dermatology Flashcards
primary skin lesions
-happen as direct result of disease
exp:
Macule or patch
– Papule or plaque
– Pustule
– Vesicle or bulla
– Wheal
– Nodule
secondary skin lesions
– Evolve from primary lesions
– Are artifacts induced by the patient or
external trauma or medications
ex: – Epidermal
collarette
– Scar
– Excoriation
– Erosion or ulcer
-lichenification
lesions that may be primary or secondary
– Alopecia
– Scale
– Crust
– Follicular casts
– Comedones
Primary Lesion: Pustule
could be: pyderma, impetigo, folliculitis ect
Primary Lesions: Macule vs
Patchs
■ Macule:
– Circumscribed flat area of color change
– < 1 cm diameter
■ Patch:
– Circumscribed flat area of color change
– > 1 cm diameter
Hyperpigmented Macule primary lesion
Hemorrhagic Patches
-hemmorrage under skin could have macules and patches
ddx
■ Hemorrhage
– Trauma
– Vasculitis
– Vasculopathy
– Coagulopathy
Primary Lesion: Papule
Primary Lesion: Nodule
■ Nodule:
– Circumscribed solid elevation > 1 cm in diameter
– Usually extends into deeper layers of skin
■ Infiltration of inflammatory or neoplastic cells
■ Examples:
– Neoplasia
– Granulomatous inflammation
Primary Lesion: Wheal (Hives)
-could be tuffling of the hair but look at skin
Primary Lesion: Plaque
■ Plaque: Flat elevation in skin > 1 cm in diameter
■ Coalition of papules forming plaques
– Indicates chronic inflammatory disease
Primary Lesion: Vesicle and
Bulla. RARE to see in dogs and cats
■ Vesicle
– Sharply circumscribed elevation of epidermis filled with clear fluid
– < 1 cm in diameter
– Indicates: Viral, immune mediated, irritants
■ Bulla
– > 1 cm in diameter
-both rare in SA due to rupture when grooming, if you see biopsy
Secondary Lesion: Epidermal
Collarette
■ occurs secondary to papule, pustule, vesicle, bulla
■ Examples
– Pyoderma (Most common)
– Immune mediated disease
– Dermatophytosis
Secondary Lesion:
Lichenification
Secondary Lesion: Ulcers /
Erosions
■ Erosion:
– Shallow epidermal defect that does not penetrate the basal laminar zone
– Ruptured epidermal lesion; self-trauma
■ Ulcer:
– Break in continuity of epidermis with exposure of underlying dermis
biopsy: we want to take the edge* to show how epidermis transforms into erosion or ulcer. only with these two take EDGE**
Secondary Lesions:
Excoriations
Secondary Lesion: Fissure
Primary or Secondary Lesion:
Scale
dandriff = scale, we call it scale
Primary or Secondary Lesion:
Crust
■ Primary: more adhered to skin
– Zinc Responsive dermatosis
most commonly secondary: can peel that up with excaudate underneath
– Pyoderma
– Pruritus
Primary or Secondary Lesion:
Comedones
Primary
■ Feline acne
■ Endocrine dermatoses
-hypothyroidism
Secondary
■ Demodicosis
■ Dermatophytosis
Primary or Secondary Lesion:
Follicular Casts
-clumping at base of hair, will pull out easily (epulate)
-rule out secondary first then look at primary
Primary
■ Vitamin A Responsive
Dermatoses
■ Sebaceous adenitis
Secondary
■ Dermatophytosis
■ Demodicosis
Primary or Secondary Lesion:
Alopecia
■ Partial to complete loss of hair
-do we think hair fell out from inflammatory causes or non inflammatory causes (hypothyroidism)
■ Primary Lesion:
– Endocrine disease
– Follicular dysplasia
■ Secondary lesion: inflammation in the hair follicle
– Pruritus
– Bacterial folliculitis
– Dermatophytosis
Hypotrichosis
■ A form of alopecia
■ Less than normal amount of hair
-animal has hair but less than should be there
How to Approach the Dermatology Patient
- History
- Dermatologic Examination
- Otoscopic Examination
dermatology history signalment
- What breed is the patient?
- Some diseases occur more commonly in certain breeds
- Yorkshire terrier: Dermatophytosis (ringworm)
- Persian cats: Idiopathic Facial Dermatitis
Dermatology History: reason for the appointment questions
What are the signs of the skin issue?
* Why was the pet brought in?
- What are the signs of the skin disease?
- Alopecia
- Crusts
- Pruritus
- If pruritic with secondary infection
- Did the infection or pruritus occur first? did you notice rash before or after itching
pruritis
-can present in different ways
* Not just scratching!
