Pathology of the Integumentary System - Part 3 Flashcards
Pathologist incorporates pattern in morphological diagnosis
Perivascular dermatitis occurs when ?
inflammatory cells aggregate around blood vessels. It is nonspecific and therefore occurs with any insult
* Superficial perivascular dermatitis –
primarily hypersensitivity
Perivascular dermatitis
inflammatory cells surrounding vessels (black dots).
Looking for eosinophils; specific to Hypersensitivity Type I
List some examples of Hypersensitivity disorders
- Atopic dermatitis
- Cutaneous adverse food reaction (food allergy)
- Flea bite hypersensitivity
- Ectoparasitism
* Mange infestation (e.g. Sarcoptic mange)
Type 1 Hypersensitivity is mediated by which immunoglobulin?
IgE
Type 1 Hypersensitivity
Production of _____ antibody → immediate release of _______ amines and other mediators from ____ cells → later recruitment of _______ cells (_______)
IgE, vasoactive, mast, inflammatory, eosinophils
If you have too many mast cells on skin –> itchy!
Pruritus is an _______ sensation which provokes the desire to _____ (______).
unpleasant, scratch, itching
Pruritus in dogs and cats may manifest as?
Chewing, licking,
scratching, rubbing, and overgrooming
What causes pruritus?
Cause: Parasites, allergies, inflammation, neurogenic
conditions neoplastic
What can be seen in this image?
Acute perivascular dermatitis
Edema, erythematous papules, Wheals (see first lecture)
What can be seen in this image?
Chronic perivascular dermatitis
Alopecia, lichenification, hyperpigmentation
What can be seen in this image?
Acute perivascular dermatitis
Vascular dilation, dermal edema, spongiosis,
perivascular eosinophils
All clear spaces = edema (cardinal sign)
What can be seen in this image?
Chronic perivascular dermatitis
Epidermal hyperplasia, compact hyperkeratosis,
hyperplastic follicular infundibula, sebaceous gland
hyperplasia, apocrine gland ectasia, fibrosis
Urticaria and Angioedema are also known as?
Hives, heat bumps
What causes Urticaria and Angioedema?
Causes = drugs, biological agents,
venomous stings and etc
Urticaria and Angioedema
Wheals, erythema, edema,
variably pruritus
How long does Urticaria and Angioedema last?
Acute and last < 12-24 hrs
Histologically, Urticaria and Angioedema ?
Histologically, no lesions to
dermal edema
What can be seen in this image?
Urticaria and Angioedema
Canine atopic dermatitis is most common in what breeds?
What is this characterized by?
What is the age of onset?
- Most common cutaneous inflammatory and pruritic diseases in
dogs. - Many breeds. Terriers, retrievers, and brachycephalic dogs
- Age of onset: 1-3 years in > 70% of cases
- Generalized pruritus prior to skin lesions (seasonal [most common],
nonseasonal, or nonseasonal with seasonal worsening)
If skin lesions came before pruritus, pruritus is to a primary problem and is associated with trauma, or something else.
Canine atopic dermatitis is characterized by?
Erythema, alopecia, excoriations, hyperpigmentation, lichenification
What parts of the body are affected by canine atopic dermatitis?
Head, paws, flexor aspect of elbows, carpal and tarsal joints, paws, axilla, groin, ventrum
What can be seen in this image?
Canine atopic dermatitis
Common canine atopic dermatitis areas
Only performed when clinician wants to come up with treatment for atopic derm, not diagnose the cause.
- _______ bacterial pyoderma and ______ dermatitis are common.
Secondary, Malassezia
- Pathogenesis involves skin barrier ______ and ______ immune responses
dysfunction, dysregulated
- Diagnosis of exclusion!
- Allergy testing
- Only performed when the clinical diagnosis of
atopic dermatitis has been made by first ruling
out all other causes of pruritus/dermatitis.
- Only performed when the clinical diagnosis of
Canine food allergy (Adverse food reaction)
- An adverse reaction to a food or food additive
- ~30% of dogs are less than 1 year of age
- Non‐seasonal pruritus with variably responsive to steroid
- May have gastrointestinal signs
- Secondary infection is common
Canine food allergy (Adverse food reaction) affects which parts of the body? Can be characterized by?
- Face, pinnae, axillae, groin, paws, and perianal
- Erythema, alopecia, excoriations, scales, crusts, hyperpigmentation, and lichenification
Canine food allergy (Adverse food reaction)
Canine food allergy (Adverse food reaction)
Canine flea allergic dermatitis
1. Usually _____
2. Effects which parts of the body?
3. Characterized by?
4. Pathogenesis?
5. What should you and/or the owners do?
seasonal
Dorsal lumbar area, flanks, tail base, hindlimbs
Hypotrichosis, papules, erythematous plaques, and wheals.
