Module 7: Alopecia (Weeks 8 & 9) Flashcards
1
Q
List the causes of acquired canine alopecia:
A
- Pattern Baldness
- Color dilution Alopecia
- Black Hair Follicular Dysplasia
- Seasonal Flank Alopecia
2
Q
Hair Follicles
Most omnivores and herbivores have simple follicles which means …
A
each infundibulum contains 1 hair shaft
3
Q
Hair Follicles
Carnivores (dogs & cats) and rabbits, have compound follicles which means …
A
infundibulum contains multiple hair shafts
- Some hair follicles in the compound follicle have a large diameter – Primary or guard hairs – but the majority have a small diameter – secondary or undercoated hairs
4
Q
Hair Follicles
Human & Sheep depending on body location have …
A
simple or compound follicles
- Human: head mostly compound, body simple
5
Q
Hair Cycle
Hair follicles show intermittent activity:
- Is the period of active growth => _____________
- Is the transitional phase => _____________
- Is the resting phase of the hair cycle => _____________
A
- Anagen
- Catagen
- Telogen
6
Q
Factors Influencing Hair Cycle
The Relative duration of the cycle varies with:
A
- Age
- Region of the body
- Breed
- Sex
(Can be modified by a variety of extrinsic and intrinsic factors)
7
Q
Factors Influencing Hair Cycle:
- Photoperiod
- Ambient temperature
- Hormones (thyroidal, gonadal, adrenal, pituitary and pineal)
- General state of health
A
Extrinsic Factors
8
Q
Factors Influencing Hair Cycle:
- Growth factors and cytokines
A
Intrinsic factors
9
Q
Definition:
Is a partial or complete lack of hair in areas where it is normally present
A
Alopecia
Classification:
- Congenital
- Acquired
- Auto-inflicted
- Infectious
- Inflammatory Reactions
- Miscellaneous
- Follicular dysplasia
- Endocrinopathies
10
Q
Clinical Approach: Alopecia
History and general physical examination directed to detect abnormalities in other organs
List Clinical Signs:
A
- PU/PD
- Pendulous abdomen
- Testicular asymmetry or cryptorchidism
- Vulvar enlargement
- Changes in activity level
- Weight gain
11
Q
Clinical Approach
(T/F) If pruritus is present, the cause of pruritus should be investigated first
A
True
- If absent: Pattern of hair loss, Presence of inflammation, Presence of lesions
- Skin scraping, skin cytology, dermatophyte culture
12
Q
Clinical Approach: Breeds
Alopecia X
A
Pomeranians
13
Q
Clinical Approach: Breeds
Pattern baldness
A
- Dachsunds
- Boston Terriers
- Chihuahuas
- Whippets
- Manchester Terriers
- Greyhounds
- Italian Greyhounds
14
Q
Clinical Approach
List some of the causes for failure to regrow hair after clipping:
A
- Hypothyroidism
- Hyperadrenocorticism
- Alopecia X
- Post clipping alopecia
15
Q
List Non-Inflammatory Alopecia:
A
- Pattern Baldness
- Miniaturization of the hair follicle
- Follicular Dysplasias
- Color Dilution Alopecia
- Black hair follicular dysplasia
- Seasonal flank Alopecia
- Endocrine dermatopathies
- Sertoli cell Tumors
- Hypothyroidism
- Cushing’s disease
- Hair cycle arrest (Alopecia X)
16
Q
Pattern Baldness:
What are the Four Syndromes?
