Localized or Generalized Alopecia

Question 1

definition of alopecia

Answer 1

loss of hair from areas of the body where it is normally present

Question 2

basic causes of alopecia

Answer 2

decrease in hair numbers, hair miniaturization, or hair breakage

Question 3

diagnosis of cause of alopecia

Answer 3

skin scraping, cytology, fungal culture, trichography, skin biopsy

Question 4

what is trichography useful for

Answer 4

determining if hair loss is due to self-trauma and detecting follicular dysplasia

Question 5

what further tests should be done with generalized alopecia

Answer 5

minimum data base (bloodwor and U/A) and endocrine testing

Question 6

differentials for alopecia

Answer 6

folliculitis
vaccine-associated ischemic dermatopathy
familial canine dermatomyositis
hyperadrenocorticism
hypothyroidism
alopecia X
cyclic flank alopecia
pattern baldness
color dilution alopecia
sertoli cell tumor
anagen defluxion
telogen defluxion
feline symmetrical alopecia

Question 7

3 most common causes of localized alopecia

Answer 7

bacterial folliculitis (dog)
demodicosis (dog)
dermatophytosis (cat)

Question 8

what is vaccine associated ischemic dermatopathy

Answer 8

alopecia over a vaccine site

Question 9

cause of vaccine associated ischemic dermatopathy

Answer 9

caused by focal cutaneous vasculitis which leads to ischemic injury of skin

Question 10

when and in what breeds does vaccine associated ischemic dermatopathy occur in

Answer 10

few months after vaccine

fluffy white breeds – mini poodles and bichon frises

Question 11

diagnosis of vaccine associated ischemic dermatopathy

Answer 11

clinical signs, history of vaccine and FNA +/- skin biopsy

rule out demodicosis

Question 12

treatment of vaccine associated ischemic dermatopathy

Answer 12

pentoxifylline – anti-inflammatory methylxanthine to improve blood flow through damaged vessels

Question 13

what is familial canine dermatomyositis

Answer 13

hereditary, idiopathic inflammatory condition of the skin and sometimes muscles

Question 14

what breed does familial canine dermatomyositis occur commonly in

Answer 14

shetland sheep dogs and collies – autosomal dominant with variable gene expressivity

Question 15

when do alopecic lesions of familial canine dermatomyositis occur

Answer 15

most commonly before 6 months and can progress up to a year

Question 16

lesions of familial canine dermatomyositis

Answer 16

alopecia, erythema, scaling and mild crusting;
+/- mild pruritus
can have marked atrophy (thin skin with no visible hair follicles)

Question 17

diagnosis of familial canine dermatomyositis

Answer 17

clinical signs and skin biopsy;

also do a skin scraping to rule out demodicosis

Question 18

treatment of familial canine dermatomyositis

Answer 18

pentoxifylline, vitamin E

possibly cyclosporine or topical tacrolimus

Question 19

how does hyperadrenocorticism cause alopecia

Answer 19

hypercortisolism suppresses hair growth leading to telogenization of hairs

Question 20

characteristics seen in the skin with hyperadrenocorticism

Answer 20

thin, hypotonic skin
symmetrical alopecia
easy bruising
poor wound healing
seborrhea sicca
increased susceptibility to bacterial infection and demodicosis
calcinosis cutis
comedones
coat color lightening

Question 21

3 characteristic findings with hyperadrenocorticism

Answer 21

thin skin, comedones and calcinosis cutis

Question 22

systemic signs of hyperadrenocorticism

Answer 22

PU/PD/PP, panting, muscle wasting, pot-belly appearance

Question 23

confirmation of hyperadrenocorticism can be made with what test

Answer 23

ACTH stimulation test

Question 24

what does hypothyroidism cause regarding the skin

Answer 24

epidermal atrophy and abnormal keratinization

Question 25

lesions of hypothyroidism

Answer 25

scaly, dry and hyperpigmented skin skin can be thicker than normal failure of hair to grow because thyroid hormone is necessary to initiate anagen

Question 26

when does pruritus occur with hypothyroidism

Answer 26

when a secondary bacterial infection is present

Question 27

common location for alopecia with hypothyroidism

Answer 27

tail and bridge of nose

Question 28

diagnosis of hypothyroidism

Answer 28

low free T4 levels + clinical signs

Question 29

classic hypothyroid dogs show what levels of T4, free T4 and TSH

Answer 29

low T4 and free T4 | high TSH

Question 30

which breeds are predisposed to alopecia X

Answer 30

pomeranians, siberian huskies, samoyeds, malamutes, mini poodles

Question 31

when do clinical signs of alopecia X start to occur

Answer 31

before 3 years of age

Question 32

clinical signs of alopecia X

Answer 32

dull, dry hair coat with loss of primary hairs; | alopecia affecting the trunk, caudal thighs, neck and tail

Question 33

treatment of alopecia X

Answer 33

S/N intact dogs; oral melatonin; other treatments are controversial because of adverse effects to treat a cosmetic disease

Question 34

clinical signs of cyclic flank alopecia (dog)

Answer 34

bilaterally symmetrical hair loss and hyperpigmentation in the flanks that resolves without treatment but may recur in the future

Question 35

which breeds are affected by cyclic flank alopecia

Answer 35

bull dogs, boxers, airedale terriers

Question 36

diagnosis of cyclic flank alopecia

Answer 36

skin biopsy showing dysplastic, keratin filled follicles

Question 37

treatment of cyclic flank alopecia

Answer 37

no treatment required; | can use oral melatonin to speed hair regrowth and prevent in future

Question 38

which colors does color dilution alopecia occur in

Answer 38

blue or fawn coat colors

Question 39

which breed is the poster child for color dilution alopecia

Answer 39

doberman

Question 40

what is a characteristic finding regarding the hairs in color dilution alopecia

Answer 40

brittleness and breakage of affected hairs by 6 months of age

Question 41

cause of color dilution alopecia

Answer 41

abnormal melanin deposition in hair shafts and skin --> large irregular macromelanosomes disrupt the integrity of the hair shaft

Question 42

true or false: dogs with color dilution alopecia are prone to secondary bacterial infections

Answer 42

true

Question 43

diagnosis of color dilution alopecia

Answer 43

rule out other causes of alopecia by skin scraping and biopsy trichogram should show characteristic clumping of melanin

Question 44

treatment of color dilution alopecia

Answer 44

avoid mechanical trauma and treat secondary infections; | can try melatonin but prognosis for hair recovery is poor

Question 45

what is feline symmetrical alopecia

Answer 45

a cutaneous reaction pattern

Question 46

cause of feline symmetrical alopecia

Answer 46

commonly overgrooming --> may be due to pruritus or psychogenic other possible underlying cause: hyperthyroidism of FLUTD

Question 47

diagnosis of feline symmetrical alopecia

Answer 47

trichograms show ends of hair are broken; | biopsy will show growing anagen hairs

Question 48

differentials for feline symmetrical alopecia

Answer 48

flea bite hypersensitivity, atopic dermatitis, adverse food reaction, dermatophytosis, cheyletiella; less commonly could be truly psychogenic

Question 49

what is anagen defluxion

Answer 49

when an insult, such as severe disease or antimitotic drug, causes hair shafts to break off suddenly

Question 50

when does hair loss occur with anagen defluxion

Answer 50

within days of insult

Question 51

what is telogen defluxion

Answer 51

seen 1-3 months after insult and results from hair follicles entering the telogen phase in synchrony due to stressful incident or drugs