Approach to alopecia Flashcards

1
Q

What is the definition of alopecia?

A

A lack of hair in normally hairy areas

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2
Q

What are the two pathogenesis of alopecia?

A
  1. Failure of follicel to grow hair
  2. Loss of existing hair
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3
Q

What are two examples of ‘lack of follicles’ ?

A
  • Alopecia Hypotrichosis
  • Canine Ectodermal Dysplasia
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4
Q

What is follicle dysplasia?

A

A group of often ill-defined alopecia disorders that are frequently linke dto coat colouring

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5
Q

What is structural follicular dysplasia?

A

Disorder of follicle development that affects young to middle aged dogs
Weak hairs then break easily
Usua

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6
Q

What is colour dilution alopecia?

A

Blue/ Fawn coated breeds
Melanocyte dysfunction in the follicle
Coat is normal at birth -> starts losing hair at 6 months to 2 years

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7
Q

What is black hair follicular dysplasia?

A

Rare
Occurs in black haired areas
Associated with defective pigmentation
Puppies are normal at birth
Similiar to colour dilution

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8
Q

What is cyclical follicular dysplasia?

A

Often occurs in autumn or spring
2-4 years of age
Hair can regrow

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9
Q

What may assist with cyclical follicular dysplasia?

A

Melatonin administration
Prophylactic use may also help

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10
Q

What is atrophic follicular patterns baldness?

A

characterised by the miniaturisation of follicles
* associated with short-coated breeds
* different patterns= ears, ventral abdomen and chest, thighs
* Often starts in late puberty
* Dachsshund, Chihuahua, Sight hounds
* May progress to complete alopecia (skin becomes hyperpigmented)

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11
Q

What is idiopathic bald thigh syndrome of greyhounds?

A

Caused by structural hair shaft defects
Associated with downregulation of genes
Usually in young adults
Complex mode of inheritance

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12
Q

How does an endocrine disease cause an abnormal follicle cycle?

A
  • Several hormones are involved in the maintenance of healthy follicle and hair growth
  • Hairs arrest in telogen
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13
Q

What is alopecia X in dogs?

A
  • Hair cycle arrests
  • Primary hairs are affected first
  • Gradual hair loss over the trunk and caudal thighs
  • Spares the head and forelimbs
  • Thought to be an adrenal sex hormone imbalance
  • Breed predisposition = poodles and pomeranians (2-5 years of age)
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14
Q

How would you treat alopecia in dogs?

A

Thyroxine, Trilostane, Melatonin, Castration, Deslorelin

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15
Q

Give a couple of examples of systemic diseases that cause an abnormal follicle cycle?

A
  1. Hepatic disease
  2. End Stage Renal Disease
  3. Pancreatic Disease
  4. Neoplasia
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16
Q

What two drug therapies can cause an abnormal follicle cycle?

A
  • Cytotoxic drugs
  • Steroids
17
Q

What is telogen effluvium?

A

Stressful event causes abrupt cessation of hair growth in the anagen phase
Hair follicles then become synchronised in the telogen phase
2-3 months after the event the telogen hairs shed

18
Q

What 4 things can cause damage to follicles?

A
  • Infection
  • Immune Mediated Disease
  • Neoplasia
  • Trauma
  • Tail gland hyperplasia
19
Q

What is sebaceous adenitis?

A

Autoimmune response against sebaceous glands in hair follicles
Usually in young to middle aged dogs
Variety of treatments= VIT A, EFA’s cyclosporine

20
Q

What is the drug reaction to immune mediated disease?

A
  • Topical reaction or injection site reaction
  • Hair loss may be immediated or delayed and may not regrow
21
Q

What is alopecia areata?

A
  • rare
  • multifocal patchy hair loss
  • affects many animals
  • autoantibodies directed against hair follicle proteins
  • Hair regrowth is often spontaneous
22
Q

What is feline psychogenic alopecia?

A
  • Hair loss and/or skin damage resulting from displacement grooming in reaction to stressors
  • Diagnosis of exclusion = when all medical conditions are ruled out
  • Address the associated stressors
  • Use desensitisation and counterconditioning techniques to deal with any underlying fears
  • Treatment is only effectivce with behavioural modification
23
Q

What breeds are most likely to be affected by structural follicular dysplasia?

A
  • Irish water spaniel
  • Portugese water dog
  • Doberman
  • Weirmaner
24
Q

What dogs are genetically predisposed to cyclical follicular dysplasia?

A
  • Boxers
  • Bulldogs
  • Airedales
  • Schnauzers
25
Q

When does atrophic follicular pattern baldness usually start

A
  • Often starts in late puberty
  • may progress to complete alopecia
  • skin may become hyperpigmented over time
26
Q

What causes hyperestrogenism?

abnormal follicle cycle

A

Male dogs with Sertoli cell tumours
* castrate
* Bitches with cystic ovaries
* spay

27
Q

What causes pituitary dwarfism?

A

Inadequate secretion of growth hormone
* Retardation of growth and progressive hair loss
* Genetic predisposition in GSD’s
* Treatment: growth hormone £££££
* Progestogens and thyroxine, but side effects

28
Q

What causes alopecia in dogs?

A

Hair cycle arrest
* Primary hairs affected first – soft, downy secondary hairs remain
* Gradual hair loss over trunk and caudal thighs
* Sparing head and forelimbs
* Thought to be adrenal sex hormone imbalance
* Similarity with hyperoestrogenism
* Breed predisposition
* Poodle; Pomeranian (and arctic breeds)
* 2-5 years of age
* Treatment: thyroxine, trilostane, melatonin, castration, deslorelin – side effects* Aesthetic concern only

29
Q

What kind of systemic disease may interrupt the hair growth cycle?

A
  • Hepatic disease
  • End-Stage Renal Disease
  • Pancreatic disease
  • Neoplasias
30
Q

Name a bacterial infection that causes follicle damage?

A

Dermatphilus congolensis

31
Q

What is sebaceous adenitis?

A

Autoimmune response against sebaceous glands in hair follicles
* Genetic predisposition; mostly seen in dogs; rarely in other mammals* Young to middle aged dogs
* Two expressions in dogs
* Long coated breeds – poodle, Akita, Samoyed – lesions ears, back and flanks* Short coated breeds – Viszla – facial lesions and generalised moth-eaten lesions* Variety of treatments: Vit A; EFAs; cyclosporine
* Secondary infections common – bacterial/fungal

32
Q

What is alopecia areata?

A

Multifocal patchy hair loss
* Affects many animals
* In dogs often symmetrical, affecting face, head and legs
* Autoantibodies directed against hair follicle proteins
* Hair regrowth is often spontaneous (one paper cited remission in 60% of
cases) – regrowth may be lighter (non-pigmented)
* Resistant cases usually respond to corticosteroids or cyclosporin

33
Q

What is feline psychogenic alopecia?

A

Hair loss and/or skin damage resulting from displacement
grooming in reaction to stressors which may be emotional or
environmental.
* Diagnosis of exclusion –made when all medical differentials ruled out
* Since psychogenic alopecia is a multifactorial condition, treatment will need to be
tailor made for each case
* Address associated stressors
* Increase stability of the emotional and physical environment of the cat
* Use desensitization and counterconditioning techniques to deal with any
underlying fears or phobias relating to specific stimuli.
* In severe cases psychopharmacology may be needed for example with tricyclic
antidepressants or serotonin reuptake inhibitors (SSRIs).
* Treatment will only be effective in combination with behavioural modification