A
- Most Common: alopecia pinnae, ventral neck, ventrum, caudomedial thighs
(alopecia remains restricted to these areas) - Pinnal alopecia of Dachshunds: Complete pinnal alopecia by 8-9 year old
-
Caudal thigh alopecia of greyhounds
- Bald thigh syndrome in sighthounds
- Possible causes have been proposed
- environmental, trauma, stress -
American Water Spaniels - most likely a follicular dysplasia (50% of cases)
- Alopecia neck, caudal thighs and trunk
17
Q
- Dachshunds
- Boston Terriers
- Chihuahuas
- Whippets
- Manchester terriers
- Greyhounds
- Italian Greyhounds
These are the most common breeds with …
A
Pattern Baldness
18
Q
History - Early onset, breed predisposition
Rule out:
- Hair follicle dysplasia
- Sex hormone dermatoses
- Hypothyroidism
- Hyperadrenocorticism
- Alopecia areata (autoimmune)
Histopathologic examination - Biopsy samples from affected and normal skin
A
Pattern Baldness
19
Q
Pattern Baldness: Treatment
A
- Oral melatonin: good response in approximately 50% of the cases
- Doses: 3-6 mg PO q 8-12 h
- Give for 2-3 months before evaluating response - Low level laser or phototherapy
20
Q
- “Color mutant alopecia,” “Blue dog disease”
- Inherited autosomal recessive disorder – abnormalities in melanin transfer and storage
A
Color Dilution Alopecia
- Dogs with color-diluted coats (blue or fawn) are affected e.g. Dobermans, Italian greyhounds, chihuahuas, labradors
21
Q
- Hypotrichosis to alopecia affecting diluted areas
- Clinical signs start between 6 months and 3 years
- The rate of hair loss is variable
- Prone to develop bacterial folliculitis
These are clinical signs for …
A
Color Dilution Alopecia
22
Q
- Breed and coat color are suggestive
- Trichogram: shows hairs with large melanin clumps, causing distortion and fracture of the hair shaft
- Histopathologic examination to confirm diagnosis
These are the …
A
Diagnosis for Color Dilution Alopecia
23
Q
- Seen in bi- or tricolored breeds and solid-colored (black) breeds
- Coat changes are noted as early as 4 weeks
- Progressive hair loss until all black hairs are lost
A
Black Hair Follicular Dysplasia
24
Q
- Only the black coat affected is very suggestive
- Rule out demodicosis and dermatophytosis
- do skin scrapes - Histopathology
- Melanin clumping
These are the …
A
Diagnosis for Black Hair Follicular Dysplasia
25
Black Hair Follicular Dysplasia: Treatment
- *No* effective treatment
- Treat secondary infections if present
- Do not use harsh shampoos, be gentle when grooming
26
- Episodes of recurrent truncal hair loss
- High incidence in some breeds suggests genetic influence
- The seasonal nature and annual recurrence suggest the influence of photoperiod
- Onset of alopecia occurs mostly between late autumn and early spring
Seasonal Flank Alopecia
27
List the Breeds more commonly affected by *Seasonal Flank Alopecia*:
- Boxer
- English bulldog
- French bulldog
- Miniture schnauzer
- Airedale terrier
28
- Ruling out another clinical differential diagnosis
- *Hypo*thyroidism
- Demodicosis
- Sex hormone imbalance
- Alopecia X
- *Histopathology:* multiple biopsy samples from
the affected area(s)
These are the ...
Diagnosis for Seasonal Flank Alopecia
29
How would you manage Seasonal Flank Alopecia?
- Difficult to evaluate response to treatment due to spontaneous hair regrowth
- *Oral Melatonin*: 3-6 mg q 8 to 12 h for 1-2 months. Start before or shortly after the onset of alopecia
- Cosmetic problem
- Low level laser or phototherapy
30
What can help to confirm diagnosis of Seasonal Flank Alopecia?
- *Biopsy*: mutiple samples from the affected and non-affected areas
- *Histopathology*: dystrophic, *atrophic and keartin-filled hair follicles with finger-like projections into the dermis*
31
Alopecia X
Alopecia X
32
Term:
Has been recently adopted because the nature of this condition is currently unknown
Alopecia X
- "adrenal sex hormone imbalance"
- Hormonal imbalance or change in receptor sensitivity at the hair follicle level are suspected
33
List the breeds mostly associated with Alopecia X:
Pomeranians, Keeshond, Chow Chows, Samoyed, miniture poodles
34
What is the typical signalment for Alopecia x?