* Ask about
* Licking
* Chewing
* Rubbing
- Pruritus: Use “itch scale”
- Important for monitoring
- Useful gauge for treatment
- Initial assessment
derm history age when problem started?
- Young animals:
- Parasites
- Allergies
- Middle aged animals
- Allergy
- Parasite
- Endocrinopathy
- Autoimmune disease
- Older animals
- Neoplasia
- Parasites
- Endocrinopathy
- Allergies – way down low on list!
derm history timeline and symptoms
- How long has the disease been present?* How has it progressed?
- Is there a seasonal component to the skin disease?
- Allergic dermatitis
- Flea Allergy Dermatitis
- Cyclic Flank Alopecia
derm history where on the body is affected?
- What parts of the body are affected?
- Where did the condition start?
derm history previous treatment and management
- Previous treatments?
- Have any been successful?
- Did the pet improve?
- Parasite control?
- Include all pets in the household
-last medication and last bath can both affect diagnostic tests
derm history diet
- What diets have been tried?
- How long was it fed?
- Any other foods, treats given?
- Any medications at the time?
- Include flea, heartworm
- Toothpaste?
if diet trial done was is successful? were all pets on trial, or could they have shared bowls, ect.
derm history other pets?
- Do other pets have clinical signs?
- Do any people have clinical signs?
derm history lifestyle
- Lifestyle of pet
- Indoor / outdoor?
- Around other animals?
- Do the people foster pets?
- If cat, FeLV / FIV status
Dermatologic Examination
-do exam in same systemic pattern
* Skin has limited reaction patterns
* History and lesion distribution can help differentiate disease
processes
-look at whole dog, see lesions and localize and think what can cause lesions in that area
- Look at the pet from afar
- Is pruritus present?
- Does the pet appear healthy?
- General attitude?
- Weight and BCS
-do a complete physical exam then a thorough dermatologic exam
- assess coat
-is there an odor? could mean infection need to use cytology to diagnose
Periocular Distribution - Dogs ddx and clinical
Differential Diagnosis
* Atopic dermatitis
* Food Allergy
* Demodicosis
* Bacterial Infection
* Malassezia dermatitis
* Dermatophytosis
* Etc.
Clinical Signs
* Alopecia
* +/- Erythema
* +/- Lichenification
* +/- Hyperpigmentation
* +/- Crusts
Perioral Distribution
Differential Diagnosis
* Demodicosis
* Atopic Dermatitis
* Malassezia dermatitis
* Mucocutaneous Pyoderma
Clinical Signs
* Alopecia
* Erythema
* +/- Fissures
* +/- Erosions
* +/- Ulcers
Dorsal Aspect of Paws - Dogs
Differential Diagnosis
* Atopic dermatitis
* Food allergy
* Demodicosis
* Sarcoptic mange
Clinical Signs
* Alopecia
* Erythema
* +/- Lichenification
* +/- Hyperpigmentation
* +/- Crusts / exudate
Ventral Interdigital Aspect of the Paws
Differential Diagnosis
* Demodicosis
* Sarcoptic mange
* Atopic dermatitis
* Food allergy
Clinical Signs
* Alopecia
* Erythema
* +/- Lichenification
* +/- Keratosebaceous exudate
derm exam areas to assess
- Paws
- Mouth
- Mucous Membranes
- Vulva / prepuce
- Ventral abdomen
- Trunk
-are the lesions symmetrical, localized, generalized?
derm exam hair coat
- How does the hair coat feel?
- Greasy?
- Coarse?
- Dry?
- Haircoat changes can indicate different conditions
- Sebaceous adenitis
- Endocrinopathy
otoscopic examination questions
- Ask specific questions!
- Is there a history of ear disease?
- Have medications been used before?
- Were there any issues with any medications?
- Are there other dermatological issues?
Otoscopic Examination outer ear
- Examine the pinna first and record changes
- Is there erythema?
- Crusts?
- Are lesions present on the distal margins?
- If worried about sarcoptic mange, is there a pinnal-pedal reflex? scratch ear see if reflex
- Palpate at the base of the ears
- Is there pain present?
- Are the ears firm?
-assess for end stage disease, otitis media - Open the mouth to see if pain is present
- Can indicate otitis media
- Are there neurological signs present?
- Anisocoria
- Head tilt, facial nerve paralysis
Otoscopic Examination in the ear with otoscope
- Visualize:
- Vertical canal
- Horizontal canal
- Tympanic membrane
- The normal ear canal may have
- Hair
- Wax
- Record any abnormalities appreciated
- Stenosis
- Exudate
- Ulceration
- Does the tympanic membrane look abnormal?
- Are the ears firm on palpation?
