Exam 1 - Dermatology Flashcards
1
Q
What are the 3 layers of Epidermis? (inner to outer)
A
- Stratum Basale
- Stratum Spinosum
- Stratum Corneum
2
Q
Which cells produce protective pigment (in epidermis)?
A
Melanocytes in s. basale
3
Q
Which cells in epidermis have immunological function?
A
Langerhan cells in S. basale
4
Q
What are the three stages of hair follicle growth?
A
- Anagen - growing (stain very blue)
- Catagen - receding (“flame follicle”, excess tricholemmal keratin)
- Telogen - end-stage
5
Q
What glands produce and secrete sebum into follicle lumen?
A
Sebaceous glands - full of lipid so appear clear on histology stain
6
Q
What glands produce and secrete watery substance into follicle lumen?
A
Apocrine glands (sweat)
7
Q
What are the glands on foot pads called? Think of cat paw prints on cold metal table
A
Eccrine glands
8
Q
What is the dermis composed of?
A
Connective tissue of:
- Collagen
- Elastic fibers
- Blood and lymph vessels
- Nerves
- Collagen
- Muscle
9
Q
What is the subcutis composed of?
A
Fatty connective tissue that connects to deeper structures
10
Q
What are some general categories of damage?
A
Physical Injury
Infectious agents
Biochemical Derangements
Abnormalities of blood supply
11
Q
5 Cardinal Signs of Inflammation
A
Heat, Swelling, Pain, Redness, Loss of Function
12
Q
Erosion
A
Partial thickness loss of epithelium
13
Q
Ulceration
A
Full thickness loss of epithelium
14
Q
Vesicle
A
Fluid-filled space (blood, exudate, etc)
15
Q
Three gross lesions of the surface of inflamed skin
A
- Crusts
- Erosions & Ulcers
- Pustules
16
Q
Pyoderma
A
Pus in skin. Can be deep and/or superficial, focal or diffuse, and often involves hair follicles
17
Q
Folliculitis
A
Around and within follicles
18
Q
Perifolliculitis
A
Around follicles
19
Q
Furunculosis
A
Destruction of follicles
20
Q
Causes of Folliculitis
A
Bacteria, Dermatophytes, Demodex
21
Q
Normal resistance to infection (skin)
A
- Intact barrier
- Skin cannot be too wet or too dry
- Normal amount of keratin (excess creates habitat for pathogens to flourish)
- Normal flora
- Normal amount sebum
- Functioning immune system
22
Q
What are two factors that can influence pyoderma?
A
Age and Breed
e.g. GSHD, older
23
Q
What are Yorkshire terriers prone to?
A
Dermatophyte infections
24
Q
How many samples should you take when doing skin biopsy?
A
Take at least 3 samples from different areas if possible - also do NOT scrub lesion
25
What is the common cause of nodular and/or diffuse inflammation deep in skin?
Foreign bodies or fungi
26
Granuloma
Immune system is attempting to "wall-off" pathogen --> MO are present
27
Type I hypersensitivity
Ag binds to IgE --> Complexes bind to Mast Cells --> degranulation
Histological lesions: superficial perivascular inflammation with mast cells and eosinophils and dermal edema
28
Causes of Type I hypersensitivity examples
Insect bites, including fleas, are common causes
29
Atopy
Very common in Vet Med. Skin immediate hypersensitivity to inhaled or ingested allergens (or transdermal absorption)
30
Wheal (hives)
Focal skin edema
31
Excoriation
Scratch, self-trauma due to pruitis
32
Lichenification
Rough thickens skin (usually from chronic irritation)
33
Type II hypersensitivity
Small molecules bind to Ag --> cause it to appear foreign --> B cells produce IgG --> IgG attaches to cells and activates complement
Ex: Drug reaction
34
Type III hypersensitivity
Immune complexes (Ag & Ab) deposit in vessel walls --> activate complement --> initiate inflammation
Ex: serum sickness, purport with Strep equi infection
35
Type IV
Delayed hypersensitivity
Ex. Mycobacterial infections and contact dermatitis (poison ivy)
36
Histologic features in autoimmune disease
```
Lichenoid inflammation
Clefts
Pustules
Pigmentary Incontinence
Acantholysis
Single cell necrosis (dyskeratosis)
```
37
Lichenoid inflammation
Inflammation of the epidermal/dermal junction (thickened)
38
Clefts
Space between layers
39
Pustules
Areas with neutrophils --> form nodules
40
Pigmentary incontinence
Pigment that was in the basal layer has now "dropped" or "fallen" into the dermis
41
Acantholysis
Cells in the S. Spinosum that are separating from each other (very specific term)
Appear pink on H&E stain
42
Single cell necrosis (dyskeratosis)
Keratinization process not functioning properly
43
What is the most common autoimmune skin disease of dogs?
