Approach to alopecia

Question 1

What is the definition of alopecia?

Answer 1

A lack of hair in normally hairy areas

Question 2

What are the two pathogenesis of alopecia?

Answer 2

1. Failure of follicel to grow hair
2. Loss of existing hair

Question 3

What are two examples of ‘lack of follicles’ ?

Answer 3

• Alopecia Hypotrichosis
• Canine Ectodermal Dysplasia

Question 4

What is follicle dysplasia?

Answer 4

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

Question 5

What is structural follicular dysplasia?

Answer 5

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

Question 6

What is colour dilution alopecia?

Answer 6

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

Question 7

What is black hair follicular dysplasia?

Answer 7

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

Question 8

What is cyclical follicular dysplasia?

Answer 8

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

Question 9

What may assist with cyclical follicular dysplasia?

Answer 9

Melatonin administration
Prophylactic use may also help

Question 10

What is atrophic follicular patterns baldness?

Answer 10

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)

Question 11

What is idiopathic bald thigh syndrome of greyhounds?

Answer 11

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

Question 12

How does an endocrine disease cause an abnormal follicle cycle?

Answer 12

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

Question 13

What is alopecia X in dogs?

Answer 13

• 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)

Question 14

How would you treat alopecia in dogs?

Answer 14

Thyroxine, Trilostane, Melatonin, Castration, Deslorelin

Question 15

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

Answer 15

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

Question 16

What two drug therapies can cause an abnormal follicle cycle?

Answer 16

• Cytotoxic drugs
• Steroids

Question 17

What is telogen effluvium?

Answer 17

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

Question 18

What 4 things can cause damage to follicles?

Answer 18

• Infection
• Immune Mediated Disease
• Neoplasia
• Trauma
• Tail gland hyperplasia

Question 19

What is sebaceous adenitis?

Answer 19

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

Question 20

What is the drug reaction to immune mediated disease?

Answer 20

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

Question 21

What is alopecia areata?

Answer 21

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

Question 22

What is feline psychogenic alopecia?

Answer 22

• 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