- M/F, intact or neutered
- Middle age to older
- Specific to some breeds
35
List the clinical signs foe Alopecia X:
- Bilaterally symmetric alopecia originating in frictional areas
- Primary hairs are lost first followed by a variable loss of secondary hairs-- "puppy-like coat"
- Rump, perineum, caudal thighs, neck, tail
- end-stage disease may result in total alopecia of the trunk, neck and proximal legs
- Head and distal legs are usually spared
36
How do you rule out endocrinopathies?
- ACTH stimulation test
37
Histopathology:
- Areas of most advanced hair loss
38
(T/F) Melatonin can be used for Alopecia X
True, one study showed hair regrow in 14/23 pomeranians with Alopecia X after 4 months
39
How long will it take to see improvements using Melatonin?
3 months
40
Alopecia X - Treatment:
- Blocks the excessive production of cortisol by reversibly inhibiting the action of the enzyme 3-beta hydroxysteriod dehydrogenase
Trilostane
41
(T/F) Microneedling also works as a treatment for Alopecia X
True
42
low level laser "phototherapy"
43
Alopecia - Hormonal
- Sertoli Cell Tumor
- Hypothyroidism
- Hyperadrenocortisicism
- Alopecia X
44
What does Sertoli cell tumors normally cause?
Male feminization Syndrome:
- Middle aged to older dogs
- Functional Sertolli cell tumors are most common in cryptorchid
45
List the breed predisposition to Sertoli cell tumors:
- Boxers, Shelties, Collies, Weimaraners, Cairn terrier, Pekingese
46
List the clinical signs for Sertoli cell tumors:
- Linear preputial dermatosis
- Pendulous prepuce
- Gynecomastia
- Enlarged nipples
- Prostate is often enlarged and it can be infected
47
How do we manage?
- Castartion usually curative
- Clinical response is seen within 3 months
- *Remission followed by relapse indicates functional metastases*
- *Cisplatin* can be tried for cases associates with metastases
- Dogs with *estrogen-induced bone marrow suppression* have a *poor prognosis*
48
Hypothyroidism
Hypothyroidism
49
- May develop because of a defect in any part of the hypothalamic - pituitary - thyroid axis
- Congenital - uncommon (dwarfism)
- *Acquired* - more common
- *Primary hypothyroidism* - most cases
- Secondary hypothyroidism - inadequate production of TSH from the pituitary gland < 5% of cases
Hypothyroidism
50
What is the most common endocrine disorder in dogs?
Primary Hypothyroidism
- lymphocytic thyroiditis or idiopathic atrophy
- Progressive destruction of the thyroid gland - over 1-3 years
- *75%* gland must be destroyed before clinical signs develop
51
Signalment for primary hypothyroidism:
- 7-year-old (middle age)
- Spayed females and neutered male dogs are at increased risk
- Golden retrievers, dobermans, great danes, shelties, and other breeds predisposed to hypothyroidism tend to develop the disease earlier (2-3 years)
52
List the dermatologic manifestations of hypothyroidism:
- Thinning hair coat
- *Symmetrical non-inflammatory alopecia*
- Hyperpigmentation
- Seborrhea
- abnormal keratinization
- greasy or dry
- generalized
- "rat tail"
- Secondary infections
- Myxedema (less often)
- Accumulation of glycosaminoglycans
- Failure to regrow hair after clipping
** occur in about 70% of dogs **
53
What promotes the initiation of *the anagen* phase of the hair cycle?
Thyroid Hormones
54
List the Neuromuscular abnormalities of Hypothyroidism:
- Weakness
- Facial nerve paralysis
- *Vestibular disease*
- its confused with ear infections
- Seizures may occur secondary to serve hyperlipidemia
- Megaesophagus and laryngeal paralysis have been reported but not proven
- Insulin resistance
55
What is the most severe form of hypothyroidism?
Myxedema coma
- impaired mental status
- treatment w/ intravenous I-thyroxine is recommended
56
List finds of Diagnosis-Routine lab work:
- *Hypercholesterolemia*
- 75% of cases
- Mild nonregenerative anemia
- Hyponatremia
- Elevated ALP, CK?