Pemphgus Foliaceous (chronic lesions)
Extensive multifocal lesions (some more acute, some more chronic)
44
Discoid Lupus Erythematosis
Aka, DLE:
Loss of pigment, can become chronic, loss of cobblestone appearance.
Exasperated by UV light (seen in CO)
45
Dermatomyositis
Long term inflammatory disorder which affects muscles (muscle weakness); skin rash can also be present
46
Sebaceous adenitis
Autoimmune condition targets sebaceous glands --> decreased sebum promotes secondary bacterial pyodermis or folliculitis
47
Alopecia areata
Seen in equine - inflammation around hair follicle bulb --> body attacks the bulbs of growing hair --> alopecia
48
Congestion
Blood accumulation within vessels
49
Edema
Fluid accumulation outside vessels
50
Vasculitis
Inflammation of the vessels; cells in the blood vessel permeate through wall and into the tissue surrounding vessel
51
What causes vasculitis?
Need history... drug reactions can cause.
Mechanical causes: compressions, animals that are down for too long, casts
Increased permeability and pro-thrombin condition
52
Abrasion
Superficial (i.e. scrape) - loss of part of epithelium (basal layer still intact - allows for healing)
53
Laceration
Cut or slice
54
Hyperkeratosis
Excess keratin
55
Ortho- (prefix)
Straight, orderly, correct
56
Orthokeratotic
Cells are in the correct form/fashion, but there is too many of them
57
Parakeratosis
Nuclei are retained
58
Acanthosis
Increase in thickness of of stratum spinosum
59
How do wounds heal?
Fibroblasts produce collagen bundles --> these are parallel to the surface of the wound (organized) --> vessels run perpendicular to wound --> CT forms new basement membrane --> granulation tissue forms --> RE-EPITHELIALIZATION of surface
60
First intention
E.g. surgical incision (easier to heal)
61
Second intention
Unable to close (more extensive wound)
62
HERDA in horses
HEREDITARY Equine Regional Dermal Asthenia
CT disorder --> weakens collagen fibers that allow the skin of the animal to stay connected to rest of animal (tenting of skin)
63
Congenital vs Hereditary
Congenital - present at birth
| Hereditary - inherited
64
Mucinosis in Sharable Peis
HEREDITARY
Mucin accumulates in deep layers of skin --> causes permanent fold or "pleats"
65
Calcinosis cutis
AQUIRED
Induced by local skin damage (iatrogenic) in susceptible animals (e.g. administering too high corticosteroid levels)
Calcium deposits in skin
66
UV-light induced changes
AQUIRED
67
Solar Elastosis
Due to chronic sun damage
Elastic fibers are damaged and leaves fragments behind
Often seen in light-faced horses
68
Aplasia
Failure of an organ or tissue to develop
69
Hypoplasia
Decreased number
70
Atrophy
Decreased size
71
Dysplasia
Wrong cell type growing (e.g squamous epithelial growing in place of respiratory epithelial)
72
Hyperplasia
Increased number
73
Neoplasia
Formation of new, abnormal growth of tissue
74
Metaplasia
Abnormal change in the nature of tissue
75
Alopecia in hypothyroid dogs
Hormone normally stimulates growth of many areas in body (including hair follicles)
Lack of hormone --> lack of hair growth
76
Color Dilution Alopecia
"Blue" colored dogs (Dobermans, weimaraners, etc)
Pigment is spilled out of the hair follicle into the dermis. Hair shafts produced are abnormal --> can lead to bacterial infections, loss of hair, etc.
77
Folliculopathy
Hair follicles have distorted morphology
78
Trichepithelioma
Benign hair follicle tumor
79
Benign squamous papilloma - growth
Fronds grow outward from surface. Swollen cells are infected with papilloma virus
80
Trichoblastoma
Benign basal cell tumor
81
Squamous Cell Carcinoma
Skin cancer originating from squamous cells (can be invasive --> metastatic)
82
Fibrosarcoma
malignant mesenchymal tumor derived from fibrous CT and characterized by presence of proliferating fibroblasts.
83
Most common equine neoplasia
Equine sarcoid - often can become ulcerated
84
Presentation of Animal: Pruitis
Usually indicates allergy or ectoparasites
85
Presentation of Animal: Alopecia
1. Endocrine diseases (hypothyroidism)
2. Secondary to inflammatory disease
3. Folliculopathy
4. Post-clipping idiopathic alopecia
86
Presentation of Animal: Erythema, pustules, crusts
Indicate inflammation. Need to determine infectious vs autoimmune causes.
87
Presentation of Animal: Lumps and bumps
Inflammation vs neoplasia
88
Hemangioma
Generally benign soft tissues and skin tumors
Hemangiosarcomas are malignant
