Intro to derm 2 Flashcards
Major presenting signs with derm cases
- pruritus
- alopecia
- crusting
- scale
- nodules
Itchy cat, what should you 100% exclude before give steroids?
Exclude viral dermatitis e.g. pox virus. If give cat with pox virus steroids could kill it
What can present as pruritic disease of cats?
Parasites
Infections
Allergies
How do you diagnose ectoparasites?
Surface parasites:
coat brushings, flea comb wet paper, sellotape impression
Shallow and surface mites living in epidermis:
- superficial skin scrapes
Deeper mites in follicle =
- deep skin scrapes, hair plucks, biopsy
diagnosing ectoparasites can have poor sensitivity. So what?
Test treatments are good
ISOXAZOLINES e.g. stronghold plus which is selamectin and sarolaner = covers fleas, lice, decoded, scabies, cheyletiella
List surface, shallow and deeper ectoparasites
Surface = felas, lie, ticks, mites, cheyleyiella, decoded gator
Shallow = cheyletiella D. gate, sarcoptes scabei, notoires cata
Deep =
What do we treat with isoxazolines?
decoded gatoi - selamectin and sarolaner combo. Fluralaner
Demodex cati
How to carry out acetate tape sample for parasites
Which parasites is it suitable for?
In heavily haired areas clip the hair for better contact with the skin
Use a small 4-6 cm piece of tape
Apply to the area to be tested multiple times to pick up as much material as possible.
Place the tape (sticky side down) into the basophilic (last) haematology stain placed on a slide, squeegee out XS, or for the larger parasites liquid paraffin and observe at low power
This test is suitable for Neotrombicula sp, Cheyletiella spp and Demodex gatoi.
How to carry out a superficial skin scrape and what parasites it it suitable for?
Clip the hair if necessary Place liquid paraffin on the target area Scrape with a blunted blade Transfer to a slide prepared with a small amount of LP on it Place a cover slip ontop Observe at low power
Suitable for notoedres cati = crusting and v itchy, sarcoptes scabei
What diseases cause alopecia?
Any that goes down the hair follicle
Parasites = decoded cati
Infections - superficial bacterial pro, dermatophytosis
Endocrine
Allergies
Neoplasia
Clinical signs demodex cati
Comedones
Alopecia, erythema, crust, scale, pruritus, secodnary infection
How to carry our a deep skin scrape
- Deep skin scrapes should be performed whenever demodicosis is suspected
- The technique is as for superficial skin scraping, but there should be capillary ooze
- Pinch skin and squeeze HARD
roll between the fingers to maximise the yield of follicular material. - Blunted blade, take top away.
- Should see blood and haemorrhage
- These scrapes often hurt – ensure suitable analgesia and chemical restraint
ANALGESIA
then…
Take a direct impression smear cytology to identify mite and understand what is going on in terms of inflammation/ infection
How do you carry out a direct impression smear?
Take clean slide, gently squeezing, touch and
Rupture pus filled lesion or lift crust
Apply slide onto lesion several times
Pustule / papule / bulla / epidermal collarette
Dry and stain =
Info in terms of bacteria and inflam
What is paraneoplastic alopecia in cats?
Paraneoplastic syndromes are a group of rare disorders that are triggered by an abnormal immune system response to a neoplasm
unknown pathophysiology, associated with tumour affecting pancreatic bile duct
Usuallyy older cats over 10
slowly get more alopecia, not always pruritic and shiny
Thin skin +/- malassezia
Skin often waxy as common to get secondary yeast infections
Alopecia ventral body, neck, chin, inner leg, feet, nasal plant, footpads
Skin biopsy to confirm diagnosis
how to carry out a skin biopsy?
- Place the punch firmly on the skin, push hard
- twist 180˚ pushing firmly
- Do not grasp the skin, but lift the biopsy from the dermis to avoid damage
- Place the biopsy dermis down on card to stop it curling (especially important for biopsies from thin-skinned areas)
- Expect to see:
Epidermis with stratum cornea intact, dermis and maybe subcutis at bottom
