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