Jubb and Kennedy Flashcards
1
Q
What are beta-defensins and cathelicidins?
A
Antimicrobial peptides
2
Q
What effect does vitamin D3 have on keratinocytes?
A
It regulates epidermal differentiation and proliferation
3
Q
Match the keratins with the layer of epidermis they are found:
K5 and K14
K2
K1 and K10
Basal layer keratinocytes
Suprabasal keratinocytes
Stratum granulosum
A
K5 and K14 - basal layer keratinocytes
K2 - stratum granulosum
K1 and K10 - suprabasal keratinocytes
4
Q
Desmocollins and desmogleins (cadherin proteins) make up which epidermal structure?
A
Desmosomes
5
Q
Which epidermal structure contains glucosylceramides, sphingomyelin, glycerophospholipids and cholesterol sulfate (plus modifying enzymes)?
A
Lamellar bodies
6
Q
Which enzyme catalyses the formation of the cornified envelope by cross-linking small proteins (e.g. involucrin, loricrin and cystatin A)?
A
Transglutaminase 1
7
Q
In the pig, cat, cow, sheep, goat, horse and human, Birbeck granules are found in which cells?
A
Langerhans cells
8
Q
Which epidermal cells express CD1, MHC II, CD45, vimentin and S-100?
A
Langerhans cells
9
Q
BP230 (BPAg 1) and plectin form which part of the hemidesmosome?
A
Cytoplasmic plaque
10
Q
alpha6 beta4 intergrin and BPAG2 (type XVII collagen) make up which part of the hemidesmosome?
A
Transmembrane portion
11
Q
alpha6 beta4 intergrin binds to laminin 5 - where is laminin 5 located?
A
It is a component of the anchoring filaments of the lamina lucida
12
Q
_____________ are composed of type VII collagen and form looping arrays with one or both ends attached to the lamina densa, thereby anchoring the BMZ to the dermis.
A
Anchoring fibrils
13
Q
Which cytokines can stimulate mast cell proliferation and differentiation?
A
Stem cell factor (SCF) and T cell - derived cytokines: IL-3 IL-4 IL-9 IL-10
14
Q
Which areas of skin are devoid of sebaceous glands?
A
Footpads and nasal planum
15
Q
Ballooning degeneration of the epidermis is the result of intracellular oedema and is characteristic of which disease process?
A
Viral infections, particularly herpesvirus and poxvirus
16
Q
What is the term used for dermal deposition of amorphous eosinophilic material on collagen fibres with an infiltrate of eosinophils?
A
Collagen flame figures
17
Q
Dystrophic mineralisation of the hair follicle basement membrane can be seen as a senile change; which breed is particularly affected?
A
Poodles
18
Q
_________ are dermal papillae devoid of attached epidermal cells that project into a vesicle or bulla.
A
Festoons
19
Q
What are the four types of epidermal hyperplasia?
A
Regular (or psoriasiform)
Irregular
Papillated (digitate projections ABOVE the skin surface)
Pseudocarcinomatous (extreme irregular hyperplasia that may demonstrate increased mitotic activity and branched/fused rete pegs)
20
Q
What are the differentials for eosinophilic perivascular dermatitis?
A
Ectoparasites Food allergy Atopy Zinc-responsive dermatosis Equine multisystemic eosinophilic epitheliotropic disease Chronic pyoderma
21
Q
List a differential for:
Pure perivascular dermatitis
Perivascular dermatitis with spongiosis
A
Pure perivascular dermatitis - acute hypersensitivity reactions and urticaria
Perivascular dermatitis with spongiosis - hypersensitivity reactions, acute contact or irritant dermatitis, ectoparasitism, feline eosinophilic plaque, feline miliary dermatitis, and viral infections.
22
Q
List a differential for:
Perivascular dermatitis with epidermal hyperplasia
Perivascular dermatitis with hyperkeratosis
A
Perivascular dermatitis with epidermal hyperplasia - This is a common, non-diagnostic, chronic reaction pattern e.g. chronic hypersensitivity reactions, acral lick dermatitis, and any dermatitis that has undergone chronic irritation and trauma.
Perivascular dermatitis with hyperkeratosis - The presence of parakeratosis suggests zinc- responsive dermatosis, chronic ectoparasite hypersensitivity, or Malassezia dermatitis.
23
Q
Name two diseases that show a cell-poor interface dermatitis on histopathology
A
Dermatomyositis Ischemic dermatopathy Erythema multiforme Drug eruptions Graft-versus-host reactions Bovine viral diarrhoea Bovine pseudolumpy skin disease
24
Q
Which type of hypersensitivity reaction leads to vasculitis?
A
Type III
25
Name two differential diagnoses for neutrophilic vasculitis
```
Hypersensitivity reactions
Septicemia
Connective tissue disorders
Equine purpura hemorrhagica
Rocky Mountain spotted fever
Classical swine fever
Thrombophlebitis
Idiopathic disorder
```
26
Name two differential diagnoses for lymphocytic vasculitis
Dermatomyositis
Malignant catarrhal fever
Vaccine-induced panniculitis
Rarely in cutaneous lymphoma
27
Name two differential diagnoses for eosinophilic vasculitis
```
Arthropod insult
Drug eruptions
Food hypersensitivity
Equine axillary nodular necrosis
Idiopathic nodular eosinophilic vasculitis in horses
Feline eosinophilic granulomas
Rarely in mast cell tumours
```
28
Tuberculoid granulomas can be seen in tuberculosis, feline leprosy, atypical mycobacterial infection and which other infection?
Corynebacterium pseudotuberculosis
29
Which MNGC have nuclei that form a circle or semicircle at the periphery of the cell?
Langhans cell
30
Which MNGC have nuclei that form a wreath that surrounds a central, homogeneous, amphophilic core of cytoplasm that is, in turn, surrounded by abundant foamy cytoplasm
Touton cell
31
Which MNGC have nuclei that are scattered throughout the cytoplasm
Foreign body
32
What are Russell bodies?
Eosinophilic intracytoplasmic inclusions in plasma cells; accumulations of glycoprotein are largely globulin and may be large enough to displace the cell nucleus.
33
```
Name a disease where you see:
Subcorneal pustules/vesicles
Pustules/vesicles in stratum spinosum
Suprabasilar pustules/vesicles
Intrabasilar vesicles
```
Subcorneal pustules/vesicles - PF, superficial pyoderma, hypersensitivities (eos)
Pustules/vesicles in stratum spinosum - pemphigus complex, viral disease, rarely in SND/NME
Suprabasilar pustules/vesicles - pemphigus vulgaris
Intrabasilar vesicles - lupus, dermatomyositis, EM, GvH disease TEN
34
In which species is follicular inflammation most common?
Dogs
35
Idiopathic sterile eosinophilic folliculitides may be seen in which species?
Dogs and cattle
36
Name two causes of sterile eosinophilic folliculitis in cats and horses
```
Hypersensitivity reactions (mosquito-bite hypersensitivity, atopy, food allergy, onchocerciasis, equine eosinophilic granuloma, Culicoides hypersensitivity, flea-bite hypersensitivity).
Feline herpesviral dermatitis.
```
37
What type of folliculitis is seen in pseudopelade?
Mural folliculitis
38
Panniculitis can be associated with which vitamin deficiency?
Vitamin E deficiency
39
Which veterinary species has harlequin ichthyosis been reported in?
Cows
| Kudu (antelope)
40
In epidermolytic ichthyosis, what are the histopathological findings?
Vacuoles and lysis of keratinocytes within the spinous and granular cell layers, which occur along with hypergranulosis and hyperkeratosis.
41
Epidermolytic ichthyosis (a defect in keratin formation) is seen in which breed of dog and genetic mutation?
Norfolk terrier
| KRT10 mutation
42
Which gene mutation is associated with nonepidermolytic ichthyosis in JRTs?
Transglutaminase 1 (TGM1)
43
Match the following breeds with the gene mutation associated with nonepidermolytic ichthyosis:
Golden retrievers
American Bulldogs
PNPLA1
ICHTHYN/NIPAL4
Golden retrievers - PNPLA1
| American Bulldogs - NIPAL4/ICHTHYN
44
CKCS nonepidermolytic ichthyosis is associated with which clinical signs?
```
Keratoconjunctivitis noted from the beginning of eyelid opening
A roughened/curly haircoat
Scaling with abdominal hyperpigmentation
Footpad hyperkeratosis
Nail dystrophy
```
45
Hereditary zinc deficiency has been reported in which veterinary species?
Cattle
| Bull terrier dogs
46
At what age are skin lesions apparent in lethal acrodermatitis in Bull terriers?
6-8 weeks
47
Which organ is small or absent in hereditary zinc deficiency in cattle and Bull terriers?
Thymus
48
Which type of EB is this?
Cytolysis of basal keratinocytes produces intraepidermal clefting. This form of the disease is caused by fragility of the epidermal basal cells because of mutations in basal cell–specific keratins 5 and 14.
Epidermolysis bullosa simplex
49
Which type of EB is this?
Clefting occurs within the lamina lucida because of abnormalities of the anchoring filament-hemidesmosome complexes, which may be reduced in number and poorly formed or may be completely absent.
Junctional epidermolysis bullosa
Most cases of JEB are the result of a deficiency or abnormality in one of the hemidesmosome-associated proteins laminin-5, collagen XVII (also called BPAG 2 and BP180), or integrin α6β4, or the extracellular protein LAD-1.
50
Which type of EB is this?
Characterized by a split in the superficial dermis below the lamina densa in the region of the anchoring fibrils, which are fewer in number and distorted or completely absent. The molecular cause is a mutation in the anchoring fibril protein, type VII collagen.
Dystrophic epidermolysis bullosa
51
Which special stain can help locate the basement membrane zone in histopathology of EB?
PAS
52
EBS has been associated with which gene mutation in cattle?
KRT5
53
JEB in German black-headed mutton sheep has been associated with which mutation?
