Lecture 26: Integument 2 Flashcards
Provide 6 examples of portals of entry into the adnexa/epidermis and SC
direct trauma
ganglion migration
absorption
UVA
drug
toxins
List the 6 different inflammatory patterns of the dermis and subcutis
Perivascular/interstitial dermatitis
vascultitis
interface dermatitis
nodular and diffuse
subepidermal vesicular and pustular dermatitis
atrophic dermatosis
What is the most common inflammatory pattern affecting the dermis and subcutis
perivascular/interstitial dermatitis
Define perivascular/interstitial dermatitis
leukocytes move out of vessel and into the perivascular dermis
non specific
What are 3 types of perivascular/interstitial dermatitis
perivascular/interstitial dermatitis
spongiotic perivascular/interstitial dermatitis
hyperplastic perivascular/interstitial dermatitis
What is the common cause of perivascular/interstitial dermatitis? What are the common lesions?
hypersensitivity
urticaria (hives)
What are 5 common causes of spongiotic perivascular/interstitial dermatitis?
immune mediated
hypersensitivity
contact dermatitis
virus
dermatophytosis
- malassezia/yeast
What are 4 common causes of hyperplastic perivascular/interstitial dermatitis
chronic dermatitis
hypersensitivity
lick dermatitis
keratinization
What animals are most commonly affected by perivascular/interstitial dermatitis
horses and cats
List 3 common causes of eosinophilic inflammation
perivascular/interstitial dermatitis
- ectoparasite/allergy/HS
Zn dermatosis
- hyperkeratosis
chronic pyoderma
- staph infection
What are the clinical signs of perivascular/interstitial dermatitis
pruritis
initially no lesions - will develop over time
What is vasculitis? What are 6 common causes
leukocytes targeting vessel walls leading to inflammation, necrosis, and thrombosis
infecting
immune injury
toxin
photodamage
DIC
immune mediated due to type 3 HS (antigen-Ig complex)
List 4 common types of vasculitis
septic
neutrophilic
lymphocytic
eosinophilic
What characterizes septic vasculitis
bacterial antigens in the vessel wall
What are the features of neutrophilic vasculitis
most common vasculitis
leukocytoclastic (neutrophils explode and leave nuclear dust)
non-leukocytoclastic
A pig is presented to you with geometric patterns of macules and ischemic necrosis. What is you top differential? What is a primary cause of the lesions?
septicemia due to erysipelothrix rhusiopathiae
lesions caused by neutrophilic vasculitis leading to inflammation, necrosis, and thrombosis
What are 2 main causes of neutrophilic vasculitis
hypersensitivity
- equine purpura hemorrhagicae
septicemia
What is a common cause of lymphocytic vasculitis and what are the clinical signs
vaccine induced panniculitis
clinically they will have thin, alopecic hair follicles
What are some causes of eosinophilic vasculitis
arthropod/drug/HS/feline eosinophilic granuloma
overall rare
What are 2 types of interface dermatitis and how do they differ? Provide examples of causes of each
cell poor: mild lymphocyte inflam
- dermatomyositis
cell rich: lots of inflammation and apoptosis of basal epithelium
- lupus erythematous
- mucocutaneous pyoderma
What are the common clinical signs of interface dermatitis
pigment incontinance and alopecia
usually affecting the epidermal-dermal border and the basal epithelial keratinocytes
List 4 types of nodular and diffuse inflammation in the dermis and SC. List their respective causes
granulomatous
- trauma/FB implant
neutrophilic/abcess
- bacteria/fungi/algae/protozoa/sterile FB
histiocyte (chronic granuloma)
- sporothrix (fungi)
- staph/strep/peudomonas aeruginosa
- actinobacillus ligneresii
- proteus
-nocaria
-actinomyces
-streptomyces
eosinophil
- habronema
- stephanofilaria
What are the lesions associated with subepidermal vesicular and pustular dermatitis
fragile and transient vesicles
What are the 2 types of subepidermal vesicular and pustular dermatitis
intraepidermal vesicles and pustules
subepidermal vesicles
What is intraepidermal vesicles and pustules characterized by histologically? What causes it?
acantholysis and neutrophils with intracellular edema +/-intercellular edema
bacterial infections
pemphigus autoantibodies
viral
What causes subepidermal vesicles? What are the common clinical signs
defective or autoimmune reactions against adhesion molecules
causing subepidermal edema and urticaria/cellulitis
What is atrophic dermatosis? What are the clinical signs? What causes it?