57
Autoantibodies to T4 or T3:
- False elevation of affected hormone
- elevation may be marked (into hyperthyroid range) or may bring T4 into the normal range
- Does *not* affect fT4d
interfere with assays for T4 or T3
58
Which are thyroid-sensitive teats?
T4 and fT4
(TSH (elevated) is *less* sensitive)
59
(T/F) A combination of low T4 or fT4 and elevated TSH is very accurate for the diagnosis of primary hypothyroidism
True
60
Treatment for hypothyroidism:
Levothyroxine
- Overdose signs: anxiety, panting, PD/PU/PP, diarrhea, pruritus
61
Hyperadrenocorticism
Hyperadrenocorticism
62
What is another endocrine disease common in dogs?
Hyperadrenocorticism
- *Excess cortisol production* by the adrenal glands
- *Iatrogenic* due to administration of glucocorticoids
63
Naturally occurring:
(T/F) Most cases of hyperadrenocorticism are due to Adrenal tumors
False, it is due to PDH (80-85%)
- There are rare reports of dogs having both
64
- Pituitary microadenoma (80-90%) less than 1 cm in diameter
- Pituitary macroadenomas
Pituitary dependent hyperadrenocorticism
65
(T/F) *Macro*adenomas are much more likely to cause neurologic signs
True
66
(T/F) Adenocarcinomas are very common
False, adenocarcinomas are *RARE*
67
- Increased ACTH production from the pituitary gland
Pituitary Adenomas
68
- Adenomas or adenocarcinomas affecting one (common) or both (rare) adrenal glands
Adrenal Tumors
69
- Thin skin and hyperkeratosis
- Atrophic hair follicles and sebaceous gland
- Fragile blood vessels (decrease collagen)
- Delayed wound healing
- Increase susceptibility to infections
- Calcinosis cutis
- calcium deposits
- firm white papules
- Treatment: Minocycline
Glucocorticoids and the skin
70
List the signalment:
- Middle-aged to older dogs (>6 years old) -> rare in young dogs
- Any breed can be affected
- 75% of dogs with PDH are < 20 kg
- No sex predilection
71
List the cutaneous signs:
- Thin
- Hypotonic
- Easy bruising
- Comedones
- skin scrape
- Poor healing
- Hyperpigmentation
72
- Free catch urine sample
- High *Sensitivity*
- Low specificity
- High negative predictive value
Urine cortisol:Creatinine ratio
73
- evaluates adrenocortical reverse
- it can differentiate spontaneously from iatrogenic Cushing's
- *Iatrogenic*
- minimal to no increase in cortisol levels
ACTH Stim test
74
- Good Screening test
- it can be abnormal with non-adrenal illness
LDDST
- high dose dexamethasone suppression test
- endogenous ACTH
- Abdominal US
- CT/MRI
75
- *Mitotane (Lysodren)*
- *Trilostane (Vetoryl)*
- *Surgery*
- Radiation
This is the treatment for ...
PDH
76
- *Trilostane*
- *Mitotane*
- *Surgery*
This is the treatment for ...
AT
77
Module 7 MiniModule 2: Dermatophytosis
Module 7 MiniModule 2: Dermatophytosis
78
(T/F) Dermatophytosis is zoonotic
True
79
(T/F) Dogs are asymptomatic carriers of dermatophytosis
False, Cats are asymptomatic
80
What is the most common dermatophyte in dogs and cats?
*Microsporum canis*
_ remember that it is in dogs AND cats
81
List th ecommon dermatophytes:
- Microsporum canis
- cats
- dogs
- microsporum gypseum
- cats
- dogs
- Microsporum persicolor
- dogs
- Trichophyton menragrophytes
- cats - uncommon
- dogs
82
Dermatophyte Infection:
What is the *infective form*?