LAMC2 (reduced laminin-5)
54
Which gene mutation has been associated with JEB in Breton and Comtois horses?
And American Saddlebreds?
Breton and Comtois - LAMC2
| American Saddlebreds - LAMA3
55
Which gene mutation is associated with JEB in GSHP?
The disease is associated with reduced expression of laminin 5 and is caused by a mutation in the LAMA3 gene for the laminin α3 chain.
56
What are 'corps rounds'?
Dyskeratotic keratinocytes with small pyknotic nuclei, a perinuclear clear halo, and eosinophilic cytoplasm
57
Autosomal recessive acantholytic dermatosis in Chesapeake Bay retrievers is associated with a mutation of which gene?
PKP1
Associated with loss of plakophilin-1 in desmosomal attachments as well as abnormal arrangement of desmoplakin and keratins 10 and 14
58
Which breed of cattle are affected by lethal hypotrichosis?
Holstein-Friesian
| Japanese native
59
What are the clinical signs of congenital hypotrichosis of Hereford cattle?
Alopecia is variable and non-progressive. Calves have thin, pliable skin, extremely curly facial hair, and may have sparse pelage of thin soft curly, easily broken and epilated hairs, or be completely hairless. Some calves also have impaired hoof development.
60
What are the histopathological findings in congenital hypotrichosis of Hereford cattle?
The condition is characterised histologically by hypoplastic or degenerate hair follicles with vacuolation and necrosis of Huxley’s and Henle’s layers and abnormally large trichohyaline granules in Huxley’s layer. Most follicles contain fragmented hair shafts. Arrector pili muscles are reduced in number and frequently not associated with hair shafts.
61
A mutation in which gene is linked to X-linked hypohidrotic ectodermal dysplasia (XHED)?
Affected dogs have a triad of lesions: patterned hairlessness, an absence of atrichial sweat glands, and dental abnormalities (conically shaped teeth, anodontia).
Ectodysplasin 1 (ED 1)
62
A semi-dominant form of ectodermal dysplasia in congenitally hairless breeds of dog has been associated with which gene?
Forkhead box transcription factor family (FOXI 3)
63
What are the typical age of onset of clinical signs in colour dilution alopecia vs. black hair follicular dysplasia?
Colour dilution alopecia - few months to a few years of age
Black hair follicular dysplasia - few weeks to few months of age
64
Hairy shaker disease in lambs leads to what hair coat changes seen at birth?
To affect the hair coat, at what part of gestation does infection need to occur?
They have a long, straight, coarse coat.
This develops when infection occurs prior to day 80 of gestation.
65
Name a breed of dog affected by dermatomyositis other than Collies and Shetland sheepdogs
Beauceron Shepherd, Belgian Tervuren, and Portuguese Water dogs
66
What are the five subtypes of ischaemic dermatopathy?
1. Canine familial dermatomyositis
2. Juvenile-onset ischemic dermatopathy (similar to canine familial dermatomyositis except for the breed predispositions)
3. Focal postrabies vaccination reaction
4. Generalized vaccine-induced ischemic dermatopathy
5. Adult-onset non–vaccine-induced generalised ischemic dermatopathy.
67
What are the early clinical lesions of dermatomyositis?
Small pustules, vesicles, papules, and nodules that evolve into erythematous, crusty, ulcerated, alopecic areas with hypopigmentation or hyperpigmentation.
68
What is the most consistently present histological abnormality in dermatomyositis?
The most consistently present histologic abnormalities are follicular atrophy and perifollicular inflammation that may be accompanied by perifollicular fibrosis.
69
In inherited collagen dysplasia, healing of wounds usually proceeds normally but results in what type of scar?
Characteristic thin, pale wrinkled scars resembling tissue paper.
70
```
Rank the species in order of severity of clinical signs of inherited collagen dysplasia:
Dogs
Horses
Cats
Sheep
Cattle
```
Sheep > cattle > dogs > cats > horses
71
Collagen dysplasia (AKA dermatosparaxis) in cattle is due to a mutation in the gene for which enzyme?
Procollagen I N-proteinase (AKA procollagen aminopeptidase).
The enzyme that excises the amino-propeptide of type I and type II procollagens.
This leads to assembly of abnormal ribbon-shaped collagen fibrils lacking normal tensile strength.
72
Hereditary equine regional dermal asthenia (HERDA) affects which breed of horse?
Quarter Horse
73
Hereditary equine regional dermal asthenia (HERDA)
What are the clinical signs?
The affected horses have hyperextensible and loose fragile skin that results in poor wound healing and disfiguring scars.
74
At what age is hereditary equine regional dermal asthenia (HERDA) usually recognised?
6-12 months
75
What are the histopathological findings in cats with skin fragility syndrome?
Profound atrophy of dermal collagen fibres.
Collagen fibres are thin and disorganised. Hair follicles are in kenogen and markedly atrophied. The epidermis and other adnexa are also often atrophic. There may be orthokeratotic hyperkeratosis.
76
Which conditions have been associated with feline skin fragility?
```
Spontaneous and iatrogenic hyperglucocorticism
Diabetes mellitus
Cholangiohepatitis
Hepatic lipidosis
Cholangiocarcinoma
Multicentric follicular lymphoma
Feline infectious peritonitis
Disseminated histoplasmosis
Administration of various drugs, including megestrol acetate and other progestational compounds
```
77
What is proteoglycan a major component of?
The extracellular ground substance of the dermis
78
In cutaneous mucinosis of Shar-Peis, which cells excessively produce hyaluronic acid?
Dermal fibroblasts
79
Cutaneous mucinosis of Shar-Peis is associated with higher expression of which enzyme?
Hyaluronan synthase 2 (HAS2)
80
Which special stains can be used to better visualise mucin?
```
Alcian blue (stains mucin blue-green)
Mucicarmine (stains mucin red)
```
81
Dermatosis vegetans is an inherited disorder affecting which species?
Pigs - autosomal recessive in Landrace
82
How do dermoid cysts form?
They are caused by defective epidermal closure along embryonic fissures, which isolates an island of ectoderm in the dermis or subcutis.
83
Dermoid cysts have been reported in dogs and which other veterinary species?
Horses (TBs)
Cattle (Angus)
Cats (DSH)
84
Keratinocytes are anchored to the basement membrane by hemidesmosomes and which other structure?
Focal adhesions
85
Which keratins are expressed in the basal keratinocytes and the suprabasal keratinocytes?
Basal - K5 and K14
| Suprabasal - K1 and K10
86
What do focal adhesions and adherens junctions connect to?
Actin filaments - they are transitory adhesions
87
Which proteins mediate cell-substrate and cell-cell adhesion?
Integrins are receptors that mediate cell-substrate adhesion, whereas cadherins mediate cell-cell adhesion.
88
The keratin intermediate filaments in keratinocytes aggregate into what structure that connects with desmosomes, and therefore indirectly with adjacent cells?
Tonofilaments
89
Which keratins are acidic and which are basic?
K1-8 are basic (type II)
| K9-20 are acidic (type I)
90
Which enzymes are thought to be responsible for desmosomal degradation and subsequent keratinocyte desquamation?
Hydrolytic enzymes, such as cathepsin B–like, carboxypeptidase, and acid phosphatase
91
Name three nutritional factors that can influence proper differentiation and maintenance of the epidermis?
```
Amino acids
Vitamins A or B
Zinc
Fatty acids
Copper
```
92
What are the histopathological findings in feline acne?
Histologically, the lesions consist of dilated sebaceous gland ducts, follicular keratosis with plugging and dilation, chronic periadnexal lymphoplasmacytic inflammation, and less commonly, luminal folliculitis and furunculosis.
93
Congenital digit hyperkeratosis occurs is which breeds of dog?
Irish terrier
| Dogue de Bordeaux
94
Labradors with nasal parakeratosis develop verrucous brown scale and what other clinical sign on the nasal planum?
Variable depigmentation
95
What are the characteristic histological features of Labrador Retriever nasal parakeratosis?
Marked parakeratotic hyperkeratosis with serum lake formation with a band of lymphocytes and plasma cells in the superficial dermis. Other histopathologic findings include epidermal hyperplasia, neutrophilic and lymphocytic exocytosis, and pigmentary incontinence.
96
Which breed is most commonly affected by equine linear keratosis?
Quarter horse
97
Which body sites are most commonly affected by equine linear keratosis?
Neck, shoulder, and lateral thorax
98
What are the histopathological findings in equine linear keratosis?
Lymphocytic or lymphohistiocytic mural folliculitis, sometimes with follicular destruction. Multinucleated giant cells and eosinophils are variably present. Sebaceous glands can be secondarily effaced, and there is a variable amount of orthokeratotic or parakeratotic hyperkeratosis, with or without superficial perivascular non- suppurative inflammation.
99
Linear keratoses with a similar gross and histologic appearance to equine linear keratosis have also been described in which species?
Cattle
100
In equine cannon keratosis, which part of the cannon is affected?
The lesions consist of vertically oriented, moderately well-demarcated areas of alopecia, scaling, and crusting on the cranial surface of the rear cannon bones. Lesions are usually, not painful nor pruritic, are bilateral and persist for life.
101
Cutaneous horn can be associated with which infectious diseases?
In cattle, sheep, and goats, cutaneous horns may arise in lesions of dermatophilosis.
In the cat, multiple cutaneous horns on the footpads have been reported in association with feline leukemia virus (FeLV) infection.
102
Which breeds of dog are predisposed to sebaceous adenitis?
```
Akita
Standard Poodle
Samoyed
Vizsla
Lhasa Apso
Havanese
```
103
What are the early clinical signs of sebaceous adenitis in short-coated dogs?
Patches of scaling and alopecia tend to appear on the ears and dorsum. These progress to annular areas of alopecia and scaling on the trunk and head.
104
Sebaceous gland destruction in sebaceous adenitis may progress more quickly in short- or long-coated dogs?
Long-coated dogs tend to have rapid and complete sebaceous gland destruction with little residual inflammation.
