Dermatology Flashcards
Pruritis
Itch - unpleasant sensation of the skin that provokes the urge to scratch
What can lead to Pruritis in dogs?
Infection
Allergies
Parasites
What are the types of allergens that cause pruritis in dogs?
Flea allergen Atopy Food hypersensitivity Verminosis/mites Contact hypersensitivity
Atopy
environmental allergen
What Ectoparasites cause pruritis in dogs?
Sarcoptes Demodecosis Secondary pyoderma Cheyletiella Lice Chiggers
What infections are the causes of pruritis in dogs?
Pyoderma - bacterial infections
Dermatophytosis
Yeasts
What is responsible for alopecia of the caudal dorsum in dogs?
Flea allergy dermatitis
What is responsible for feet licking and chewing in dogs?
Food allergy
atopy
What is responsible for alopecia of the Elbows and ears in dogs?
Sarcoptic mange
What causes seasonal pruritis?
Flea allergy
Atopy
Insect allergy
What causes non-seasonal pruritis?
Scabies Food allergy Flea allergy Atopy Secondary infections Demodecosis
What is the scale used to Grade Pruritis?
Scale 1-10
What diseases are extremely pruritic?
Scabies
Flea bite allergy
Food allergy
If pruritis came before the lesions consider:
Allergies
Scabies
If lesions showed up before the pruritis consider:
Demodecosis
Dermatophytosis
What antibiotics cause allergic reactions?
Sulfonamides
Penicillins
Cephalosporins
What is the most common cause of skin disease?
Fleas
Primary Dermatological lesions
initial eruption that develops spontaneously as a direct reflection of the underlying disease
Appear and disappear quickly
Secondary Dermatological lesions
Evolve from primary lesions or are artifacts induced by the patients or by external factors such as trauma/biting/licking and medication
Stay around for a much longer time period
What are primary skin lesions?
Macule or Patch Papule or plaque Pustule Vesicle or bulla Wheal Nodule Tumor or cyst
What are characterized as primary or secondary lesions?
Alopecia Scale Crust Follicular casts Comedo Pigmentary abnormalities
What are secondary skin lesions?
Epidermal collarette Scar Excoriation Erosion or ulcer Fissure Lichenification Callus
Macule
Flat spot (<1cm) on skin with change in skin color
Patch
Macule >1cm
Papule
Small, solid elevation in skin up to 1 cm in diameter
Plaque
Coalition of papules forming flat-topped elevation
What causes a plaque?
a Hotspot
Vesicle
Elevation of epidermis filled with clear fluid
Bulla
Vesicle > 1 cm in diameter
Wheal
Sharply delineated lesion of edema
What causes Wheals?
Hypersensitivity
Nodule
Solid raised palpable lesion > 1cm. Can include abscess (fluctuant lesion in dermis or SQ from pus)
Nodule: Tumor
Large palpable mass - neoplastic
Cyst
Epithelial lined cavity with solid or fluid material
Alopecia
Absence of hair from area where it is normally present
Scale
Accumulation of loose fragments of horny layer of skin
Crust
Accumulation of dried serum, exudate on surface of skin
Follicular casts
Accumulation of keratin and sebaceous material stuck to a hair shaft
Comedone
Dilated hair follicle filled with debris
What breed is predisposed to Comedone?
Schnauzers
What causes Comedones?
Hyperthyroidism
Hyperadrenocorticism
Epidermal Collarette
Scale arranged in circular pattern
What is an epidermal collarette associated with?
Pustule
Vesicle
Bullae
Scar
Fibrous tissue has replaced the damaged dermis or s/c tissue
Excoriation
Linear abrasion of the skin
Erosion
Shallow ulcer that does not break the basal layer
Ulcer
Break in epidermis with exposure of dermis
Fissure
Linear cleavage (crack) in the epidermis or dermis caused by disease or injury
Lichenification
Thickening and hardening of the skin, note exaggerated skin lines
Callus
A localized hyperplasia of the stratum corneum of the epidermis caused by pressure or friction.
What is a common sites of Callus formation in dogs?
Elbows
lateral hock areas
What two dermatological parasites lead to eggs in the feces?
Hookworms
Sarcoptes
What are the surface mites seen on superficial skin scrape?
Sarcoptes Notoedres Otodectes Cheyletiella Demodex gatoi in cats
What are follicular parasites?
Demodex spp.
Anagen hair
active growth phase for the hair
Telogen hair
the hair has achieved maximum growth and is dying
What can you see on Acetate tape impression smear?
bacteria
fungi
yeasts
What type of hypersensitivity is Flea Allergic Dermatitis?
Type 1 Hypersensitivity
What is the most common allergic skin condition in dogs and cats?
Flea Allergic Dermatitis
Where is Flea Allergy Dermatitis distributed?
Lumbo-sacral distribution Tail base Caudo-medial thighs Ventral abdomen Flanks
What do cats present with with Flea Allergy Dermatitis?
Miliary dermatitis
What can be seen with Flea Allergy Dermatitis?