Sensitization to flea saliva proteins through repeated and
intermittent flea bites
Ask about preventatives
What can be seen here?
Feline atopic skin syndrome (FASS)
* An _______ and _____ skin syndrome of cats manifested
by a _____ of reaction patterns, none of which are ____
for this syndrome, and that may be associated with ___
antibodies to ______ allergens.
inflammatory, pruritic, spectrum, specific, IgE, environmental
What can be seen here?
Countless papules
Miliary dermatitis
What can be seen here?
Self-induced alopecia (SIA
What can be seen here?
Face, head, neck pruritus (FHN)
If cat was scratched
What can be seen here?
Eosinophilic granuloma complex (EGC)
Most common on
Miliary dermatitis
Sarcoptic mange
* Common in ____ (Sarcoptes ____ var. ____)
* Highly ______, intensely ____
* Transmission is by ____ contact or via _____
* _______ mites. Lives in ____ burrowed into and under the ____ ____.
→ Do ______ skin ____, and make sure to not?
Characterized by?
dogs, scabiei, canis, contagious, pruritic, direct, fomites, Burrowing, tunnels, stratum corneum, superficial, scraping, do not rely on biopsy alone
Maculopapular eruptions, crusting and alopecia
* Perivascular eosinophilic dermatitis with
intralesional arthropods
What can be seen here?
Sarcoptic mange
What can be seen here?
Canine acariasis
What is another way to rule out ectoparasites?
What can be seen here?
Cutaneous acariasis
* Notoedres cati: cat
What can be seen here?
Cutaneous acariasis
Psoroptes ovis: sheep and goats
What can be seen here?
Cutaneous acariasis
Psoroptes cunuculi: Rabbits
What can be seen here?
Cutaneous acariasis
Chorioptes bovis: Cattle and horses
Secondary complicating factors
* Superficial trauma
* Bacteria – Staphylococcus spp. (esp. S. pseudintermedius)
* Ref: Lecture 4
* Fungi: Malassezia pachydermatis
Malassezia dermatitis
* Common in ___ and uncommon in ____
* Which dog breeds is it most common in?
* Cause: ?
* Usually secondary to?
* Effects which parts of the body?
* Characterized by?
* What is a common concurrent condition?
dogs, cats
West Highland white terriers, dachshunds, English setters, etc
Malassezia pachydermatis
underlying skin disease
Interdigital spaces, ventral neck axilla, perineal region, leg folds
Generalized alopecia, excoriations, erythema, scales → lichenification.
Concurrent otitis externa is common
What can be seen here?
Malassezia dermatitis
What can be seen here?
Malassezia dermatitis
tape on skin –> footprints, yeast
What can be seen here?
stratum corneum on bottom right
Perivascular dermatitis with parakeratosis
* Parakeratosis: indicative of ______ epidermal _____
* Examples?
increased, turnover
* Trauma
* Malassezia infection
* Zinc-responsive dermatosis
* Superficial necrolytic dermatitis (Hepatocutaneous syndrome)
Zinc-responsive dermatosis
1. Type ___ Hypersensitivity
2. Effects which breeds?
3. Caused by?
4. Is this common or uncommon?
- 1
- Siberian Husky and the Alaskan Malamute
- Inherited defect of Zn absorption or metabolism
- Common
Zinc-responsive dermatosis
1. Type ___ Hypersensitivty
2. Effects which breeds?
3. Caused by?
4. Is this common or uncommon?
- 2
- Any breed
- Zinc deficient diet, or over-
supplemented with chelating
agents (calcium, phytates) - Rare; Not seen as much because put on ?? diet
Zinc-responsive dermatosis
1. Effects which parts of the body?
2. Characterized by?
3. What commonly happens?
- Face (muzzle, periocular),
mucocutaneous junctions,
distal extremities, paw pads - Crusting, scaling, erythema,
and alopecia - Secondary infection is
common
What can be seen here?
Zinc-responsive dermatosis
What can be seen here?
Zinc-responsive dermatosis in pigs
1. Effects pigs within what age range?
2. How does this happen?
- Young pigs (2-4-month-old)
- Pigs not allowed access to soil
or not supplemented with zinc
What can be seen here?