105
What are the three proposed mechanisms of pathogenesis in sebaceous adenitis?
(1) destruction of the gland resulting from immune-mediated mechanisms, leading to secondary hyperkeratosis
(2) a primary keratinization defect, resulting in increased amounts of follicular keratin blocking the sebaceous duct and causing inflammation of the gland
(3) a defect in the structure of the sebaceous duct or gland, resulting in inflammation directed at free sebum.
106
Vitamin A responsive dermatosis has been reported in Cocker spaniels and which other breeds?
Labrador
| Miniature Schnauzer
107
What are the clinical signs of vitamin A responsive dermatosis?
Clinical lesions consist of hyperkeratotic plaques with follicular plugging and follicular casts on the ventral and lateral chest and abdomen. The dogs may have a greasy haircoat with ceruminous otitis.
108
What are the histopathological features of vitamin A responsive dermatosis?
The histologic features are marked follicular orthokeratotic hyperkeratosis, which is more severe than the epidermal surface hyperkeratosis.
109
In lichenoid-psoriasiform dermatosis of springer spaniels, which inflammatory cell predominates?
Histopathologic findings include lichenoid band of predominantly of plasma cells
110
Is basal cell apoptosis a feature of lichenoid-psoriasiform dermatosis?
No - they are present in low numbers
111
What are the histopathological features of ear margin dermatosis?
Histopathologic findings are characterized by marked orthokeratotic and/or parakeratotic hyperkeratosis with follicular keratosis and variable mild superficial perivascular dermatitis.
112
Do type 1 and 2 melanosomes contain melanin?
No
113
What shape are the melaonsomes producing eumelanin?
Round melanosomes produce eumelanins and elliptical melanosomes produces pheomelanins
114
Melanin pigments arise from the common metabolic pathway of conversion of tyrosine to 3, 4-dihydrophenylalanine (DOPA) and then oxidation to what?
DOPAquinone
115
Tyrosinase contains which mineral element and what does it do?
Copper
Catalyses tyrosine to DOPA
116
Melanotrichia can occur following insect bites in horses and which insult in white Merino sheep?
UV light exposure
117
In canine acanthosis nigricans, which layers of the epidermis are heavily melanised?
All layers of the epidermis are heavily melanised
118
What is the phenotype associated with Waardenburg syndrome?
White coats, blue or heterochromic irides and deafness
119
A type of Waardenburg syndrome in American Paint horses is fatal in foals due to what?
Aganglionic colon - foals develop colic and die shortly after birth
120
Piebaldism is associated with a mutation in the gene encoding for what?
C-kit tyrosine kinase or stem cell factor (the receptor ligand)
The c-kit tyrosine kinase receptor is associated with proliferation and survival of melanoblasts.
121
Vitiligo has been described in which dog breeds?
Belgian Tervuren, Doberman Pinscher, Newfoundland, Rottweiler, German Shepherd, Dachshund, German Shorthaired Pointer, and Old English Sheepdogs.
122
Which breeds are affected by "Dudley" or "snow" nose?
This is commonly seen in the Golden Retriever, Nordic breeds (Siberian Husky, Malamute), and yellow Labrador Retrievers.
123
Vitiligo has been reported in which breed of cat?
Siamese
124
Are melanocytes present in albinism?
Melanocytes are present and normally distributed but are defective in function and fail to synthesise melanin.
125
Cyclic haematopoiesis is associated with a mutation in which gene?
AP3
126
Hypopigmentation in horses can be associated with which diseases?
```
Onchocerciasis
Culicoides hypersensitivity
Ventral midline dermatitis
Coital vesicular exanthema
Rubber contact
```
127
Depigmentation in dogs has been reported with which infectious diseaes?
Leishmaniosis
| M. persicolor dermatophytosis
128
What histopathological pattern is seen in uveodermatological syndrome?
Lichenoid interface with histiocytes and fewer neutrophils, lymphocytes and plasma cells. Basal cell apoptosis and vacuolar change are uncommon.
129
What are the four stages of decubitus ulcers?
In grade I, the lesion consists of focal erythema.
In grade II, an ulcer extends into the subcutis.
In grade III, the ulcer extends into the deep fascia, and the wound edges may be undermined.
Grade IV ulcers extend to bone, have under- mined edges, and possibly underlying osteomyelitis and septic arthritis
130
What disease consists of subcutaneous nodules composed of sheets of large macrophages in which the cytoplasm is filled with homogeneous eosinophilic spherules. These structures may resemble fungal organisms but are negative with fungal special stains such as periodic acid–Schiff. The spherules stain for endogenous peroxidase, thus establishing their identity as erythrocytes
Myospherulosis
131
What is the classical histopathological finding in injection site reactions?
Histologically, the classic injection site reaction is composed predominantly of nodular aggregates of lymphocytes arranged around a central core of caseous necrosis.
132
What are differential diagnoses for exuberant granulation tissue in the horse?
```
Sarcoid
Habronemiasis
Mycoses
Pythiosis
SCC
```
133
Which body sites are most commonly affected by cold injury?
Ears and tail of cats
Scrotum of male dogs and bulls
Tips of the ears, tail, and teats in cattle
134
Which type of thermal exposure is the most damaging?
Longer exposure to lower temperatures is more damaging than short exposure to higher temperatures
135
Define first degree burns
First-degree burns involve only the epidermis.
The heated areas are erythematous and edematous as a result of vascular reaction in the dermis, but vesicles do not form. The epithelial cells show no morphologic sign of injury, although there may be surface desquamation after a few days.
136
Define second degree burns
In second-degree burns, the epidermis and part of the dermis are damaged.
The cytoplasm of the epithelial cells is hypereosinophilic, and the nuclei are shrunken or karyorrhectic. Coagulative necrosis of the epidermis (Fig. 6-45) can occur in the absence of substantial dermal injury and often “wicks” down to involve the follicular epithelium. Vesicles and bullae form in the epidermis, often at the dermoepidermal junction.
137
Define third degree burns
In third-degree burns, the destructive effect of the heat extends full thickness through the epidermis and dermis, causing coagulative necrosis of connective tissues, vessels, and adnexa. Thermal injury causes thrombosis of blood vessels and vascular leakage, leading to the coagulative necrosis of more superficial tissues.
138
Define fourth degree burns
Fourth-degree burns are similar in character to those of third degree but penetrate below the dermis to and beyond the sub- cutaneous fascia. Heat in surface tissue is conducted to deeper tissues via the blood and lymph. The degree of injury may not be evident for several days after the insult occurred. Follicular and sweat gland damage continues for 24-48 hours.
139
In which type of thermal injury can you find eosinophilic, wavy elastin fibrils in the superficial dermis (“red spaghetti of Walder”)?
Radiant heat dermatitis (erythema ab igne)
140
Which affect of acute radiation injury is not reversible?
Damage to sebaceous glands is not reversible and leads to permanent scaling
141
Where do skin lesions start in dogs and cats with thallium toxicosis?
The pattern of skin involvement in cats and dogs is characteristic, beginning at the commissures of the lips or nasal cleft, occasionally on the ear margins, and expanding over the face and head.
142
What is characteristic about the mucous membranes in thallium toxicosis?
The mucous membranes are characteristically “brick-red” and may be ulcerated
143
What change to the surface and follicular epithelium is seen with thallium toxicosis?
Thallium severely alters the cornification process, and both the surface and external root sheath epithelium demonstrate marked parakeratotic hyperkeratosis
144
The presence of arsenic in the skin increases its susceptibility to what?
UV light damage
145
How does ischaemia occur in gangrenous ergotism?
Gangrenous ergotism is due to direct stimulation of adrenergic nerves supplying arteriolar smooth muscle. This produces marked peripheral vasoconstriction. Arteriolar spasm and damage to capillary endothelium leads to thrombosis and ischemic necrosis of tissues.
146
Macrocyclic trichothecene toxins produced by the fungus Stachybotrys spp. cause stachybotryotoxicosis, what are the skin lesions?
Ulcerative and necrotizing lesions of the skin and mucous membranes have been reported in horses, cattle, sheep, and pigs
147
What are the skin lesions seen in cattle with hairy vetch toxicosis?
Initial lesions consist of a rough coat with papules and crusts affecting the skin of the udder, teats, escutcheon, and neck, followed by involvement of the trunk, face, and limbs. The skin becomes less pliable, alopecic, and lichenified. Marked pruritus leads to excoriations.
148
What is photoallergy?
Photoallergy occurs when the photoproduct of an exogenous chemical acts as an antigen.
149
What is the difference between actinic and solar?
“actinic” is defined as ultraviolet (UV) rays from sunlight and UV lamps, whereas “solar” refers to radiation from the sun
150
Which solar radiation rays are:
100-400 nm
400-700 nm
700 nm - 1mm
```
UV light (100-400 nm)
Visible light (400-700 nm)
Infra- red light (700 nm to 1 mm)
```
151
What are the wave lenghts of UVA and UVB and which most often causes skin damage?
UVA 320-400 nm
UVB 290-320 nm
Most of the direct photobiologic reactions in the skin are induced by high-energy light in the ultraviolet radiation UVB range
152
Name three chromophores in the skin
Chromophores include keratin proteins, melanin, carotene, nucleic acids, peptide bonds, and some amino acids
153
Light absorbed by chromophores results in electron transfers and production of what?
Free radicals
154
UV light induces mutations of which gene in keratinocytes?
p53 tumour suppressor
Contributing to a proliferative advantage to mutated cells that is found in solar-induced actinic keratoses and squamous cell carcinomas in humans.
155
UVB radiation reduces the number of which non-keratinocyte epidermal cell?
Langerhans cells
Also impairs their antigen presenting function
156
What are the characteristic histopathological features of acute sun-induced epithelial damage?
Apoptotic keratinocytes, “sunburn cells,” arranged singly or in clusters or bands in the outer stratum spinosum
157
In severe sun-induced burns, lesions include spongiosis, vacuolation of keratinocytes, loss of the granular layer and...
