Lecture 7 2/10/25

Question 1

What can cause loss of hair?

Answer 1

-traumatic removal/scratching out
-spontaneous falling out
-lack of new hair growth

Question 2

Which inflammatory conditions can cause hair to fall out?

Answer 2

-pyoderma
-demodicosis
-dermatophytosis

Question 3

What is the distribution of non-inflammatory alopecias?

Answer 3

-more diffuse
-often symmetrical
-spares the extremities

Question 4

What are the two broad categories of non-inflammatory alopecia causes?

Answer 4

-diseases associated with abnormal hair growth
-hair cycle abnormalities

Question 5

What are the characteristics of telogen hairs?

Answer 5

-not a pathologic state
-do not have to shed
-can be difficult to pull out

Question 6

Which breed has an anagen-dominant hair cycle?

Answer 6

poodles and poodle mixes

Question 7

What are the characteristics of follicular dystrophies/dysplasias?

Answer 7

-abnormality of the development of the hair
-becomes apparent during anagen
-hairs are abnormal, fragile, and malformed
-trule follicular dysplasias are rare

Question 8

Which breed has a true follicular dysplasia/ectodermal defect?

Answer 8

chinese crested

Question 9

What are the characteristics of congenital hypotrichosis?

Answer 9

-not well characterized
-can be born without normal pelage
-can be born with normal pelage and have hair loss within first 6 months of life
-non-inflammatory

Question 10

What is the mechanism behind color dilution alopecia/black hair follicular dysplasia?

Answer 10

defective melanization due to defects in melanosome migration/transfer

Question 11

What are the clinical signs of color dilution alopecia/black hair follicular dysplasia?

Answer 11

-alopecia that is color-restricted
-seborrhea
-pyoderma

Question 12

How is color dilution alopecia diagnosed?

Answer 12

-trichogram; can see the melanosomes clumped and bulging
-histopath; can see melanin clumping within shaft and periadnexally

Question 13

What is the treatment for color dilution alopecia?

Answer 13

symptomatic treatment of the seborrhea and pyoderma

Question 14

What are the clinical signs of hair cycle issues?

Answer 14

-bilateral symmetrical diffuse alopecia
-dull, dry, brittle hair
-hair fails to grow back after clipping
-pigmentary changes/bleached hairs
-seborrhea/comedones
-secondary infections
-nonpruritic

Question 15

What are the endocrine causes of alopecia/hair loss?

Answer 15

-hypothyroidism
-cushing’s
-hyperestrogenism

Question 16

What are the dermatologic signs of hypothyroidism?

Answer 16

-alopecia, especially in areas of wear
-failure to shed
-failure to grow past clipping
-bleaching of hairs
-myxedema
-recurrent infections

Question 17

What are the dermatologic signs of cushing’s?

Answer 17

-symmetrical alopecia
-thinned hair coat/hypotrichosis
-atrophy of the skin
-comedones
-milia
-recurrent pyoderma
-hyperpigmentation
-poor wound healing
-bruising
-demodicosis
-calcinosis cutis

Question 18

What are the possible sex hormone dermatoses?

Answer 18

-hyperestrogenism
-hyperandrogenism

Question 19

What are the possible causes of hyperestrogenism?

Answer 19

-cystic ovaries
-testicular tumors
-iatrogenic

Question 20

Why does elevated estrogen lead to hair loss?

Answer 20

estrogen inhibits anagen initiation

Question 21

What are the clinical features of hyperestrogenism?

Answer 21

-bilaterally symmetric alopecia
-comedones
-secondary seborrhea
-hyperpigmentation
-enlarged nipples and vulva (females)
-irregular heat cycles (females)
-linear preputial dermatosis (males)
-macular melanosis (males)
-abnormal testicles (males)

Question 22

When is hyperandrogenism an issue?

Answer 22

animals that have androgen-responsive hair follicles; example is lions

Question 23

What is the pathogenesis behind hyperandrogenism?

Answer 23

-testicular tumors
-adrenal tumors

Question 24

What are the clinical features of hyperandrogenism?

Answer 24

-intact males
-hyperplasia of circumanal glands
-tail gland hyperplasia
-seborrhea oleosa
-rarely alopecia

Question 25

What are the characteristics of alopecia X?

Answer 25

-adrenal hyperplasia-like syndrome -response to growth hormones -castration responsive -biopsy responsive -pseudo-cushing's

Question 26

Which breeds develop alopecia X?

Answer 26

plush-coated breeds

Question 27

What is the typical presentation of alopecia X?

Answer 27

-adult dogs 1 to 10 years of age -males equal to females -loss of truncal hair -hyperpigmentation -not systemically ill -not cushingoid or hypothyroid

Question 28

What is the pathomechanism of alopecia X?

Answer 28

not known, but thought that patient has a failure to initiate or maintain anagen

Question 29

How is alopecia X diagnosed?

Answer 29

-rule out cushing's and hypothyroidism -biopsy to confirm non-inflammatory alopecia and rule out sebaceous adenitis

Question 30

What are the treatment options for alopecia X?

Answer 30

-castration -growth hormones -testosterone -mitotane -melatonin -trilostane -medroxyprogesterone

Question 31

What is the long term prognosis for alopecia X?

Answer 31

-poor prognosis for maintaining hair growth; often lose hair again on subsequent hair cycle -treatment should be stopped once hair grows back to give treatment best chance of working again if hair is lost again

Question 31

Which conditions are considered patterned alopecia?

Answer 31

-tardive hypotrichosis -pinnal alopecia of dachshunds -ventral and caudal alopecia of dachshunds and bostons -pattern alopecia of portuguese water dogs, irish water spaniels, and american water spaniels -caudal thigh alopecia of greyhounds

Question 32

What are the characteristics of cyclic flank alopecia?

Answer 32

-seasonal truncal alopecia -hair loss usually occurs in winter -more common in dogs in northern regions -may not happen every year

Question 33

Which breeds are predisposed to cyclic flank alopecia?

Answer 33

-airedale -boxer -english bulldog -french bulldog -other short-coated breeds

Question 34

What is the clinical presentation of cyclic flank alopecia?

Answer 34

-age of onset between 1.5 and 4.5 years old -usually symmetrical -often hyperpigmented

Question 35

How is cyclic flank alopecia diagnosed and treated?

Answer 35

-diagnosed by ruling out endocrinopathies and doing a biopsy -treatment via melatonin and potentially low-level laser

Question 36

What are the characteristics of post-clipping alopecia?

Answer 36

-failure to regrow hair following close clipping -seen following surgical procedures or epidurals -hair usually grows back within 1 year -can be seen in plush-coated breeds when clipped at wrong time in hair cycle

Question 37

How is post-clipping alopecia diagnosed?

Answer 37

-rule out endocrinopathies -biopsy possible but not indicated

Question 38

What are the treatments for post-clipping alopecia?

Answer 38

-time -melatonin

Question 39

What is telogen defluxion?

Answer 39

hair loss 1 to 3 months after a stressful incident or illness

Question 40

What are the characteristics of excessive shedding?

Answer 40

-normal shed cycles occur in spring and fall -if shedding is normal, cannot epilate until bald -hyper dogs may shed more -should check for endocrinopathies

Question 41

What are the treatments for excessive shedding?

Answer 41

-regular grooming with antiseborrheic shampoo -diet changes/adding fatty acids -adjusting light and/or temperature exposure