*Arthrospore*
- formed by segmentation and fragmentation of fungal hyphae
83
Term:
Growing hair
Anagen
84
Describe the infection of dermatophytes:
Arthrospore -> Invades anagen hair *follicle* -> Folliculitis (*bacteria* can also cause folliculitis & *demodex*)
85
Stages of development:
- *Adherence* of arthroconidia to *corneocytes (skin cells)*
Stage 1
86
Stages of development:
- *Penetrate* the stratum corneum (top layer)
Stage 2
87
Stages of development:
- Dermatophyte *invasion* of keratinized structures
Stage 3
88
Term:
is an inflammatory, pus-filled sore (abscess) that sometimes oozes
Kerion = Nodular Dermatophytosis
89
What is the most common dog breed affected by dermatophytosis?
Yorkies
90
- Single or multiple erythematous, alopecic, dome-shaped, exudative nodules
- Nodules can fistulate, ulcerate and drain serous to purulent debris with tissue grains
- More superficial
Nodular Dermatophytosis = Kerion
91
Feline Clinical Signs:
- Alopecia
- Erythema
- Scale/crusting dermatitis
- Papules - "miliary dermatitis"
- Paronychia or nychodystrophy of single digit (claws affected)
- *Uncommon*
- Kerion - *Uncommon*
- Draining nodules - *P*seudomycetoma - *Persian* cats
92
- Subcutaneous nodules (one or multiple)
- reported in *P*ersian cats
- Dorsum or tail base
- Treatment:
- Systemic therapy
- +/- Surgical excision
Pseudomycetoma
93
List the *Primary Differential Diagnoses of Dermatophytosis* :
- Demodicosis
- Staphylococcal folliculitis
- Autoimmune - Pemphigus complex
- crusting pattern
94
Term:
a parasitic skin disease with medical and veterinary importance caused by the Demodex mites
Demodicosis
95
(T/F) No one test is identified as "Gold standard" for dermatophytosis
True
96
Diagnosis for dermatophytosis is confirmed by a number of tests, including:
- Wood's lamp
- only 50% of M canis *fluoresce an apple green color*
- remember that there are many different types of dermatophytes and not all fluoresce
- False positives: crusts or medications can fluoresce
- *MAIN POINT*: if hairs fluoresce, sample these for fungal culture (looking for hair shaft to light up)
- Trichogram
- Fungal culture (DTM)
- Biopsy for histopathology
- PCR
97
What is Biopsy recommended for?
- Nodular form (kerion, pseudomycetoma)
- Suspected onychomycosis
- Special stains may be needed for histopathologic diagnosis (Gomori methenamine silver or periodic acid-Schiff stains)
- Can identify the presence of spores or hyphae; *cannot identify species*
98
(T/F) PCR is going to detect viable and non-viable DNA
True
99
Fast and accurate
- > 95% sensitivity, 99% specificity
PCR
- don't use to check if treatment is working
100
(T/F) Localized treatment is recommended for dermatophytosis
False, it is *not* recommended because spores are on the entire coat, not just where the lesion is
- lime sulfur dip (2%, malodor, patient cannot lick), *miconazole/chlorhexidine shampoo*
101
(T/F) Systemic therapy for dermatophytosis can be used in patients with confirmed cases
True
- until you have 2 negative fungal cultures
102
The "-zole" are going to prevent ...
Ergosterol synthesis
- most commonly used: *Itraconazole*
103
- inhibits *squalene epoxidase*
Terbinafine
- tolerate it better
104
(T/F) You *cannot* use Ketoconazole in cats
True, they will vomit everywhere and high-risk hepatotoxicity
105
Module 7 MiniModule 3: Demodicosis
Module 7 MiniModule 3: Demodicosis
106
- Very common
- Inflammatory parasitic disease
- Characterized by the presence of larger-than-normal numbers of demodectic mites
Canine Demodicosis
- Demodex canis
- Demodex cornei
- Demodex injai
- Demodectic mange, Follicular mange, red mange
107
What is the "in-between" size mite?
Demodex canis
- Hair follicle, sebaceous glands
108
What is the smallest mite?
Demodex cornei
- Surface
109
What is the largest mite?