Vesiculation, marked vascular damage, erythrocyte extravasation, and neutrophilic exocytosis
158
UV irradiation causes transient erythema - how?
Probably from a direct heating effect and the photobiologic effects of UVB acting directly on dermal capillaries
159
UV irradiation causes delayed erythema - how?
The delayed erythema reaction may be due to direct damage to endothelial cells or the release of cytokines from the radiation-damaged keratinocytes
160
What adaptive epidermal responses are seen with UV radiation?
Epidermal hyperplasia
| Altered melanin pigmentation
161
How does melanin help protect the skin from UV radiation?
Melanin both absorbs and scatters UV radiation and, being able to trap free radicals, is important in minimising the deleterious effects of incident photons
162
In solar dermatitis in dogs, early lesions of scaling and erythema evolve into what?
Thick, lichenified, erythematous, crusted patches and plaques and haemorrhagic bullae.
163
What is the most consistent histologic finding in dogs with chronic solar dermatitis?
A narrow, hypocellular, pale-staining band of collagen along the dermoepidermal junction. This change may be present prior to clinical signs of actinic dermatitis and may be used as an indicator of solar damage.
164
Can actinic comedones be seen in dogs with chronic solar dermatitis in the absence of other skin lesions?
Yes
165
Increased expression of which enzyme appears to play an early role in actinic keratosis and SCC?
Cyclooxygenase-2 (COX-2)
166
What does COX-2 over-expression lead to?
Increased expression of prostaglandin E2 (PGE2). Activation of the COX-2/PGE2 pathway induces cell proliferation, inhibits apoptosis, and promotes angiogenesis and carcinogenesis.
167
COX-2 expression in SCC has been shown in rats, people and which other species?
Cats, dogs and horses
168
Solar elastosis appears in H&E- stained sections as scattered or agglomerated, thick, irregular, basophilic degenerate elastic fibres, which special stains can be used to demonstrate these changes?
Silver stains
169
What are the histological features of chronic solar keratosis?
Pronounced epidermal hyperplasia with dysplasia, orthokeratotic and parakeratotic hyperkeratosis, perivascular mononuclear cell infiltrates, and dermal scarring, but seldom develop significant solar elastosis, as typifies human solar keratoses. Can also develop cutaneous horn.
170
In photosensitisation, the energy from the absorbed light leads to tissue injury by reacting directly with molecular oxygen, producing what?
Reactive oxygen intermediates, such as superoxide anion, singlet oxygen, and hydroxyl radical
171
In photosensitisation, oxygen free radicals are formed by absorbed light energy and what other route?
Oxygen free radicals may also be formed indirectly, as the result of calcium-dependent, protease-mediated activation of xanthine-oxidase in the skin
172
In photosensitisation, release of reactive oxygen species initiates chain reactions that lead to what?
Mast cell degranulation and damage to cell membranes, nucleic acids, proteins and subcellular organelles, particularly lysosomes and mitochondria
173
What is primary photosensitisation?
Ingestion of plants or drugs containing photoreactive substances
174
What is type II photosensitisation?
Inability to properly metabolise heme pigments leads to build up of haematoporphyrins
175
What is type III photosensitisation?
Abnormal build up of phylloerythrin (degradation of chlorophyll) due to liver disease
Most common form in domestic animals
176
What is type IV photosensitisation?
Idiopathic
177
What are the initial lesions of photosensitisation?
Erythema and oedema (odema can be prominent in sheep - muzzle swelling can cause dyspnoea -'big head')
178
What are the histopath features of photosensitisation?
- Coagulative necrosis of the epidermis and possibly the follicular epithelium, adnexal glands, and superficial dermis.
- Subepidermal clefts or vesicles and dermal odema.
- Endothelial cells of the superficial, mid, and occasionally deep dermal vessels are often swollen or necrotic.
- Fibrinoid degeneration of vessel walls and thrombosis may be present. - Initially, inflammation is sparse, but soon the lesions are infiltrated by neutrophils.
179
The majority of photosensitising plants contain pigments belonging to which families?
The helianthrone or furocoumarin family of pigments
180
Which plants contain helianthrone pigments?
St John's wort
| Buckwheat
181
Which plants contain furocoumarin pigments?
Spring parsley
Bishop's weed
Dutchman's breeches
182
How do furocoumarin pigments differ from helianthrone pigments?
The furocoumarin pigments also induce corneal oedema and keratoconjunctivitis
183
Bovine congenital hematopoietic porphyria is the result of a deficiency in which enzyme?
Uroporphyrinogen III cosynthetase, a key enzyme in heme biosynthesis.
184
Red discolouration of which tissues occurs in bovine congenital hematopoietic porphyria?
Teeth (dentin) and bone (fluoresce in UV light)
| Pigment is deposited in other tissues but is also visible in lungs, spleen and kidney
185
How is urine affected in bovine congenital hematopoietic porphyria?
It is amber to brown, darkens on exposure to light, and fluoresces bright red on exposure to UV radiation
186
What are the histopath lesions of bovine congenital hematopoietic porphyria?
Subepidermal clefts, hyalinization of dermal capillary walls, and a minimal infiltrate of inflammatory cells. The basement membrane zone lines the base of the subepidermal cleft, in some instances covering small projections of dermal papillae (festoons).
187
Which breed of cat has reported been affected by type II photosensitisation?
Siamese
The defect is presumably a deficiency of uroporphyrinogen cosynthetase III, as has been established in humans and cattle.
188
Phylloerythrin, a breakdown product of chlorophyll, is assimilated by hepatocytes and excreted by what route?
Bile
189
Hepatotoxic photosensitisation is most often caused by what?
Toxic plants and mycotoxins
190
What are the histopath findings of photoactivated vasculitis in the horse?
Dermal oedema, vascular dilation and intramural inflammatory cells, leukocytoclasia with nuclear dust, microhemorrhages, and thickening of the vessel wall of the small superficial, mid, and deep dermal vessels. Thrombi may be seen. The epidermis may be eroded or ulcerated but undergoes papillary hyperplasia over time.
191
Keratin production requires high levels of ____-containing animo acids.
Sulphur
192
Hair growth and keratinisation can require what % of an animal's daily protein requirement?
20-30%
193
What are the clinical signs of fatty acid deficiency?
Diffuse scaling, loss of hair coat sheen, and alopecia. Initially dry scaling but over months progresses to an oily, often pruritic stage.
194
What is an essential fatty acid for cats?
Arachidonic acid
They lack delta-6-desaturase, the enzyme responsible for converting linoleic and linolenic acids to longer-chain fatty acids
195
Follicular hyperkeratosis and/or plugging is seen with vitamin A deficiency in which species?
Pigs, cats and dogs
Cattle show scaling and crusting
196
What are the predilection sites for skin lesions with vitamin A responsive dermatosis in dogs?
Ventral and lateral chest and abdomen
197
What is the prednominant histopath finding in vitamin A responsive dermatosis?
Marked follicular orthokeratotic keratosis
198
Which clinical signs are seen with B vitamin deficiencies?
Dry, flaky scale with alopecia, anorexia, and weight loss
199
What are the clinical signs of biotin deficiency in dogs?
Dry, brittle, haircoat, scaling, and leukotrichia. Periocular and facial alopecia can resemble the clinical lesions of systemic lupus erythematosus, discoid lupus, or other dermatoses affecting the face
200
Vitamin C (ascorbic acid) is required for the proper synthesis and structural maintenance of which dermal element?
Collagen
201
Vitamin E responsive dermatosis has been described in goats fed a diet deficient in which mineral?
Selenium
- Periorbital alopecia and generalized seborrhea with a dull and brittle coat
202
Causes of dietary zinc deficiency include diets high in what?
Phytates
Calcium
Iron
other zinc chelating agents
203
What are important differentials to consider clinically for zinc responsive dermatosis in pigs?
```
Sarcoptic mange (usually pruritic cf zinc responsive)
Exudative epidermitis (usually occurs in younger pigs and is greasy)
```
204
What signalments are associated with zinc responsive dermatosis in alpacas?
Dark fleeces
| Breeding females
205
Zinc responsive dermatosis syndrome 1 is seen with which signalments?
Siberian Huskies and Alaskan Malamutes (rarely other breeds)
Usually by one year of age
Older dogs may develop lesions during times of stress
206
Can the lesions of zinc responsive dermatitis be unilateral initially?
Yes, often progress to bilateral
207
Dogs with zinc- responsive dermatosis have decreased epidermal immunoreactivity for metallothioneins, what is their role?
Sulfhydryl-rich proteins that store zinc and act as free radical scavengers
208
Zinc responsive syndrome 2 is seen in puppies and is probably secondary to what?
Excessively high levels of calcium and/or phytates in the diet in rapidly growing animals - excessive iron in drinking water may also contribute.
209
What are the histopathological features of zinc responsive dermatosis?
Papillary epidermal hyperplasia, marked spongiotic parakeratotic hyperkeratosis affecting the epidermis and follicular ostia, and multifocal neutrophilic crusts. Mild to moderate superficial perivascular mononuclear or eosinophil-rich dermatitis is present
210
What are the histopathological differentials for zinc responsive dermatosis?
Superficial necrolytic dermatitis, lethal acrodermatitis, thallium toxicity, and chronic hypersensitivity dermatitis
211
Are serum and plasma zinc levels an accurate method of assessing zinc status in dogs with zinc responsive dermatosis?
No - even in a normal animal values vary widely according to sex, age, stress, concurrent disease, and collection methods
212
What is the 'white' in the 'red, white and blue' of SND?
A band of hydropic, pale-staining keratinocytes in the upper half of a usually acanthotic stratum spinosum. Both intracellular and intercellular oedema contribute to the epidermal pallor.
213
Which feature associated with individual necrotic keratinocytes can help differentiate SND from EM?
In SND, the necrotic keratinocytes lack satellitosis.
214
What is the 'blue' in the 'red, white and blue' of SND?