atrophic follicles with epidermal, sebaceous, and dermal atrophy
+/- hyperkeratosis and follicular keratosis
thin skin and small adnexa
characteristic of endocrine disorders like cushings
What is the main lesions in acute dermatitis
wheal formation due to acute inflammation
dermal edema due to perivascular edema and lymphatic dilation
What is deep pyoderma? What animals is it most common in?
bacterial infection of hair follicles and dermis +/- SC
not super common
- higher risk if low immunity/demodex/follicular hyperkeratosis
mainly in dogs
What is a common causative agent of deep pyoderma
Staphylococcus pseudointermedius
- gram (+)
- folluculitis and furunculosis in dogs
secondary infections from gram (-)
- Pseudomonas
- proteus
- e. coli
List 7 types of inflammation affecting the adnexal structures in the skin
perifolliculitis
mural folliculitis: inflam in wall of follicle
luminal folliculitis: inflam in lumen of follicle
furunculosis: rupture out of follicle
bulbitis: hair bulb
sebaceous adenitis
What is perifolliculitis? What is a common cause?
inflammation around the follicle
demodex in dogs
What is bulbitis
immune mediated inflammation in the hair bulb
usually associated with T cells
What is the primary clinical sign of bulbitis
alopecia
hair bulb atropy causes transition to the telogen (inactive) phase of the hair)
What is sebaceous adenitis? What is the main clinical sign
cell mediated inflammation of the sebacous gland
it is idiopathic
causes alopecia
Describe the steps of folliculitis progression
perifollicular migration
mural folliculitis
luminal folliculitis
furunculosis
inflammation extends deeper forming an abscess or sinus
What is panniculitis and what are 5 causes
inflammation of the SC
infection
immune mediated
physical trauma
nutritional disorder
pancreatic disease
What are the gross lesions of pannicultis? List 4 types of panniculitis
nodules that ulcerate and drain oily/hemorrhagic fluid
neutrophilic
lymphocytic
granulomatous-pyogranulomatous with pathogen
granulomatous-pyogranulomatous without pathogen
What are the common causes of primary and secondary panniculitis respectively
1
- SC adipose
- feline pansteatitis: occur if fed a diet high in polyunsaturated fatty acids and low in antioxidants = lipid peroxidation and pyogranuloma formation
2: contiguous dermal inflammation that connects with the deep SC
What is cellultitis? What are the clinical signs
very deep purulent to pyogranulomatous inflammation +/- hemorrhage, necrosis, thrombosis
+/- bacteria
causing tissue devitalization and sloughing
swelling/erythema/fever/lymphomegaly
What is a severe form of cellulitis? What is it caused by?
necrotizing fasciitis
Streptococcus canis or Staphylococcus pseudointermedius
What are 4 outcomes of dermal/SC inflammation/injury
resolution
abcess
heal with scar
chronic
- delayed HS/granuloma/FB/autoimmune
What is fibrosis/fibroplasia/sclerosis? What is its significance
reduced adnexa and restriction of movement
ex. horse + proud flesh
What are 2 things that can cause solar elastosis
sun exposure neoplasia (SCC)
chronic injury (fibroblast injury)
overall rare
What are 5 types of follicular changes
atrophy
dilation
inflammation
keratosis
dysplasia
What are 4 types of gland changes
inflammation
atrophy
hyperplasia
cysts
What is a normal example of follicular dysplasia?
coat colour dilution
What is an example of collagen dysplasia?
ehlers danlos
reduced tensile strength and increased stretch
histologically normal
higher risk of secondary infection
What is ‘flame figure’ collagen degeneration? What is it usually associated with
dermal deposit of eosinophilic material on collagen
it is common with eosinophilic disorders
- eosinophilic dermatitis
What is eosinophilic dermatitis? What are common causes
cutaneous reactions that can include
feline eosinophilic granuloma complex or plaque/rodent ulcers
canine eosinophilic granuloma
equine nodular collagenolytic granuloma
What animals are primarily affected by eosinophilic dermatitis
cats and horses
Give one example of collagen mineralization
calcinosis cutis due to excess glucocorticoids (iatrogenic or cushings)
What is calcinosis circumscripta? What species is mainly affected
foci of mineralization in areas of trauma that +/- are associated with metastatic calcification of renal failure
mainly dogs
List 3 types of abnormal dermal deposits
calcinosis circumscripta
amyloid
mucin
What causes mucin accumulation in the dermis? What is it?
glucosaminoglycan (GAG) - protein + hyluronic acid which binds water.
myxedema of hypothyroidism
mucinosis
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