Approach to alopecia 1

Question 1

What is spontaneous alopecia?

Answer 1

*No animal involvement
*Various aetiopathogeneses

Question 2

What is self induced alopecia?

Answer 2

*Animal removes hair
*Pruritus (ectoparasites, allergic skin disease
*Psychogenic (behavioural, internal pain/inflammation)

Question 3

How can you check if alopecia is self-induced or spontaneous?

Answer 3

Self induced = look for hair in teeth / litter trays
=Trichograms - shows broken hair shafts in pruritic animals

Question 4

how does inflammation cause spontaneous hair loss?

Answer 4

Inflammation within hair follicle = damaged hair = hair loss

Question 5

How would you approach diagnosis?

Answer 5

1.History
2. Physical examination - needs to be thorough
3.Differentiate spontaneous vs self-induced
4.Differentiate inflammatory vs non-inflammatory
5.List differential diagnoses
6.Make diagnostic plan

Question 6

What skin conditions are puppies predisposed to?

Answer 6

*demodicosis
*dermatophytosis
*growth hormone deficiency

Question 7

What alopecia causes are adults predisposed to?

Answer 7

Immune mediated disease (sebaceous adenitis)

Question 8

What alopecia causes are older dogs predisposed to?

Answer 8

*hypothyroidism
*Hyperadrenocorticism
*Neoplasia

Question 9

When making differential diagnoses- what should you prioritise?

Answer 9

*Common things are common
*Zoonoses - any other animals in the household

Question 10

What are the infectious agents causing inflammation causes of spontaneous alopecia?

Answer 10

*bacterial folliculitis
*dermatophytosis

Question 11

What are the parasites causing inflammation causes of spontaneous alopecia?

Answer 11

*Demodicosis
*Leishmaniasis

Question 12

What are the immune mediated causing inflammation causes of spontaneous alopecia?

Answer 12

*alopecia areata
*dermatomyositis
*sebaceous adenitis

Question 13

What is the most common cause of spontaneous alopecia in cats + dogs?

Answer 13

Bacterial folliculitis

Question 14

What is the agent causing bacterial folliculitis?

Answer 14

Staphylococcus pseudintermedius

Question 15

What can be associated with bacterial folliculitis?

Answer 15

*Pruritus
*Alopecia
*Scale
*Crust
*Deep infection

Question 16

How should you take a sample of a dry/wet lesion?

Answer 16

Dry = tape strip
wet = impression smear

Question 17

What is the most common agent causing ringworm?

Answer 17

Microsporum canis (zoophilic)

Question 18

What are less common agents causing ringworm?

Answer 18

Microsporum gypseum
Trichophyton mentagrophytes
Trichophyton benhamiae

Question 19

What animals are predisposed to ringworm?

Answer 19

*Young / Immunocompromised
*Puppies + kittens
*Persian cats
*Yorkshire + jack russel terriers

Question 20

What are reservoirs for ringworm?

Answer 20

Asymptomatic carriers

Question 21

Where are ringworm lesions mosrt common?

Answer 21

Head
Ears
Chin

Question 22

If a vet suspects ringworm what should be done?

Answer 22

Wear protective clothing to prevent contamination

Question 23

How is ringworm diagnosed?

Answer 23

*Wood’s lamp examination - apple green fluorescence of hair
*Trichography - on x100 magnification w oil immersion can see arthrospores (looks like soap bubbles)
*Culture = gold standard

Question 24

What is the mackenzie sampling technique for culture?

Answer 24

Use nylon brush to create electromagnetic charge which attracts spores
-then submit brush to lab / inoculate on fungal culture medium - RED=fungal

Question 25

What special stains can be used to detect hyphae?

Answer 25

Silver PAS

Question 26

How is ringworm treated?

Answer 26

*Spontaneously resolve (12-20wks) *Topical Tx = reduce scale = reduced contamination + shedding (miconazole / lime sulfur dip) *environmental decontamination

Question 27

What are systemic treatments of ringworm?

Answer 27

*Itraconazole - licensed in cats *Ketoconazole - licensed in dogs - can cause neurological disease

Question 28

What are the species of demodex?

Answer 28

Demodex canis (dog) Demodex injai (dog) Demodex cati (cat)

Question 29

What will happen if commensal demodex is not controlled?

Answer 29

Will proliferate + cause disease

Question 30

What are the 2 clinical syndromes of demodicosis?

Answer 30

*juvenile onset demodicosis *Adult onset demodicosis

Question 31

What is seen with juvenile onset demodicosis?

Answer 31

*Localised to generalised patches -Alopecia -Scaling -Comedones -Blue-grey hyperpigmentation -Follicular casts *+/- secondary bacterial infection *Mild cases spontaneously resolve

Question 32

Why is generalised juvenile onset demodicosis a problem?

Answer 32

Serious problem as can lead to secondary infections

Question 33

What is seen with adult onset demodicosis?

Answer 33

*Often generalised *Often secondary bacterial infection *Papules, pustules, draining sinus tracts, enlarged lymph nodes, +/-pyrexia *Pruritic or painful *Require aggressive treatment

Question 34

Is demodex cati contagious?

Answer 34

No - demodex gatoi is Demodex cati = commensal gone wrong

Question 35

What does it mean if a condition is idiopathic?

Answer 35

Can never be cured - only handled/ lifelong treatment

Question 36

How do you confirm demodicosis?

Answer 36

*positive skin scrapings *hair plucks

Question 37

When would you use biopsy to confirm demodicosis?

Answer 37

Only if skin is thickened

Question 38

When is a hair pluck useful to do?

Answer 38

On a conscious patient

Question 39

What do you need to do when doing a skin scraping and why?

Answer 39

Always squeeze the skin to bring the mite to the surface

Question 40

How would you observe demodex mites under a slide?

Answer 40

*Mount in liquid paraffin + use cover slip *Most found on x4 or x10 magnification

Question 41

What is the difference micrscopically between D. canis + D. injai + D. cati?

Answer 41

D. injai = long tail D. cati = pointy tail

Question 42

What is the treatment of demidicosis?

Answer 42

*clip long haired animals + bathe to remove debris *treat 2* bacterial infection *Treat underlying immunosuppression *Imidacloprid / moxidectin *isoxazoline - afoxolaner / flurolaner

Question 43

Why do they advise spaying dogs with juvenile onset demodicosis?

Answer 43

*increased chance of disease in offspring *periparturient reduction in immunity can result in return of disease

Question 44

How would you treat demodicosis in cats?

Answer 44

*Isoxazolines - Flurolaner *Treat underlying disease

Question 45

How would you perform a biopsy if you suspected non-inflammatory alopecia?

Answer 45

Take a biopsy of the full alopecia, partial alopecia (edge) and a sample of the normal skin