Flashcards in Integumentary Pathology Deck (191):
7 steps of regeneration & repair of the skin
Blood clot, inflammation, re-epitheilization, fibroplasia, angiogenesis, wound contraction, remodeling
Hallmark of wound healing
2 responses of the EPIDERMIS to injury
Alteration in growth & differentiation
Alteration in fluid balance & cellular adhesion
3 forms of alterations in epidermal pigmentation
2 dzs that lead to increased production of melanin
2 dzs. that lead to increased melanocytes
What mineral deficiency can result in HYPOpigmentation
Cu deficiency = Acquired lack of melanin production
3 causes of DERMAL atrophy
Iatrogenic (long term steroid use)
What is the early stage of fibroplasia in response to injury?
What is another term for exuberant granulation tissue?
What is the condition that is an inherited abnormality of collagen that results in increased stretchability? Give an example
What are the 3 abnormal deposits in the dermis?
What abnormal deposit in the dermis leads to cutaneous myxedema?
Mucin or hyaluronic acid (GAG)
When can you see cutaneous myxedema? (TQ)
Mucinosis of the Shar-Pei
3 forms of abnormal mineralization/calicification of the dermis
Dystropic mineralization is the result of chronic injury. Give 2 examples.
Which form of mineralization results in deposition of Ca in tissues during hypercalcemia?
(chronic renal dz, hyperparathyroidism, cholecalciferol toxicosis & calcinogenic plants)
What are the characteristics of ACUTE dermatitis?
lasts hrs- several d.
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?
What 4 things can cause ATROPHY of the adnexa?
1. hormonal abnormalities
2. Nutritional abnormalities
4. Stress/poor health
What 4 things can cause HYPERTROPHY of the adnexa?
2. Acral lick dermatitis
3. Chronic allergic dermatitis
4. Chronic bacT/yeast infections
What frequently causes alopecia?
What often leads to abnormalities of hair cycle stages?
Folliculitis is commonly seen with what 2 dzs?
What organisms can cause luminal folliculitis?
Bulbitis is also called _____.
Sebaceous adenitis is most common in what species?
Which form of adenitis is characterized by inflammation of the APOCRINE glands?
Which species are most commonly affected by vasculitis?
Dogs & horses
List some examples of dzs that can cause vasculitis.
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
Vit E deficiency
What are the C.S. of Panniculitis?
painful, palpable nodules --> ulcerated & drain
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
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?
What dzs are associated w/ photo-enhanced dermatoses? (3)
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?
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"?
Acute mosit dermatitis
What physical injury is caused by psychological disorders that lead to persistent licking/chewing?
Acral lick dermatitis
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
Feline Ulcerative Dermatitis Syndrome
1st degree burns affect what layer of skin?
2nd degree burns affect what part of skin.
epidermis & part of dermis
3rd degree burns causes:
full thickness necrosis of skin
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.
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)
What are the C.S. of hyperestrogenism?
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?
What is the immunologic mechanism of urticaria?
Type I & Type III hypersensitivities
What 3 things can cause non-immunologic urticaria?
What species commonly get atopic dermatitis?
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
Which species commonly get miliary dermatitis?
What species of insect causes Sweet Itch in horses?
What is the immunologic mechanism of Allergic Contact Dermatitis?
Gross lesions of allergic contact dermatitis.
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?
What is another name for pemphigus foliaceus?
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?
What is the other name for Pemphigus vulgaris & is more severe?
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?
"Tombstoning" of basal cells
Pathogenesis of bullous pemphigoid (BP)?
AutoAbs directed against hemidesmosomal proteins & subepidermal vesicle formation
Which animals get Bullos Pemphigoid?
Yucatan minipigs (awe!!!)
Gross lesions of Bullos Pemphigoid?
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
Gross lesions of SLE?
lesions start on face & extend to the trunk & extremities
Discoid lupus erythematosus (DLE) only involves which organ?
Gross lesions of DLE are located where?
What is the ANA titer of DLE patients?
NEGATIVE ANA titer
What can DLE lesions be indistinguishable from? How do you DX it ?
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 _____.
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?
Papillomaviruses causes what types of malignant tumors?
How does the papillomavirus cause tumor formation?
inactivation of tumor suppressor genes (p53 & Rb)
Papillomaviruses commonly cause sarcoid in what 2 species?
What other viruses cause cutaneous lesions? (5)
What are the 4 portals of entry for bacterial infections?
Disruption of the physical barrier
Disruption of immunological barrier
BacT skin infections most commonly affect which species?
K9 superficial pyoderma is caused by what?
What are the 4 layers of the skin?
What is the typical transit time of a single keratinocyte?
~ 1 mo.
4 things that make up the basement membrane zone
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?
Which dermatophytes often affect hair & claws?
Which pathogen often enters via puncture wounds?
Which 2 pathogens often enter through hair follicle openings?
What is the most important barrier against infection & fluid loss?
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
What comprises the Adaptive immunity of the skin? (6)
CD8 T cells (CTLs)
CD4 Th-1 (activate macrophages)
CD4 Th-2 (activates B-cells, etc)
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.
1. 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
1. 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
What causes secondary cornification disorders (more common)?
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?
3 causes of dyskeratosis
What 2 immune mediated dzs cause apoptosis of the epidermis?
3 things that result in atrophy of the epidermis
2 common causes of Spongiosis.
3 things that cause Hydropic Degeneration
1. Lupus erythematosus
3. Drug eruptions
2 things that cause ballooning degeneration
What viruses commonly cause vesicle formation? (5)
Pathogenesis of epidermitis
exocytosis--> spongiosis --> pustules
3 common causes of pustule formation.
1. ectoparasite bites
2. pemphigoid rxns
3. feline eosinophilic dz
2 common causes of exocytosis of lymphocytes.
Malassezia sp. infections
Gross lesion associated w/ K9 superficial pyoderma.
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.
Exudative epidermitis of pigs is also known as? Cause?
Greasy Pig Dz
Common name for dermatophilosis? Cause?
Gross lesions of dermatophilosis
papules, pustules & THICK CRUSTS that coalesce w/ matted wool/hair
Cause of Ovine fleece rot? Predisposes sheep to?
myiasis (fly strike)
Deep pyoderma occurs most frequently in what species? cause?
Folliculitis often leads to _____.
Furunculosis results in:
infection & FB type inflammation
Species that commonly gets furunculosis.
SQ abscessation is most common in what species?
Necrotizing fasciitis is known as ___. common or rare?
flesh-eating bacT syndrome
rare - in dogs & people
Cause of Necrotizing fasciitis.
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.
Obligate intracellular parasites cause ___ & _____.
M. tuberculosis & M. bovis _____ cause cutaneous lesions.
Cause of feline leprosy
M. lepraemurium via bites from cats or rats
Opportunistic pathogens like saprophytic Mycobacterium sp. cause _____.
Non-mycobacterial granulomas are caused by _____ & ______.
non-filamentous bacT granulomas (Botryomycosis), filamentous bacT granulomas
4 examples of idiopathic granulomatous dermatitis (non-infectious)
juvenile sterile granulomatous dermatits
3 things that can cause lymphadenitits.
Sterile granuloma & pyogranuloma syndrome are common in ____; rare in ___ & ______
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.
1. bacT embolization
2. bacT toxins
3. direct infection of vascular endothelial cells
4. Type III hypersensitivity (immune complex vasculitits)
E. rhusiopathiae creates skin lesions by ____ ____.
6 bacT w/ cutaneous lesions
R. rickettsia - RM spotted fever
Staph. aureus - TSS in dogs
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 ______.