Basal keratinocyte layer hyperplasia
215
Has SND, or a similar syndrome, been reported in veterinary species other than dogs?
Cats (does affect pads! Asakawa et al, 2013).
| Horses
216
What are the common histopathological features of an endocrinopathy?
- Orthokeratotic hyperkeratosis
- Follicular dilation and keratosis
- Hair follicle atrophy
- Absence of hair shafts in follicles
- Increased numbers of telogen follicles
- Variably increased trichilemmal cornification (flame follicles)
- Epidermal hyperpigmentation.
217
Which breeds are predisposed to hypothyroidism?
Doberman Pinscher, Golden Retriever, Chow Chow, Great Dane, Irish Wolfhound, Boxer, English Bulldog, Dachshund, Afghan Hound, Newfoundland, Alaskan Malamute, Brittany Spaniel, Poodle, Irish Setter, and Miniature Schnauzer
218
In which farm species has a hereditary form of hypothyroidism been reported?
Merino sheep, goats and Afrikander cattle - symmetrical hypotrichosis and thick, myxedematous, wrinkled skin.
219
Where do lesions of calcinosis cutis associated with hyperadrenocorticism most commonly occur?
Dorsal neck, axillae and groin
220
How thick is the epidermis in hyperadrenocorticism?
1-3 nucleated cells thick
221
Mineralisation of the external root sheath can be seen in normal old dogs and in which breed?
Poodles
222
In cats, is hyperadrenocorticism most often pituitary or adrenal dependant?
Pituitary dependant
223
Which signs are associated with hyperadrenocorticism in the cat but less commonly in the dog?
Diabetes mellitus
| Skin fragility
224
What are the histopathological differences in the cat compared to the dog with hyperadrenocorticism?
Histologic lesions in the cat are similar to those in the dog; however, calcinosis cutis, and telangiectasia have not been reported.
225
What are the clinical signs of pituitary dependent pars intermedia dysfunction in the horse?
A coarse, brittle, long, shaggy haircoat (hirsutism), an abnormal shedding pattern, episodic hyperhidrosis, poor wound healing, decreased muscle tone, weight loss, and susceptibility to secondary skin infections
226
The clinical signs in pituitary dwarfism are predominantly related to which hormone deficiency?
Growth hormone (hyposomatotropism)
The most striking change is retention of the puppy haircoat.
227
Which breed of dogs are affected by an inherited form of pituitary dwarfism?
GSD
| Karelian Bear dog
228
What are the dermatological signs seen with hypersomatotropism (acromegaly) in dogs?
Thick, folded, myxedematous skin, especially on the head, neck, and distal extremities. The haircoat may be long and thick, and the nails may exhibit rapid overgrowth.
229
Which breeds are predisposed to hyperoestorgenism?
Boxer, Shetland Sheepdog, Cairn Terrier, Pekingese, Collie, and Weimaraners
230
Name breeds of dog, other than Chows and Pomeranians ,that are affected by Alopecia X
```
Keeshond
Samoyed
Siberian Husky
Alaskan Malamute
Norwegian Elkhound
American Eskimo dog
```
231
Does Alopecia X cause loss of primary or secondary hairs?
Primary
232
Normal primary hair follicles in Nordic breeds can have increased trichilemmal cornification - why does this matter?
They are predisposed to Alopecia X - initial histologic changes of Alopecia X are characterised by follicular atrophy and trichilemmal cornification in primary hairs can be quite prominent.
233
Canine recurrent flank alopecia is most commonly seen in which breeds?
Boxer, English Bulldog, Airedale Terrier, Schnauzer, and Griffon Korthal
234
What are the histological changes seen in recurrent flank alopecia?
Non-inflammatory, non-scarring follicular atrophy. Follicular infundibula are dilated and filled with keratin that can extend into the openings of the primary and secondary atrophic follicles, giving the appearance of an inverted footprint (witches feet). Sebaceous melanosis may be seen.
235
Rarely, canine recurrent flank alopecia is associated with an interface dermatitis in which breed of dog?
Boxers
See annular areas of scaling localised within the areas of alopecia.
236
During cornification, profilaggrin, located within ______ _______ of the stratum granulosum, is dephosphorylated to filaggrin
Keratohyaline granules
237
Atopic dermatitis is estimated to affect what % of dogs?
10%
238
Does IL-4 induce expression of IgE receptors on Langerhans cells, resulting in enhanced antigen presentation capability?
Yes
239
Activated mast cells release histamine and which cytokines?
L-4, IL-5, IL-6, tumor necrosis factor-α, and platelet-activating factor (PAF), that further promote inflammation
240
Eosinophils release various cytokines and which other mediators of inflammation?
Platelet-activating factor (PAF)
Eosinophil major basic protein (MBP)
Eosinophil cationic protein (ECP)
241
How do superantigens lead to non-specific activation of T cells?
Superantigens can activate large numbers of T cells nonspecifically by bridging the linkage between the class II MHC on the antigen-presenting cell (APC) and certain classes of the T-cell receptor without having to be processed and presented by the APC.
242
Can you see focal parakeratosis in dogs with AD?
Yes
243
Name recognised initiators of urticaria
```
Foods and food additives
Drugs
Biological agents
Stinging and biting arthropods
Intestinal parasites
Inhalant and contact allergens
Bacterial, fungal, and viral infections
```
244
Name non-immunological factors associated with urticaria/angioedema
Physical factors such as heat, cold, or pressure
Mast cell degranulating agents such as radio-contrast media
Agents that result in perturbation of arachidonic acid metabolism
245
What cause of urticaria has been reported in high-producing dairy Jersey and Guernsey cows?
They become sensitised to casein in their own milk (milk allergy)
246
Which part of the dermis is oedematous in urticaria?
Superficial and mid dermis
247
Which part of the dermis is oedematous in angioedema?
Deep dermis and subcutis
248
What is a hapten?
Lipid-soluble low-molecular-weight substances that become immunogenic only after penetrating the epidermis and binding covalently to an autologous structural or cell surface protein to form a complete antigen
249
Which cell is crucial to the development of allergic contact dermatitis?
Langerhans cell
250
Which Th1 cytokine, secreted by T cells, are important in allergic contact dermatitis?
IFN-gamma
| TGF-beta
251
Contact hypersensitivity has been document in which breed of dog housed in stainless steel cages?
Mexican hairless dogs
252
Can histopathology differentiate between allergic and irritant contact dermatitis?
No - histologic changes of allergic contact dermatitis are frequently indistinguishable from those caused by irritant contact dermatitis
253
Which hypersensitivity reactions are involved in FBH?
Types I and IV
254
What are the primary lesions of FBH in dogs?
Pruritus, erythema, wheals, and papules that may become crusted
255
True or false; firm alopecic nodules (“fibropruritic nodules”) may develop on the dorsal lumbosacral region secondary to self-trauma with FBH in chronically affected dogs
True
256
Other than allergic skin disease, what other diseases are likely differential diagnoses for miliary dermatitis due to FBH in cats?
Dermatophytosis, and cheyletiellosis
257
Which two types of inflammatory cell are typically seen in CH histopath with superficial or superficial and deep perivascular dermatitis?
Eosinophils and lymphocytes
258
Does pruritus associated with hormonal hypersensitivity respond well to glucocorticoids?
No - usually unresponsive
259
What is epitope spreading?
Process by which the targets of the autoimmune response do not remain fixed but drift to include other epitopes on the same protein or nearby proteins of the same tissue.
260
Which breed of horse may be predisposed to PF?
Appaloosa
261
Which inflammatory cells can predominate in PF?
Neutrophils or eosinophils
262
Can you see a lichenoid inflammatory infiltrate with PF?
Yes - rarely
263
Is deposition of IgG at intercellular bridges in all layers of the suprabasilar epidermis or in the superficial epidermis demonstrated by IF or IHC specific for PF?
No
264
What is the primary differential for PF?
Superficial bacterial folliculitis
265
How do pustules differ in size in PF compared to pyoderma?
In PF, pustules also span the interfollicular epidermis encompassing multiple follicles, whereas in superficial folliculitis pustules are more likely to be centered on single follicles.
Impetigo does not involve hair follicles, whereas PF may.
266
PV has been reported in which species?
Dog, cat, horse, goat, monkey, and llama
267
In PV, firm sliding pressure to adjacent unaffected skin may induce fresh vesicle formation or dislodge the skin - what is this called?
Nikolsky sign
268
Can you see corneal ulceration with PV?
Yes
269
What do basal keratinocytes look like in PV?
Rows of tombstones
270
What are the typical signs of PNP on histopathology?
Combination of EM and PV
Lymphohistiocytic, lichenoid interface dermatitis, and apoptosis of keratinocytes with lymphocytic satellitosis throughout the epidermis are characteristic.
271
Do the ulcerations seen in MMP heal with scarring?
Yes
272
At which body sites do you typically see MMP in dogs?
```
Nasal planum
Medial canthus
Oral cavity
Ear canals
Genitalia
```
273
Do you see acanthocytes with MMP?
No
274
Does UV light exacerbate bullous pemphigoid?
Yes
275
Where does separation and blister formation occur in bullous pemphigoid?
Lamina lucida
276
What are histopathological differentials for bullous pemphigoid?
```
PV
VCLE
MMP
EBA
TEN
Thermal burns
```
277
What is the target in linear immunoglobulin A disease?
LAD-1 = the processed extra- cellular domain of type XVII collagen
278
What is the target in epidermolysis bullosa acquisita?
Collagen VII
279
What are the clinical signs of EBA?
Erythematous and urticarial eruption with vesicles, bullae, or ulcerations arising in areas subject to friction, including oral ulcerations.
280
What is associated with dermoepidermal separation in EBA?
Marked neutrophilic inflammation in the superficial dermis and within vesicles and bullae
281
Does cutaneous lupus in animals precede SLE as it can in people?
Typically no
282
Which veterinary species have been documented with SLE?
