 things that make up the basement membrane zone
Hemidesmosomes
Lamina lucida
Lamina densa
Desmosomes
What is the composition and fxn of the dermis?
Composed of collagen, elastin fibers & glycosaminoglycans
Support of other structures
What affects hair growth?
photoperiod, nutrition & health status
Which pathogens can penetrate intact skin?
hookworm larvae
Schistosoma
Which dermatophytes often affect hair & claws?
Microsporum canis
Trichophyton mentagrophytes
Which pathogen often enters via puncture wounds?
Clostridium tetani
Which 2 pathogens often enter through hair follicle openings?
Demodex
Staph.
What is the most important barrier against infection & fluid loss?
Stratum corneum
How do keratintocytes provide structural integrity?
by producing keratin filaments, desomosomes & hemidesmosomes
What comprises the Innate immunity of the skin? (6)
Stratum corneum barrier Macrophages & dentritic cells Phagocytes Endothelial cells Coagulation system Complement cascade
What comprises the Adaptive immunity of the skin? (6)
Langerhans cells CD8 T cells (CTLs) CD4 Th-1 (activate macrophages) CD4 Th-2 (activates B-cells, etc) Endothelial cells Keratinocytes
When does blood clotting occur in the skin?
0-12 hrs post injury
What does inflammation occur?
12-24 hrs. post injury
Recruitment of inflammatory cells.
- Phagocytes –> remove debris
2. Macrophages secrete collagenase –> debridement & tissue remodeling
When does re-epithelialization occur?
3-7 d. post injury
2 things that occur during re-epithelialization
- Keratinocytes produce proteases
2. Re-establishment of basement membrane zone
Fibroplasia occurs when? What mediates it?
3-7 d post injury
Cytokines & growth factors
What do fibroblasts do during fibroplasia?
produce proteolytic enzymes & extracellular matrix proteins
When does angiogenesis occur?
3-7 d post injury
When does wound contraction occur?
after 7 d. post injury
When does tissue remodeling occur?
wks to mos post injury
What are the primary cornification disorders (less common)?
primary seborrhea of cocker spaniel
ichthyosis
What causes secondary cornification disorders (more common)?
chronic stimuli
vit. A deficiency
Disruption of stratum corneum predisposes animals to infections by ____ & _____.
bacT & yeast
What is a common response to chronic stimuli like inflammation or trauma?
Acanthosis
3 causes of dyskeratosis
Zinc-responsive dermatosis
Actinic keratosis
SCC
What 2 immune mediated dzs cause apoptosis of the epidermis?
Lupus erythematosus
Erythema multiforme
3 things that result in atrophy of the epidermis
hormone imbalances
partial ischemia
severe malnutrition
2 common causes of Spongiosis.
Staph.
Malassezia
3 things that cause Hydropic Degeneration
- Lupus erythematosus
- Dermatomyositis
- Drug eruptions
2 things that cause ballooning degeneration
Poxviruses
FMD virus
What viruses commonly cause vesicle formation? (5)
Herpes Pox Morbilli Rhabdo Picorna
Pathogenesis of epidermitis
exocytosis–> spongiosis –> pustules
3 common causes of pustule formation.
- ectoparasite bites
- pemphigoid rxns
- feline eosinophilic dz
2 common causes of exocytosis of lymphocytes.
lupus erythematosus
Malassezia sp. infections
Gross lesion associated w/ K9 superficial pyoderma.
collarettes
Common bacterial causes of impetigo in puppies: (4)
S. aureus, S. intermedius, S. pseudointermedius, & S. schleiferi (all are coagulase + species)
Gross lesions of impetigo.
multifocal pustules & crusts
Histological features of impetigo
NON-FOLLICULAR subcorneal pustules w/ serocellular crusting
K9 mucocutaneous pyoderma is an example of ______ pyoderma.
superficial
Exudative epidermitis of pigs is also known as? Cause?
Greasy Pig Dz
Staph. hyicus
Common name for dermatophilosis? Cause?
Rain Rot/Scald
D. congolensis
Gross lesions of dermatophilosis
papules, pustules & THICK CRUSTS that coalesce w/ matted wool/hair
Cause of Ovine fleece rot? Predisposes sheep to?
Pseudomonas spp.
myiasis (fly strike)
Deep pyoderma occurs most frequently in what species? cause?
dog
Staph pseudointermedius
Folliculitis often leads to _____.
furunculosis
Furunculosis results in:
infection & FB type inflammation
Species that commonly gets furunculosis.
dogs
SQ abscessation is most common in what species?
cats
Necrotizing fasciitis is known as ___. common or rare?
flesh-eating bacT syndrome
rare - in dogs & people
Cause of Necrotizing fasciitis.
Strep. canis
Why can necrotizing fasciitis be life threatening?
due to concurrent septic shock
How do mycobacteria survive inside macrophages?
preventing the fusion of phagosomes & lysomes
2 acid-fast stains used to ID mycobacteria.
Ziehl-Neelsen stain
Fite-Faraco stain
Obligate intracellular parasites cause ___ & _____.
tuberculosis, leprosy
M. tuberculosis & M. bovis _____ cause cutaneous lesions.
rarely
Cause of feline leprosy
M. lepraemurium via bites from cats or rats
Opportunistic pathogens like saprophytic Mycobacterium sp. cause _____.
mycobacteriosis
Non-mycobacterial granulomas are caused by _____ & ______.
non-filamentous bacT granulomas (Botryomycosis), filamentous bacT granulomas
4 examples of idiopathic granulomatous dermatitis (non-infectious)
sterile granuloma
pyogranuloma syndrome
juvenile sterile granulomatous dermatits
lymphadenitis
3 things that can cause lymphadenitits.
juvenile cellulitis
juvenile pyoderma
puppy strangles
Sterile granuloma & pyogranuloma syndrome are common in ____; rare in ___ & ______
dogs
horse & cats
Gross lesions of sterile granuloma & pyogranuloma syndrome.
single or mulitfocal papuples, plaques or nodules on head & extremities
Juvenile sterile granulomatous dermatitis & lymphadenitis occurs in what animals?
puppies < 4 mo.
Lesions of juvenile sterile granulomatous dermatitis & lymphadenitis.
similar to sterile granuloma & pyogranuloma syndrome; includes lymph node involvement; pathogenesis unknown
4 mechanisms affecting blood vessles.
- bacT embolization
- bacT toxins
- direct infection of vascular endothelial cells
- Type III hypersensitivity (immune complex vasculitits)
E. rhusiopathiae creates skin lesions by ____ ____.
bacT embolization
6 bacT w/ cutaneous lesions
R. rickettsia - RM spotted fever Strep. canis Staph. aureus - TSS in dogs E. coli Salmonella E. rhusiopathiae - Diamond skin dz
Septicemic salmonellosis causes _____.
endotoxin-induced venous thrombosis = cyanosis & necrosis of distal extremities
E. coli produces _____. Causes?
Shiga toxin 2e
endothelial damage, vasculitis, resultant edema dz of pigs
Strep. canis & staph. aureus produce ______.
EXOtoxin
R. rickettsia directly infects ____. causes?
endothelial cells
vasculitis & necrotic skin lesions