Zinc-responsive dermatosis in pigs
Superficial necrolytic dermatitis
(NOT interchangeable with ____________ _________)
hepatocutaneous syndrome
Superficial necrolytic dermatitis
1. Affects which species? What age range?
2. Characterized by?
2. What parts of the body are affected?
3. What is this condition associated with?
4. Pathogenesis?
- Small breed geriatric dog
- Hyperkeratosis of the paw pad, bilaterally symmetrical erythema, scaling, crusting,
erosions, and ulcers - Distal limbs, perioral and periocular areas
- Associated with liver disease,
glucagonomas, diabetes mellitus
* Hypoaminoacidemia or hyperglucagonemia - Pathogenesis unknown b/c you have liver problem, depletion of amino acids which are essential for skin health.
What can be seen here?
Superficial necrolytic dermatitis
What can be seen here?
Superficial necrolytic dermatitis
Widespread nodules in liver
What can be seen here?
red = perakeratosis
white = intracellular edema
blue = basal hyperplasia
Self-assessment - Perivascular dermatitis
* What are the clinical and histologic features of perivascular dermatitis?
* What is the underlying pathogenesis for perivascular dermatitis?
* What are disease examples for
perivascular dermatitis?
Interface dermatitis
* Pathologic events target ______ ________ and ________ junction
* Involved in ?
* Type ___ hypersensitivity reaction –> attacks the cells. due to autoreactive T cells. T cells decide to attack basokeratinocyte
* Autoreactive cytotoxic ___ cells
* ______ ______ deposition
basal keratinocytes, dermoepidermal
immune dysregulation and autoimmunity
II, autoreactive, T, Immune complex
What can be seen here?
bands of cells tagged with basal keratinocytes??
What can be seen here?
basal cell degeneration where there are vacuoles
What can be seen here?
Interface dermatitis
* Vesicles, erosions or ulcers
Lupus erythematosus (LE)
* _______ disease
* Pathogenesis _____. _____ predisposition.
* Classification
* _______ LE (more common!) and ______ LE (very rare)
Autoimmune, unknown, Breed, Cutaneous, systemic, SLE with cutaneous is not common in animals? If present, SLE does not have skin involvement
Facial discoid lupus erythematosus (FDLE)
1. Which dog breed is predisposed?
2. What parts of the body are effected?
3. Characterized by?
4. Treat with?
5. Looks similar to?
6. Histological features
- German shepherd dog predisposed
- Nasal planum, dorsal muzzle
- Erythema, depigmentation, scales, crusts, erosions and ulcers with atrophy and loss the
cobblestone appearance of the nasal planum - Treat with culture-based antibiotics before biopsy
- Can look similar to mucocutaneous pyoderma
histologically - Histologic features:
* Lichenoid interface dermatitis: band of mononuclear cell infiltrate at the dermoepidermal
junction, predominately lymphocytes
* Hydropic degeneration
* Apoptosis of basal keratinocytes
* Pigmentary incontinence
- Histologic features:
What can be seen here?
Loss of cobblestone appearance
Erosions
Occurs on center of nasal planum
What can be seen here?
Example of DLE
Loss of cobblestone –> thin epidermis
What can be seen here?
Interface vs lichenoid dermatitis
Interface dermatitis
* _______ infiltrate at ______
junction WITH ______ cell death
* Example: ___
Lichenoid dermatitis
* _____ _____ dermatitis ______
keratinocyte cell death
* Example: ?
Lymphocytic, dermoepidermal, keratinocyte, DLE
Superficial, diffuse, WITHOUT, mucocutaneous pyoderm
What can be seen here?
Interface dermatitis
What can be seen here?
Lichenoid dermatitis
Erythema multiforme
1. ________ disease. _______-
mediated destruction of keratinocytes
2. Cause?
3. Effects which parts of the body?
4. Characterized by?
5. Histologically?
6. How do you treat?
- Autoimmune, Lymphocyte
- Adverse drug reaction, idiopathic, neoplasia, infections
- Trunk, often glabrous skin of the groin and axilla, mucocutaneous junctions, can be
generalized - Erythematous macules, plaques,
vesicles/bullae, ulcers, crusts - Lymphocytic interface dermatitis, transepidermal apoptotic keratinocytes,
lymphocytic satellitosis - Withdraw drug and see if animal gets better
What can be seen here?
Erythema multiforme
What can be seen here?
Erythema multiforme
Many cells invading basal?
Lymphocytes surrounding apoptic cells.
keratinocytes express part of antigen from drug, lymphocytes recognize it and tag jeratinoctye, which is why dead keratinocytes are phagocytized.
What can be seen here?
MQ usually have vacuoles in their cytoplasm b/c they are phagocytes. They differ from acantholytic cells in that acantholytic cells have a darker cytoplasm because they possess keratin.