Dogs, cats and horses
283
Name three common manifestations of SLE in veterinary species
```
Polyarthritis
Thrombocytopenia
Fever of unknown origin
Anemia
Stomatitis
Glomerulonephritis
```
284
What are the key histologic lesions of cutaneous lesions in SLE?
- A cell-poor to lichenoid interface dermatitis with hydropic degeneration of basal cells
- A lymphohistiocytic infiltrate at the dermoepidermal junction
- Subepidermal vacuolar change
- Apoptosis of basal keratinocytes and pigmentary incontinence
285
IgG against which structure have been demonstrated in dogs and people with cutaneous signs of SLE?
Collagen VII
286
What are the histologic findings in DLE in dogs?
Lichenoid lymphoplasmacytic interface dermatitis with pigmentary incontinence, mild vacuolar change in the basal cell layer, and a few individually necrotic basal keratinocytes
287
Histopath of DLE can be difficult to distinguish from MCP; how are they distinguished clinically?
Mucocutaneous pyoderma generally affects the junctions of the alar folds and haired skin rather than the entire nasal planum
288
How do you differentiate MCP from DLE on histopath?
Mucocutaneous pyoderma lacks evidence of basal cell damage and is predominantly plasmacytic
289
What is the histopath of ECLE?
- Interface reaction characterised by a sparse to mild lymphocytic superficial dermal inflammatory infiltrate
- Basal keratinocyte vacuolar change with individual basal keratinocyte necrosis
- Dermoepidermal clefting
- Pigmentary incontinence
- Marked orthokeratotic hyperkeratosis
290
Are the hair follicles affected in ECLE?
The interface reaction affects outer root sheaths, and may be associated with patchy (not complete) sebaceous gland loss
291
What is the main differential for ECLE?
EM
292
Drug eruptions resembling bullous pemphigoid (clinically and histologically) have been reported with which drug?
Triamcinolone
293
Define cryopathies
Cold-related hypersensitivity syndromes that include cold agglutinin disease, a condition in which erythrocyte autoantibodies react at lower temperatures to produce microvascular thrombosis in superficial dermal vessels (most common type in dogs and cats)
294
TEN has been reported with which infectious agents?
- Mycoplasma bovis in calves
- Parvovirus in dogs
- Equine herpes virus 5 in a horse
295
What mediates apoptosis in SJS/TEN?
- Granzyme (enters keratinocytes through transient pores induced by perforin)
- FAS-ligand
- TNF-alpha
296
What type of hyperkeratosis do you see with 'old dog' EM?
Parakeratosis
297
Cutaneous vasculitis is most often seen in which veterinary species?
Dog and horse
| ~50% are idiopathic
298
Which cell type in vasculitis is most suggestive of a type III immune complex hypersensitivity?
Neutrophils
299
Which cell type in vasculitis is most suggestive of a type I hypersensitivity?
Eosinophils
300
In nasal arteritis, deep dermal arteries and arterioles have a sub- endothelial spindle cell proliferation with fibrosis and deposition of what?
Mucinous matrix (Alcian blue +ve)
301
Equine purpura hemorrhagica is an acute, usually streptococcal infection (strangles)-associated, leukocytoclastic vasculitis characterized clinically by which lesions?
Urticaria and extensive oedema of the distal limbs, ventrum, and head. These swellings may progress to exudation and sloughing.
302
Cutaneous vasculitis in pigs is most commonly associated with ________ infection
Erysipelothrix rhusiopathiae
303
The physical structure of amyloid gives it special properties, such as _______ birefringence when Congo red–stained sections are polarized.
apple-green
304
There may be familial tendency towards cutaneous amyloidosis in which breeds of cat?
Abyssinian and Siamese
305
Canine distemper virus is associated with nasodigital hyperkeratosis, so-called “hard pad” disease, and what other skin lesions?
Pustular dermatitis
306
A few poxviruses are associated with hyperplastic or neoplastic conditions, such as what?
- Molluscum contagiosum in horses
| - Shope fibroma of rabbits
307
Name two parapoxviruses
1. Orf (contagious pustular dermatitis)
2. Pseudocowpox
3. Bovine papular stomatitis
4. Parapoxvirus of red deer
308
Name two orthopoxvirses
1. Cowpox
2. Vaccinia
3. Horsepox
4. Camelpox
5. Ectromelia virus
6. Monkeypox
309
What is an important virulence factor in the pathogenesis of orf?
Viral vascular endothelial growth factor
310
Orf lesions on the limbs typically involve which areas?
Coronet, interdigital cleft, and bulb of the heels
311
Which breed of goat has been reported with a severe and persistent form of orf?
Boer
312
What is the characteristic skin lesion in pseudocowpox infection?
Horseshoe shaped crust
313
Which poxvirus causes multiple, slightly raised, smooth to slightly roughened, white and shiny, 2-8 mm papules that may occur anywhere on the body but seem to occur more frequently on the neck, chest, shoulders, limbs, and inguinal region of horses?
Molluscum contagiosum virus
314
Skin biopsy from a horse; arrows point at large intracytoplasmic inclusion bodies. What is the diagnosis?
Molluscum contagiosum virus
315
What are the clinical signs of lumpy skin disease (capripoxvirus) in cattle?
Multiple, well-circumscribed skin nodules, accompanied by fever, ventral oedema, and generalised lymphadenopathy.
316
Which cells contain typical pox inclusion bodies in lumpy skin disease in cattle?
- Endothelial cells
- Pericytes
- Keratinocytes
- Macrophages
- Fibroblasts
317
What is the vector for swinepox virus in pigs?
Haematopinus suis (mechanical vector)
318
What type of virus are herpes viruses?
Enveloped DNA viruses
319
What disease does bovine herpesvirus 2 cause?
Bovine mammillitis and pseudolumpy skin disease
320
Is teat trauma necessary for bovine herpesvirus 2 infection?
Yes - from milking and biting flies (Stomoxys calcitrans)
321
What does equine herpesvirus 3 cause?
Coital exanthema
322
Equine herpesvirus 5 has been reported with clinical and histopathological signs resembling which disease?
EM
- Nonpruritic, multifocal, pustular dermatitis around the eyes, nostrils, and muzzle.
- Histologically, there was interface dermatitis with apoptotic keratinocytes and intranuclear inclusions within the stratum spinosum and stratum granulosum.
323
What are differentials for feline herpes virus 1 infection?
Mosquito bite hypersensitivity
| EGC
324
A nonpruritic generalized skin disorder characterized by a papulocrustous eruption with alopecia and scaling most severe on the head and limbs has been described in 3 FIV or FeLV positive cats?
FIV
Microscopically, there was hydropic interface dermatitis with occasional giant cells and pale basal epidermal cells. Degenerative mucinotic mural folliculitis is described rarely in cats infected with FIV
325
Virulent systemic calicivirus has been associated with which cutaneous signs in cats?
- Facial and paw edema and with ulcers and crusting of the skin of the nose, lips, pinnae, periocular region, and distal limbs.
- Cutaneous vasculitis is seen in some of these cats
326
What type of inflammation is associated with the papular eruptions seen with FIP in cats?
Pyogranulomatous perivascular to nodular dermatitis, vasculitis and folliculitis
327
What are the histopathological findings in mucocutaneous pyoderma?
- Epidermal hyperplasia with a lichenoid infiltrate of lymphocytes and plasma cells and pigmentary incontinence.
- In addition, there are moderate to large numbers of neutrophils in the epidermis and superficial dermis
- The basement membrane is not obscured and hydropic degeneration and apoptosis of the stratum basale are usually not present.
328
Which bacteria cause exudative epidermitis in pigs?
S. hyicus > S. chromogenes, S. aureus or S. sciui
329
Which Staph. toxins can digest desmoglein-1?
Exfoliative toxins
330
Which age group of pigs are most severely affected by exudative epidermitis?
Acute form occurs in piglets of a few days old
331
What do you see on histopath of exudative epidermitis in pigs?
1. Subcorneal vesicular to pustular dermatitis.
2. Extension of infection to hair follicles results in a superficial purulent luminal folliculitis.
3. In fully developed lesions, the skin is covered with a thick crust composed of orthokeratotic and parakeratotic keratin, lakes of serum, accumulations of neutrophils, necrotic debris, and microcolonies of gram-positive cocci.
4. The epidermis is variably acanthotic and rete ridges are elongated.
5. Cells in the outer stratum spinosum exhibit variable intracellular oedema.
6. Neutrophilic exocytosis
7. Neutrophilic perivascular to interstitial infiltrate
332
What type of bacteria is Dermatophilus congolensis?
Actinomycete - Gram +ve, facultative anaerobic filamentous cocci
333
Dermatophilus congolensis zoospores are attracted to the low ______ concentration of the normal epidermis, and there they germinate to form filaments that invade the viable epidermis and outer root sheaths of hair follicles
carbon dioxide
334
How do you describe the crusts in dermatophilosis?
thick laminar and parakeratotic, alternating with layers of degenerate neutrophils, serum and bacterial filaments
335
Which ectoparasite infestation is a risk factor for dermatophilosis in cattle and goats?
Ticks
336
What are the skin lesions of dermatophilosis in cats?
Draining nodules involving, or in the area of, the popliteal lymph nodes or the subcutaneous tissue of a paw and masses on the tongue
337
In fleece rot, what discolours the wool?
Chromogenes produced by Pseudomonas spp.
338
What do you see on histopathology of fleece rot?
Epidermal pustules and superficial suppurative luminal folliculitis
339
Where do you find haemorrhagic bullae on histopath of deep pyoderma?
Hemorrhagic bullae consist of large pustules with hemorrhage in the interfollicular dermis
340
Which inflammatory cells make up a trichogranuloma?
- MNGCs
- Epitheliod macrophages
- Neutrophils
- Eosinophils around fragments of hair
341
Name another bacteria, other than Staph., that causes folliculitis in horses
Corynebacterium pseudotuberculosis
342
Name two bacteria than produce gas in abscesses/cellulitis (emphysematous)
Clostridium spp.
| Bacteroides spp.