Pruritic crusting eruption secondary erythema seborrhea excoriation pyoderma hyperpigmentation lichenification
Seborrhea
Scaly skin
What is a more definitive diagnostic test for Flea allergy dermatitis?
Flea Antigen Test Intradermal flea allergy test
What is the treatment for Flea Allergy Dermatitis?
Flea eradication
What are the three types of flea eradication products?
Knock down product
Insect growth regulator
Environmental control
What does Advantage treat?
kills adult fleas before they lay eggs and prevent eggs from being shed
What does Revolution treat?
Kills adult fleas and prevents eggs from hatching
What does Vectra 3D treat?
prevents development of flea eggs and Larvae
What does Promeris treat?
kills fleas
What type of hypersensitivity is Atopy?
Type 1 Hypersensitivity
Atopy
Allergic dermatitis
What is the most common cause of Atopy?
House Dust Mites
What are the characteristic signs of Atopy?
Pruritis
Chronic or relapsing/seasonal signs
What is the age of onset for Atopy?
4 months to 7 years
Where is Atopy distributed?
Paws Face Distal extremities elbows ventrum otitis
How do you diagnose Atopy?
Serum test (RAST and ELISA tests) Intradermal skin tests
What do Allergy tests detect?
Allergen-specific IgE
What is the gold standard for diagnosing Atopy?
Intradermal allergy testing
What are the three possible therapies for Atopy?
ASIT (Allergen-specific immunotherapy)
Allergen avoidance
Symptomatic relief
What are the two forms of allergy shots?
Subcutaneous immunotherapy
Sublingual immunotherapy
What is a weak therapy for the treatment of Atopy?
Antihistamines
Antidepressants
Essential fatty acids
Topical therapies
What is a fair therapy for the treatment of Atopy?
Skin lipid therapy
What is a strong therapy for the treatment of Atopy?
Glucocorticoids
Cyclosporine A
Oclacitinib
How does Skin Lipid complex work?
restores the epidermal barrier
What are the side effects of Corticosteroids?
PU/PD Polyphagia Weight Loss Iatrogenic hyperadrenocorticism Iatrogenic hypoadrenocorticism with sudden withdrawal Susceptible to infections Urinary incontinence Behavior changes
What is Cyclosporine A?
Anti-allergic and immunosuppressive
What are the side effects of Cyclosporine A?
V/D
exacerbates skin infections
How does Oclacitinib work?
Janus kinase inhibitor - JAK1 and JAK 3 enzymes
Decreases itching and inflammation
What are the first antihistamines used?
Hydroxyzine and Citirizine
What are the second antihistamines used?
Clemastine
What are the clinical signs associated with Adverse food reactions?
Vomiting diarrhea abdominal discomfort bloat Dermatological signs
Food idiosyncrasy
Resembles food allergy but does not involve immune system
Food poisoning
Direct non-immune response to a food or toxin
Pharmacological reaction
Drug-like or pharmacological effect of food on host
Food indiscretion
Gluttony, pica, or ingestion of indigestible material
What does Lactose intolerance cause?
diarrhea
bloating
abdominal discomfort
What fish contains histamine and vasoamine?
Mackerel
Tuna
What does Acute Food Allergy cause?
Systemic consequences
Respiratory distress
Vascular collapse
Urticaria
What are the antigens related with Food allergies?
Proteins
Glycoproteins
Carbohydrates
What are the most common food antigens in dogs and cats?
Beef protein
What food is food allergy in dogs related to?
Beef protein
What food is food allergy in cats related to?
Beef protein
Fish
What type of hypersensitivity are food allergies commonly?
Type 1 hypersensitivity
What are the clinical signs of food allergies?
Pruritis
Hyperemia
Angioedema
Local reaction in GIT: Diarrhea, Abdominal discomfort/bloating, vomiting
What is the third most common hypersensitivity skin disease?
Food Allergies
What is the age of onset for food allergies?
less than 1 year of age
What time of year does food allergies happen at?
Non-seasonal - more in summer when wet and humid
What Primary type of lesions do you see with food allergies?
local or generalized pruritis Recurrent moist dermatitis Papules Erythema Wheals Plaques/pustules
What secondary type of lesions do you see with food allergies?
Excoriation Crusting Hyperpigmentation lichenification ulcers due to deep scratches
Where are the lesions localized with food allergies on dogs?
Muzzle Ears Distal limbs Paws Axillae Groin region
Where are the lesions localized with food allergies on cats?
Head
Face
Pinnae
Neck
What clinical signs are sometimes seen with food allergies?
Vomiting
diarrhea
Colic
What is the treatment for food allergies?
Positive response to an elimination diet
How long does it take for food allergies to improve in dogs?
3 weeks
What is the biggest limitation for food allergy treatment?
Owner compliance
How do you diagnose food allergies?
Intradermal skin testing
ELISA Serology
Colonoscopy allergen provocation
Skin biopsy
What are the three options available for treatment of food allergies?
Low allergy commercial diet
Homemade hypoallergenic diet
Hydrolyzed protein diet
Hydrolyzed protein diet
Protein is hydrolyzed into small particles less than 10,000 Daltons
Urticaria
Hives
Angioedema
Swelling of the subcutaneous tissue of the neck and face
How do you treat Urticaria and Angioedema?
