dermatology (NTF) Flashcards
what are the 3 layers of the skin?
(3 marks)
- epidermis
- dermis
- hypodermis
function of the epidermis?
(2 marks)
- provides waterproof barrier
- creates skin tone
function of the dermis?
(1 mark)
contains tough connective tissue, hair follicles, sweat glands
function of the hypodermis?
(1 mark)
made of fat and connective tissue
define dermatitis
(1 mark)
reddening + swelling of skin resulting from direct irritation by an external agent / allergen
define atopy
(1 mark)
localised hypersensitivity reaction to an allergen
define lesion
(1 mark)
tissue abnormality commonly caused by disease / trauma
define rash
(1 mark)
widespread eruption of lesions
define erythma
(1 mark)
reddening of skin due to increased blood supply
define pyoderma
(give example)
(1 mark)
primary skin infection, commonly staphlococcal / streptococcal infection
define pustule
(1 mark)
purulent vesicle (pus filled sac)
define plaque
(1 mark)
palpable, flat lesion, greater than 0.5mm in diameter
define lichenification
(1 mark)
thickening of the skin, commonly seen in chronic atopy
define alopecia
(1 mark)
hair loss
why might the VS want to perform a dermatology exam?
(6 marks)
- ectoparasites
- skin lesions
- pruritis
- neoplasia
- chronic dermatitis
- erythema
patient preperation for dermatology exam?
(5 marks)
- sample performed prior to administration of drug
- drug free patient 7-10 day prior to sampling
- suitable restraint
- infection contol - scabies
- skin not clipped / scrubbed / washed to prevent affecting results + more damage to skin
**
infection control of dermatological exam?
(5 marks)
- PPE
- disinfection of surfaces
- disposable equipment
- reverse barrier nursing
- clients aware of zoonosis
skin sampling techniques?
(3 marks)
- skin scrapes
- hair brushings
- cutaneous
cytology techniques
(4 marks)
- tape impressions
- hair plucks
- swabs
- skin biopsy
what are the advantages of skin scrape?
(8 marks)
- quick + easy procedure
- generally painless
- often examined in house
- minimal trauma
- RVN can perform under VS instruction
- sedation not normally required
- allows examination of full thickness + epidermis + hair follicles
- used to detect cuticulat + sub-cuticular parasites
what is a superficial skin scrape?
(1 mark)
scralpe that doesnt enter the epidermal layer of skin
when is a superfical skin scrape done?
(1 mark)
on every patient with scaly / pruritic skin
what might be found with a skin scrape?
(5 marks)
- sarcoptes scabeii
- cheyletiella
- notoedres cati
- dermatophyte spore infested hair shaft
- lice
where do sarcoptes scabeii lesions develop?
(5 marks)
- ventral chest
- abdomen
- elbows
- legs
- ears
alternative testing methods for scabies?
(4 marks)
- using ELISA technology - serology testing is carried out within an external laboratory + commonly part of an allergy profile
- looking at bodies antibodies not for scabies specifically
- more expensive and long wait
how to carry out deep skin scrape?
(2 marks)
- collection of samples from hair folliucle - result in light capillary ooze (redness)
- squeeze skin prior to get deep skin scrape
when should a deep skin scrape be done?
(3 marks)
- non-inflammatory + inflammatory alopecia
- pustules
- crusts
what can be found with a deep skin scrape?
(1 mark)
demodex sp.
what is demodex?
(2 marks)
mite often present with hair loss beneath / around eyes
live on healthy animals
clinical signs of demodex?
(2 marks)
- severe case - whole body affected
- not puritic - but secondary pyoderma is
(common in puppies when weaned - stress)
how do you choose a sample site for demodex?
(4 marks)
- head, ears and feet are commonly affected
- areas of erythmatous skin
- papules, scales or crusts#
- areas of alopecia
how to carry out microscopic evaluation?
(3 marks)
- place cover slip on slide over collected sample
- examine x4-x10 using battlement technique
- record vernier scale if parasite identifed
advantages of hair brushing?
(9 marks)
- quick and easy
- no sedation required
- patient enjoyment
- examined in house
- allows detection of coat contents
- RVN can perform under VS instruction
- non-traumatic
- inexpensive
- allows collection of cutaneous parasites
when should hairbrushing sample be done?
(3 marks)
- generally itchy patients
- patients with suspected flea infestation
- patient with excess scurf
what might be found with a hairbrushing sample?
(4 marks)
- ctenocephalides
- flea debris
- cheyletiella sp.
- dermatophytes
hair brushing sample technique?
(5 matrks)
- gloves
- stand animal over white background and restrain
- brush coat with fine toothed comb to collect debris
- place sample collected on paper into sterile container
- wetting black particles may indicate fleas
what is cheyletiella spp.?
(3 marks)
- ‘walking dandruff’
- causes skin irritation and dandruff
- zoonotic
clinical signs of cheyletiella + where it affects?
(4 marks)
- causes itchy, flaky skin
- sometimes raised spots and scabs
- commonly affects dorsal trunk
- however infestation of nasal pasage may occur
cutaneous cytology techniques?
(3 marks)
- impression smear
- aspiration smear
- sterile cotton tip
when should cutaneous cytology be carried out?
(3 marks)
- when bacterial / yeast infection is suspected (pustules, scales, crusts)
- nodules / tumours
- otitis externa
what might be found with cutaneous cytology?
(4 marks)
- cocci + rod-shaped bacteria
- inflammatory cells, eosinophils, macrophages
- malassezia
- neoplastic cells
how is an immpression smear sample carried out?
(2 marks)
- a strip of scotch tape pressed onto area of interest to collect cells and surface organisms from dry / scaly skin
- direct impression sample: glass slide pressed on to moist, exudating skin / greasy infected skin
cutaneous cytology impression sample?
(2 marks)
- insert 25-27g needle into pustule, parallel to skin to avoid involvement of deeper cells
- impression of ruptured pustule material using glass slide
sterile cotton tip impression sample?
(2 marks)
- clean cotton bud can be rolled onto surface of skin / into ear canal then roll tip into glass slide to transfer material for examiantion
- dampen cotton tip with sterile water and rolled between digits to obtain an interdigital cutaneous sample
slide evaulation of impression sample?
(3 marks)
- air dried slides stained using ‘diff quick’ technique
- tape sample adhered to slide
- both examined under oil immmersion
what is seen with cytology of impression sample?
(4 marks)
- bacteria
- fungi
- yeasts
- inflammatory cells