Demodex injai
- Hair follicles, sebaceous glands
- longest of the mites
110
- Entire life cycle on skin (18-35 days)
- Reside in hair follicles, sebaceous glands
- Feeds on cells, sebum, and epidermal debris
- Normal resident of dog's skin and ear canal
- Transmission occurs form the bitch to nursing puppies during first 2-3 days of life
Demodex canis
111
IF most dogs harbor *the mite* as part of their normal skin fauna, why do some dogs develop the generalized disease?
- Not completely understood
- Possible role of mite-specific immunoincompetence
112
List the Types of Canine Demodicosis:
- Clinical Disease
- Localized
- Generalized (squamous, greasy, pustular, pododemodicosis)
- Juvenile-onset
- Adult-onset
- Course and prognosis vastly different
- *Non-pruritic* unless secondary infection
113
Generalized Demodicosis:
- Scaly, alopecic patches
- Coalesce
- Erythema, crusting, follicular plugging, comedones
- Hyperpigmentation
Squamous
114
Generalized Demodicosis:
- +/- alopecia
- Terriers
- *D. injai*
- Greasy skin may persist after resolution of demodex
Dorsal greasy skin
115
Generalized Demodicosis:
- Very severe form (most)
- May be life-threatening
- Deep *Gram-negative* infection
- Alopecia, papules, pustules
- Furuncles, draining tracts, cellulitis, edema, ulcers, erosions, nodules
- Depressed, lethargic, febrile, septicemia
- Lymphadenopathy
Pustular
116
Generalized Demodicosis:
- Concurrent with other lesions
- Only manifestation
- Difficult to treat
Pododemodicosis
117
- Concurrent disease
- *Glucocorticoid administration*
- Hyperadrenocorticism
- Chemotherapy Rx
- Hypothyroidism
- Neoplasia
- Diagnose and treat (if possible)
- Idiopathic
- Less likely to cure
Adult-onset
118
- *Rare*
- Demodex cati: long, slender follicular mite, morphologically comparable to Demodex canis (180-210 microns long)
- Demodex gatoi: short, with broad, blunted abdomen. Dwells superficially in the stratum corneum (80-90 microns long)
- Demodex felis: (113-175 microns long) medium
Feline Demodicosis
119
List the clinical signs for D. gatoi:
- *Pruritic*, however, may be asymptomatic
- *Contagious*
- Any age
- Alopecia, scaling, crusted lesions
- Erythema, hyperpigmentation, stubby hairs
- Ventral alopecia
120
List the clinical signs for D. felis:
- +/- Pruritus
- Cats lose large clumps of hair, hairs easily epilating - smooth shiny non-inflammatory areas of alopecia
- Non-blanching erythema
- Most had URI - but were in shelter
121
What is the best test for diagnosis of Demodex canis?
Deep skin scraping
- negative rules out
122
Canine Demodicosis:
In addition to *diet, heartworm test, fecal floatation* (juvenile-onset generalized demodicosis) what else do you want to do to diagnose Adult-onset generalized demodicosis?
- CBC
- Biochemical profile
- Urinalysis
- Thyroid test
123
What is the *ONLY* FDA approved product to treat demodicosis?
Amitraz: *Mitaban*
- Broad-spectrum miticide
- Side effects
- Alpha-adrenergic agonist
- Antidote
- rinse dog
- Yohimbine IV
124
What is an FDA product NOT approved for the treatment of demodicosis?
Ivermectin
- Toxicity
- Antidote IV lipid emulsion
- Don't use in hearing breeds
- P-glycoprotein
- *test for mutation*
125
- FDA product NOT approved for Demodex treatment
- Heartworm negative
- Expensive
Milbemycin Oxime
126
- Moxidectin + imidacloprid
- Juvenile dogs with mild disease
- Weekly administration
Advantage Multi, Bayer
127
(T/F) 90% of cases of localized demodicosis will resolve on their own, so no treatment is necessary
True
128
- This is a superficial-dwelling mite
- This mite can cause pruritus
- This mite is contagious to other cats
Demodex gatoi (short)
129
You have a client with a dog with AD that also has demodicosis. What treatment is safe to use for the dog's pruritus?
Cytopoint