Remove the antigen
Injectable antihistamines
Injectable steroids
Dyspnea
What is the type of hypersensitivity for Contact Dermatitis?
Type 4 Hypersensitivity reaction
What causes contact dermatitis?
Prolonged exposure with an offending surface
What are the clinical signs of contact dermatitis?
Pruritic lesions
Hairless areas
Lips affected if food bowl is the cause
Neck lesions if the collar is the problem
How do you diagnose Contact Dermatitis?
Rule out differential
Patch Test
Histopathology
What is the treatment for Contact Dermatitis?
Identify and remove the offending allergen
What are the common ectoparasites of dogs?
Sarcoptes Demodecosis Cheyletiella Lice Chiggers
What results in intense pruritis?
Sarcoptic mange
Clinical signs of Sarcoptic mange?
Positive pinnal pedal reflex intensely pruritic poorly steroid responsive sparsely haired areas Secondary weight loss
What areas are affected by Sarcoptic mange?
Hocks
elbows
pinnal margins
ventral abdomen and chest
How do you diagnose Sarcoptic mange?
Response to treatment
Positive pinnal-pedal reflex
Fecal Flotation
How do you treat Sarcoptic mange?
Topical dips: anti-seborrheic shampoo
Topical spot on or systemic: Selamectin, Moxidectin, Ivermectin, Milbemycin, Fipronil
How is demodex transmitted?
during the first three days of life during suckling
What does Demodex cause?
Parasitic folliculitis
Clinical signs of Demodex
Focal and patchy alopecia
Pododermatitis
Inflammation between the paws
Localized Demodecosis
One to several well circumscribed erythematous, scaly, non-pruritic areas of alopecia on the face and fore-limbs
Generalized Demodecosis
less than 12 lesions Coalescing over the general body
How do you diagnose Demodecosis?
Deep Skin scrapes
Biopsy
Histopathology
What is the treatment for Localized Demodecosis?
Heals spontaneously
What is the treatment for Generalized Demodecosis?
Long term treatment of Amitraz for 3 weeks
What should you avoid with Demodecosis?
Steroids
What are the clinical signs of Cheyletiella?
Walking dandruff
Scaling
Pruritis
Papular crusts
How do you diagnose Cheyletiella?
Seen with the naked eye crawling on fur
Acetate tape test
Treatment of Cheyletiella
Topical: Shampoos, Spot-ons
Treat environments
What causes Hookworm dermatitis?
Ancylostoma
Uncinaria
What are the clinical signs of Hookworm dermatitis?
Interdigital areas areas in contact with the ground Intensely pruritic Erythema alopeica thickening
How do you diagnose Hookworm dermatitis?
Fecal flotation
Where on the body do you find Chiggers?
legs
head
abdomen
Where on the body do you find chiggers on cats?
inside the ears
How do you diagnose Chiggers?
Skin scrapes
Red color
Clinical signs
How do you treat Chiggers?
Two pyrethrin dips spaced 2 weeks apart
Topical antiparasitic drugs
What are the four types of surface pyoderma?
Pyotraumatic pyoderma
Intertrigo
Mucocutaneous pyoderma
Bacterial overgrowth
Impetigo
a condition that occurs in puppies on their ventral abdomen from bacterial overgrowth
Furunculosis
infection has broken through follicle and into the skin
Cellulitis
infection of the fat under the dermis
What is an exampled of Surface pyoderma?
Hotspot
Surface pyderma
Surface of skin
Superficial pyoderma
Epidermal layer and/or hair follicles, papules, pustules, epidermal collarettes, crusts
Deep pyoderma
Dermal layer or subcutis plus follicles. Exudation of blood and/or pus, crusting, odor ulceration, tract fistula, swelling
How do you treat surface mixed pyoderma?
Topically
How do you treat superficial staphylococcus pyoderma?
Systemic and topical
How do you treat deep pyoderma?
Systemic, long term, topical
What are the clinical signs of pyoderma?
Pustules
Papules
Crusts
How do you diagnose pyoderma?
Cytology of bacteria
Culture
When is a bacterial culture mandatory for pyoderma?
less than 50% improvement within 2 weeks of treatment New lesions Residual lesions at 6 weeks Intracellular rods on cytology History of MRSA or MRSP
What do you culture for pyoderma?
Pustules
Under crusts
Epidermal collarettes
Why is Topical therapy important?
Decreases duration of systemic Antibiotics
When do you use Benzoyl Peroxide with pyoderma?
Pyoderma with oily seborrhea or comedones
When do you use Chlorhexidine with pyoderma?
Pyoderma with dry seborrhea or normal skin/coat
Mupirocin
bacteriostatic/bacteriocidal used topically and effective against Gram-positive including MRSA
Silver Sulfadiazine
topical antibacterial used topically on wounds, burns, and ear infections including Pseudomonas
What do you use for 1st tier pyoderma therapy?
Cephalosporins
Clavamox (Amoxicillin + Clavulanic acid)
Clindamycin