343
What type of necrosis is seen in abscesses?
Liquefactive
344
What causes 'big head' or 'gas gangrene'?
Clostridium spp. infection
345
What causes ulcerative lymphangitis in horses and caseous lymphadenitis in sheep?
Corynebacterium pseudotuberculosis
346
What causes ulcerative lymphangitis in cattle and goats?
Trueperella pyogenes infection
347
Which bacteria have been isolated from necrotising fasciitis?
Strep. canis >> Staph. pseudintermedius and E. coli
348
What are the histopath findings in necrotising fasciitis?
Severe necrosis, suppuration, fibrinous exudation, and hemorrhage of the dermis and subcutaneous fat, fascia, and muscle.
In some instances, the epidermis and superficial dermis are infarcted as a result of thrombosis of dermal and subcutaneous blood vessels. Colonies of bacterial cocci may be evident in the inflamed subcutaneous tissue.
349
What are the histopathological findings in toxic shock syndrome?
- Epidermal and follicular epithelial spongiosis, with individual keratinocyte necrosis (apoptosis) associated with neutrophils and occasionally eosinophils surrounding the necrotic cells.
- There may also be suppurative epidermitis, crusts, and confluent epidermal necrosis.
- In the dermis, there is oedema, extravasation of erythrocytes, and variable perivascular neutrophils and fewer eosinophils
350
Which bacteria have been associated with toxic shock syndrome in dogs?
Strep. canis
| Staph. pseud
351
What causes melioidosis?
Burkholderia pseudomallei
352
What causes Glanders?
Burkholderia mallei - the cutaneous form is called farcy and skin lesions include nodules forming chains along lymphatics, ulceration, and exudation
353
Nocardia are facultative intracellular bacteria; what are the virulence factors?
- Complex cell wall lipids and resistance to phagocytosis
| - Can invade blood vessels and cause vascular necrosis and ischaemia
354
What is a differential for Nocardia panniculitis in cats?
Atypical/rapidly growing mycobacteria
355
What do you need to be present for an actinomycotic mycetoma?
1. Tumefaction (swelling)
2. Draining tracts
3. Tissue grains
356
Is fibrosis more common and severe in actinomycosis or nocardiosis?
Actinomycosis
357
What type of culture do you need for Actinomyces and Nocardia?
```
Actinomyces = anaerobic
Nocardia = aerobic
```
358
Failure to regrow hair after clipping is a unique feature of disseminated MAC infection in ______ cats.
Abyssinian
359
How readily are mycobacteria seen with atypical mycobacterial infection?
- Organisms are characteristically rare and difficult to find but are usually located in small clumps within the clear vacuoles
- Small numbers of organisms may also be found within macrophages
360
What do you see in lepromatous leprosy?
- Nodular-to-diffuse dermal to subcutaneous granulomatous inflammation without necrosis and with large numbers of intracellular acid-fast bacilli.
- These large granulomas are composed of solid sheets of large, pale, foamy epithelioid macrophages with smaller numbers of multinucleated histiocytic giant cells often containing bacilli.
- Indicative of a poor host immune response
361
What do you see in tuberculoid leprosy?
- Dermal to subcutaneous granulomas with central caseous necrosis surrounded by a zone of lymphocytes.
- Few to moderate numbers of acid-fast bacilli are generally limited to the areas of necrosis
362
What is a differential for lepromatous leprosy?
Xanthoma/xanthogranuloma
363
Which mycobacteria weakly stains with haematoxylin?
M. visibile
364
What are the histopath findings in canine leproid granuloma?
- Nodular- to-diffuse pyogranulomatous inflammation composed of epithelioid macrophages, Langerhans-type giant cells with scattered neutrophils, plasma cells, and small numbers of lymphocytes.
- The number and morphology of the acid-fast bacilli is highly variable.
365
What is a bacterial pseudomycetoma?
A chronic infection caused by nonfilamentous bacteria that form colonies visible as tissue grains or granules within lesions.
366
Which bacteria are most commonly involved in bacterial pseudomycetoma?
Coag +ve Staph.
367
Which special stains can help visualise bacteria in pseudomycetoma?
Gram and Brown-Brenn
368
With Gram staining, what colour are +ve and -ve bacteria?
Gram +ve = purple
| Gram -ve = pink/red
369
Necrotizing pododermatitis in horses is caused by which bacteria?
Fusobacterium necrophorum
- wet humid conditions
- leukotoxin = main virulence factor
- soft, blackened frog with foul odour
370
Fusobacterium necrophorum can be isolated from bovine and ovine interdigital dermatitis with which other bacteria?
```
Cattle = Prevotella melaninogenica
Sheep = Trueperella pyogenes
```
371
Contagious footrot in sheep, cattle and goats is caused by which bacteria?
Dichelobacter nodusus
| - F. necrophorum plays an important synergistic role in infection
372
Skin lesions during systemic bacterial infection are often a result of what type of pathology?
Vasculitis and/or thrombosis
373
What are the three forms of erysipelas in pigs?
Zoonotic!
1. Acute erysipelas = signs of septicemia and sudden death; depression, anorexia, lameness, and blue-to-purple discolouration of the skin, especially the abdomen, pinnae, and legs. Pink to red macules and papules may be seen.
2. Subacute = do not appear sick; have erythematous papules and wheals that enlarge to form square, rectangular, or rhomboid plaques.
3. Chronic = necrosis and sloughing of the plaques, resulting in black, dry, firm areas of skin that peel away to reveal ulcers. Distal extremities may slough.
374
What are the main histopath features of erysipelas?
Marked dermal congestion, neutrophilic vasculitis, cutaneous necrosis, and suppurative hydradenitis
375
Gangrene of the distal extremities, tail and pinnae due to vascular thrombosis in calves is associated with which systemic bacterial infection?
Salmonella enterica ser. Dublin
376
What cutaneous signs are reported in dogs with Bartonella?
1. Pyogranulomatous nodules or panniculitis
| 2. Angiomatosis (multifocal proliferations of capillaries lined by plump endothelial cells and fibrinoid degeneration)
377
What is the characteristic lesion of candidiasis?
Sharply delineated ulcers with erythematous borders and a malodorous surface with moist grey-white exudate
378
Is dermatophytosis more common in goats or sheep?
Goats
379
Which dermatophytes affect haired and woolled areas of sheep?
```
Haired = T. verrucosum
Woolled = M. canis and M. gypseum
```
380
What is the most common dermatophyte in horses?
T. equinum
381
Name three uncommon presentations of M. canis infection in cats
1. Miliary dermatitis
2. Widespread pruritic exfoliative erythroderma
3. Recurrent OE
4. Asymmetrical paronychia or onychodysplasia
5. PF like signs (crusting over bridge of nose, pinnae and paronychia)
382
Is Spendore-Hoeppli reaction more pronounced in dermatophytic pseudomycetomas or mycetomas?
Dermatophytic pseudomycetomas
383
```
Phaeohyphomycosis has been reported most frequently in which species?
Horses
Dogs
Cats
Goats
Cattle
```
Cats
384
Where do lesions of phaeohyphomycosis in cats most often occur?
Usually single and occur most commonly on the face (nose and pinnae) and paws
Often multiple in other veterinary species!
385
What is the histopathological difference between phaeohyphomycosis and mycetomas involving pigmented fungi?
1. The fungi in mycetomas form discrete organized granules, whereas those of phaeohyphomycosis appear as individual hyphae and small aggregates scattered throughout the lesion
2. Fungal elements of phaeohyphomycosis are frequently intracellular within epithelioid macrophages and MNGCs; granules of mycetomas are nearly always extracellular
386
Is sporotrichosis zoonotic?
Yes - from cats to humans
387
What are the three clinical forms of sporotrichosis?
1. Primary cutaneous
2. Cutaneous-lymphatic
3. Extracutaneous / disseminated
388
Can you see asteroid bodies/Splendore-Hoeppli material with sporotrichosis?
Yes - variable
389
Name two oomycetes
Pythium insidiosum
| Lagenidium spp.
390
What are oomycetes?
Aquatic dimorphic water moulds
391
How does Pythium differ from fungal organisms?
Cell wall = cellulose and beta-glucan (not chitin!)
| Cytoplasmic membrane = no ergosterol!
392
What is the infective stage of Pythium?
A biflagellate zoospore - released seasonally in warm weather and moisture
393
Cutaneous pythiosis is most commonly reported in which species?
Horse
| GI more common in dogs
394
What lesion of pythiosis is unique to the horse?
Characteristic grey-white to pale yellow coral-like concretions (called leeches or kunkers) that may be extruded at the skin surface
395
Is pythiosis pruritic?
Yes - extremely in horses
| Variably in dogs
396
What is a common clinpath abnormality with pythiosis?
Eosinophilia
397
Which two inflammatory patterns are seen in canine cutaneous pythiosis?
1. Necro-eosinophilic (negatively stained hyphae more commonly seen)
2. Granulomatous
398
The hyphae of Pythium in tissue look similar to which other organisms?
Basidiobolus
| Conidiobolus
399
Lagenidiosis has been reported in which veterinary species?
Dogs
400
Name three zygomycetes
```
Mucorales = Rhizopus, Mucor
Entomophthorales = Basidiobolus and Conidiobolus
```
401
Is zygomycosis contagious?
No - from the environment
402
```
Piedraia hortae (“____ piedra”)
Trichosporon beigelii (“____ piedra”)
```
```
Piedraia hortae (“black piedra”)
Trichosporon beigelii (“white piedra”)
```
403
Name three cutaneous protozoal infections
```
Besnoitia
Leishmania
Caryospora
Neospora
Toxoplasma
Sarcocystis
Babesia
```
404
The acute phase of besnoitiosis in cattle can be confused with which other diseases?
Bluetonue and malignant catarrhal fever
| - fever, generalized oedema, weakness, anorexia, and lymphadenopathy
405
What are the clinical signs of chronic besnoitiosis in cattle?
