Dermatology Flashcards by Corinne Perra

18month male neutered Daschund has been itching and scratching over the lumbar-sacral region for a week

Exam shows erythema, excoriation, and alopecia

What would your problem list be and DDX for this patient?

Problem list

alopecia
moderate excoriation/hyperaemia
severe pruritus

DDX

flea bite hypersensitivity
demodecosis
superficial bacterial pyoderma

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18month male neutered Daschund has been itching and scratching over the lumbar-sacral region for a week

Exam shows erythema, excoriation, and alopecia

What would your further work up include?

Skin scrape
Plucks
Smear
Fetal dirt test

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What are primary skin lesions

Initial eruption that develops as a reflection of the underlying dz

Macula/patch 
Papule/plaque 
Pustule 
Vehicle/bulla 
Wheal 
Nodule 
Tumor/cyst

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What is a secondary skin lesion?

Evolve from primary lesions or are induced by patient/external factors

Epidermal collarette 
Scar 
Excoriation 
Erosion or ulcer
Lichenification 
Callus

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What lesions can be either primary or secondary?

Alopecia 
Scale 
Crust 
Follicular casts 
Comedone 
Pigmentary abnormalities

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Flat spot <1cm on skin with change in skin colour

Macule

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Flat spot >1cm on skin with change in colour

Patch

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What are types of macules caused by bleeding into the skin ?

Purpura
Petechia
Ecchymosis

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Small solid elevation in skin up to 1cm

Papule

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Coalition of papules forming a flat topped elevation

Plaque

Hot spot -red and inflamed

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Elevation of epidermis with clear fluid (<1cm)

Vehicle

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Elevation of epidermis with clear fluid >1cm

Bulla

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Sharply delineated lesion of edema

Wheal

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Solid raised palpable lesions >1cm

These can include…?

Nodule

Abscess, cyst, tumor, or granuloma

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Absence of hair from a normally a haired area

Alopecia

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Accumulation of loose fragments of horny layer of skin

Scale

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Accumulation of dried serum, exudate on surface of skin

Crust

Accumulation of keratin and sebaceous material stuck to a hair shaft

Follicular casts

Dilated hair follicle with debris

Comedone

Scale arranged in a circular pattern?

This lesion is associated with reminants of what other lesions?

Epidermal collarette

Pustule, vesicle, or bullae

Fibrous tissue has replaced the damaged dermis or s/c tissue

Scar

Linear abrasion of the skin

Excoriation

Shallow ulcer that does not break basal layer?

Erosion

Break in epidermis with exposure of dermis

Ulcer

Linear cleavage (cracks) in the epidermis or dermis caused by disease or injury

Fissure

Thickening and hardening of the skin

Lichenification

A localized hyperplasia of the stratum corneum of the epidermis caused by pressure or friction. Common on elbows and lateral hock.

Callus

What laboratory tests are available for skin conditions?

``` Superficial/deep skin scrap Hair pluck Surface skin cytology Bacteria culture and sensitivity Comb for flea Woods lamp/ fungal culture Scotch tape test Fecal float Skin biopsy ```

What is the method used for a superficial skin scrape? | What can you find with this?

Moisten blade with liquid paraffin/ KOH/ mineral oil Scrape a large area, with 3 passes of the blade Surface mites - sarcoptes - notoedres - otodectes - cheyletiella - Demodex gatoi in cat

What is the method for a deep skin scrape and what would you be looking for?

Scrape a small focal area with dulled blade using mineral oil - induce capillary hemorrhage - squeeze follicles Follicular parasites -demodex

You do a hair pluck/trichogram. What are you looking for?

Ring worm - hyphae or spores Follicle dysplasia Surface parasite (lice or mites)

What is the method for acetate tape impression smear. What would you be able to visualize?

Scotch tape test —> onto microside —> add 1drop of diff quick Can see bacteria, fungi, or yeast

Why would you do a fecal float in a dermatology cases?

Worms can migrate through the skin — cutaneous larval migrans Hookworms - ancylostoma or uncinaria

What is the technique used for skin FNA?

21-23g needle Attached to 5ml syringe Put needle in lesion, aspirate, pull needle out a bit Redirect into another site, aspirate Release pressure on needle before withdrawing Disconnect needle from syringe, add few ml of air to syringe. Reattached to needle and express content of needle onto microscope slide

Woods lamps can produce false positives with what?

Keratin scale Soap Dyes Medications

When would you do a fungal culture?

All cats with skin dz | Dogs with inflammatory skin lesions

What lesion sampling will you do for fungal culture?

Woods lamp —> pluck hairs that fluoresce for DTM inoculation If no fluorescence —> comb with toothbrush to collect hair and scale DTM is test of choice -> must check everyday —>Can turn red if a days after a saprophytic colony grows (non-pathogenic) —> Will turn red the SAME day if a dermatophyte colony grows (pathogenic)

What are indications for skin biopsy?

``` Nodule/tumor Ulcer/vesicle Severe acute generalized dz Mucosal lesions Footpad lesions Lesions unresponsive to normal therapy ```

How will you do your skin biopsy

No prep, no scrub Gently clip hair Handle sample as little as possible Place in formalin and culture pot Can do - punch biopsy - wedge/excisional - amputation (nail or toe)

What are indications for bacterial culture and sensitively?

Cytology shows cocci and rods Or just rods Cocci but no response to right AB administered at right dose Deep pyoderma Chronic AB/GC therapy GSD pyoderma

T/F: allergy testing serology is reliable for food allergies

False