Alopecia

Question 1

What are the three stages of the hair growth cycle and what occurs in each of them?

Answer 1

Anagen = active growth
Catagen = involution of the hair shaft
Telogen = no growth

Question 2

Where are the keratinocytes that form hair shafts?

Answer 2

Situated at the matrix of the hair bulb

Question 3

What are the two processes that allow for hair growth?

Answer 3

Epidermopoiesis and keratogenesis

Question 4

Describe the three main pathogenic mechanisms that result in alopecia.

Answer 4

Destruction or distortion of normally growing hair follicles and hair shafts.
Abnormalities of the hair cycle causing atrophy of hari follicles and regression of hair growth.
Abnormalities of hair follicle and hair shaft development causing structural defects, hair fragility and failure of normal growth of hair.

Question 5

List three causes of the destruction or distortion of normally growing hair follicles and hair shafts.

Answer 5

Traumatic alopecia, folliculitis and inflammatory alopecia

Question 6

What would cause abnormalities of the hair cycle causing atrophy of hari follicles and regression of hair growth?

Answer 6

Endocrinopathies

Question 7

What must occur initially for dermatophytosis?

Answer 7

Adherence between keratinocytes and arthrospores.

Question 8

What is the incubation period of dermatophytes?

Answer 8

1 to 3 weeks

Question 9

List three dermatophytes that are associated with infections?

Answer 9

Microsporum canis
Trichophyton
Microsporum gypseum

Question 10

List three clinical signs of dermatophytes.

Answer 10

Alopecia
Scale
Folliculitis and furunculosis

Question 11

Which media would you use for fungal culture of dermatophytes?

Answer 11

Sabouraud’s media

Question 12

Describe how you would perform Wood’s Lamp technique for diagnosis of dermatophytes.

Answer 12

Lamp should be warmed up for five minutes.
Animal should be examined in a darkened room for several minutes to allow lesions to fluoresce.

Question 13

What is Wood’s lamp technique useful for?

Answer 13

Useful for M. canis isolates ONLY

Question 14

How far may infection spread from obvious lesions of dermatophytes?

Answer 14

Up to 6cm away

Question 15

Which shampoo and which dip/rinse can you use as topical therapy for dermatophyte infection? How often should you use them?

Answer 15

Shampoo - malaseb
Dip/rinse - enilconazole (imaverol)
Twice weekly and left of for 10 minutes

Question 16

List the two medications that you can use for systemic therapy for dermatophytes.

Answer 16

Itraconazole (7 days x 3 with 7 days between each)
Ketoconazole

Question 17

Which dermatophyte usually causes equine dermatophytosis?

Answer 17

Trichophyton spp.

Question 18

Whivh horses are usually affected by equine dermatophytosis?

Answer 18

Young horses

Question 19

What topical therapy can you use for equine dermatophytosis?

Answer 19

Miconazole shampoo
Enilconazole

Question 20

List three methods of diagnosing demodex

Answer 20

Deep skin scrapings
Hair plucks
Skin biopsy

Question 21

List three factors that would consititute generalised demodicosis

Answer 21

More than five lesions
One major body region affected
Two or more feet

Question 22

How would you treat demodex?

Answer 22

Moxidectin
Isoxazolines - afoxolaner, fluralaner, lotilaner, sarolaner

Question 23

How would you treat bacterial pyoderma associated with demodex?

Answer 23

Bathe with chlorhexidine-based shampoo three times a week.
Oral cefalexin 30 mg/kg bid for 4-12 weeks if there is no response to topical therapy or if deep infection is present

Question 24

Which breed of dog has congenital hair follicle dysplasia?

Answer 24

Chinese crested dogs

Question 25

How would you diagnose hair follicle dysplasia?

Answer 25

Histopathology
Rule out endocrine disease