Alopecia; marked thickening and folding of the skin, especially around the neck, shoulders, and rump; scaling; exudation and fissuring
406
What does the parasitophorous vacuole contain in besnoitiosis?
Myriad of tighlty packed basophilic, crescentic bradyzoites
407
What are the three most common histopath patterns seen in canine leishmaniasis?
Granulomatous perifolliculitis, superficial and deep perivascular dermatitis, and interstitial dermatitis
408
Sebaceous adenitis occurs in what % of canine leishmaniasis cases?
~45%
409
How do you differentiate Neospora from Toxoplasma histopathologically?
IHC, electron microscopy or PCR
410
What do you see histologically with Babesia?
Leukocytoclastic vasculitis with or without vascular necrosis
411
What type of organism is Prototheca?
Algae
412
What are the clinical signs of protothecosis?
- Single to multiple papules and nodules, often over pressure points or nodules and ulcerations involving mucocutaneous junctions (especially nostrils), scrotum, and pawpads
- Nasal planum depigmentation may be striking
413
Which special stains can help identify Prototheca?
GMS, PAS, Gridley
414
What shape do arthropod bites and stings look like on histopath?
A triangular area of necrosis and inflammation with one point of the triangle in the deep dermis or panniculus
415
Name two species of warbles
Hypoderma (bovis and lineatum) - cattle, horses, sheep, goat
| Przhevalskiana silenus - sheep and goats
416
'Butcher's jelly' is the green gelatinous material seen in fascial planes due to warble larval migration - what makes it green?
Eosinophils
417
Haematobia irritans can cause what clinical signs in horses?
Seasonal ventral midline dermatitis
418
Haematobia irritans (horn fly) require what to lay eggs?
Cow faeces
419
Which body areas of the horse do these lice prefer?
Haematopinus asini
Werneckiella (Damalinia) equi
Haematopinus asini = head, neck, back, thighs and fetlocks
| Werneckiella (Damalinia) equi= head, mane, tail base
420
Which louse is found on cats?
Felicola subrostratus
421
Which lice are found on dogs?
Linognathus setosus
Heterodoxus spiniger
Trichodectes canis
422
What is the most important ectoparasite of pigs?
Sarcoptes scabiei
423
How pruritic is sarcoptic mange in cats?
Variable - may not be pruritic as in Norwegian (crusted) scabies in people
424
What are the typical histopath findings with Notoedres infestation?
- Hyperplastic to spongiotic epidermis
- Eosinophil-rich, superficial perivascular to interstitial dermatitis
- Marked focal parakeratosis
- Mite segments may be found within the superficial epidermis
425
Which species do Psoroptes ovis and Psoroptes cuniculi affect?
Psoroptes ovis = sheep, cattle, goats, rabbits, horses
| Psoroptes cuniculi = ear mite of rabbits, horses, donkeys, mules, goats and sheep
426
Psoroptes mites are sarcoptic, do they burrow?
No - complete their life cycle on the skin surface
427
When is psoroptic mange most prevalent in sheep and cattle?
Autumn/winter
428
Which species are affected by:
Cheyletiella parasitivorax
Cheyletiella yasguri
Cheyletiella blakei
Cheyletiella parasitivorax = rabbits
Cheyletiella yasguri = dogs
Cheyletiella blakei = cats
Weak host specificity!
429
How do you differentiate Cheyletiella eggs from louse eggs? Both are attached to hairs.
Cheyletiella eggs are not operculated and are smaller
430
How long is the life cycle and off-host survival of Cheyletiella?
Life cycle = 21 days
| Off host survival = 10-30 days
431
What are the early histopath lesions of demodicosis?
Lymphocytic mural interface folliculitis
432
What are the typical histopath findings with D. injai?
- Marked sebaceous gland hyperplasia
- Few mites
- Lymphoplasmacytic periadnexal dermatitis
- Pyogranulomatous sebaceous adenitis
433
Which body sites are most often affected by D. gatoi in cats?
Self-induced alopecia on the ventral abdomen, thorax and medial aspect of the limbs
434
What do the non-pruritic, non-painful nodules of demodicosis in cattle look like histopathologically?
Follicular cysts lined by flattened squamous epithelium and filled with keratin squames and large numbers of Demodex mites
435
In horses, at which body sites are D. caballi and D. equi typically found?
D. caballi = eyelids and muzzle
| D. equi = body
436
Demodex phylloides is found on which animal?
Pigs
437
What type of mite is Straelensia cynotis?
Trombiculid
438
What are the clinical signs of Straelensia cynotis infestation in dogs?
- Multiple alopecic erythematous papules and nodules over the head, neck, dorsum, extremities, and lumbar regions
- Pustules, purulent exudate, crusts, and ulcerations are sometimes very extensive
- Usually not pruritic
439
What are the histopath lesions of Straelensia cynotis infestation in dogs?
1. Hair follicles are dilated, and most contain an intrafollicular larval mite.
2. Marked pseudoepitheliomatous hyperplasia and perifollicular mucinosis are considered pathognomonic.
3. Eosinophilic, sometimes mineralized, dense and amorphous material often surrounds larvae.
4. Dermal inflammation is generally mild, consisting of lymphocytes, plasma cells, and a few mast cells. Eosinophils are rare.
5. There is a striking proliferation of vascular channels surrounding some lesions and occasionally replacing hyperplastic follicular epithelium.
440
What is the cat fur mite called?
Lynxacarus radovsky
441
What are the clinical lesions of hookworm dermatitis?
Pruritic, red papules on parts of the body exposed to the ground
- no visible entry point
442
What causes habronemiasis?
Habronema majus (microstoma)
Habronema muscae
Draschia megastoma
443
Which flies transit Habronema?
Musca spp.
| Stomoxys calcitrans
444
What are characteristic features of habronemiasis?
1. Multifocal coagulative necrosis with dense aggregates of degranulating eosinophils
2. In 50% of cases, nematode larvae are found within the necrotic foci
3. Palisading granulomas containing epithelioid macrophages and multinucleated histiocytic giant cells
4. Larvae are usually degenerate and sometimes mineralized
445
Which test can help diagnose habronemiasis if larvae are not visible on biopsy?
PCR
446
Which nematode lives in cystic diverticula from hair follicles?
Stephanofilaria spp.
447
What are the intermediate hosts for Onchocerca cervicalis, O. reticulata, and O. gutturosa?
Culicoides for all three
+ Simulium for O. gutturosa
+ mosquitos for O. cervicalis
448
What is a characteristic clinical lesion of onchocerciasis?
An annular lesion in the center of the forehead
449
What are the clinical signs of Pelodora dermatitis?
- Moderate-marked pruritus
| - Erythema, papules, pustules excoriations, scaling, exudation, crusting, alopecia, lichenification
450
Where are Pelodora found in the skin?
The hair follicles or free in the dermis
451
What are the histopath findings in cutaneous infections with D. immitis?
Angiocentric and pyogranulomatous dermatitis with intralesional microfilariae
452
Canine juvenile cellulitis is most common in which breeds?
Golden retriever, dachshund, gordon setter, Labrador and Lhasa apso
453
What are the clinical lesions of canine juvenile cellulitis?
Papules, pustules, crusts, alopecia, and very marked oedema
454
What happens to the hair follicles in paraneoplastic alopecia in cats (pancreatic or bile duct carcinomas)?
Hair follicles are diffusely in telogen and appear miniaturized.
455
Why does the skin look glistening in paraneoplastic alopecia in cats?
Missing stratum corneum
456
What are the histopath findings in thymoma-associated exfoliataive dermatitis in cats?
1. cell-poor to cell-rich predominantly lymphocytic interface dermatitis
2. mild transepidermal and follicular apoptosis
3. marked orthokeratotic hyperkeratosis, with patchy parakeratotic hyperkeratosis
457
Canine eosinophilic granulomas are rare; what are the clinical signs and typical breed affected?
- Siberian Huskies <3 years, males
| - Nodules or plaques most common in the mouth or on the tongue
458
Name three causes of eosinophilic granulomas in horses
1. IBH
2. Atopy
3. Food allergy
4. Localised trauma
5. Silicone coated needles
6. Close clipping (free hair in the dermis)
459
Which breed of horse is most often affected with unilateral papular dermatosis?
Quarter horse
460
What are the histpath lesions of unilateral papular dermatosis in the horse?
- Eosinophilic folliculitis and furunculosis
| - Eosinophilic granulomas and collagen flame figures may be present in the surrounding dermis
461
Multisystemic, eosinophilic, epitheliotropic disease in the horse typically occurs at what age and breed?
3-4 years
Standardbreds and Thoroughbred over-represented
462
What are the clinical signs of multisystemic, eosinophilic, epitheliotropic
disease in the horse?
1. Severe weight loss
2. Pitting oedema
3. Exudative, exfoliative dermatitis that usually originates at the coronary bands or head and becomes generalized.
4. Chronically, there is scaling, crusting, and alopecia.
5. Early findings include well-demarcated ulcers on the coronary bands, muzzle, mucocutaneous junctions, and mouth.
6. Vesicles, bullae, and wheals are rarely noted.
7. Pruritus is variable
8. ~50% have diarrhoea and pyrexia
463
Do horses with multisystemic, eosinophilic, epitheliotropic disease have eosinophilia?
Only in 14% of cases
464
Sterile eosinophilic folliculitis and furunculosis in dogs typically affects the dorsal muzzle and which other body areas?
Around the eyes, ears, and less commonly in the axillae, inguinal areas, and ventrum
465
What are the clinical lesions of sterile eosinophilic folliculitis and furunculosis in dogs?
- Sudden onset of vesicles, papules, nodules, crusts, erosions, and ulcers.
- Pruritus is variable but can be intense.
- Lesions are painful in some dogs
466
In cats, eosinophilic folliculitis and furunculosis is most often seen with which diseases?
Mosquito bite hypersensitivity
| Herpesvirus dermatitis
