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Y4 SA dermatology > Alopecia > Flashcards

Alopecia Flashcards

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1
Q

What is alopecia?

A

▪Alopecia is the
– Loss of hair
– The absence of hair

▪Can be
– Partial* or complete
–Localised, generalised, symmetrical or multifocal
– A primary or secondary lesion

  • Hypotrichosis used synonymously by some – preferred for poor growth of hair not partial loss
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2
Q

History

A

▪Signalment
– Breed predisposition
▪Age of onset, duration, seasonality
▪Presence of pruritus
▪Contagion
▪History of travel
▪Signs of systemic disease
▪Drug history

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3
Q

What can age of onset, duration and seasonality indicate?

A

▪Congenital alopecias
▪Endocrinopathies middle age to older, chronic history
▪Cyclic flank alopecia increasing day length

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4
Q

What can the presence of pruritus indicate?

A
  • inflammatory alopecias
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5
Q

What can contagious alopecia indicate?

A
  • Dermatophytosis
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6
Q

What can history of travel indicate?

A
  • leishmaniasis
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7
Q

What can signs of systemic dz indicate?

A

▪Endocrinopathies, paraneoplastic alopecia, anagen/telogen defluxion

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8
Q

What can drug history indicate?

A

▪Injection alopecia, iatrogenic hyperadrenocorticism

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9
Q

Breeds affected by Alopecia X

A

Alaskan malamute
- Chow chow
- Keeshond
- Miniature poodle
- Pomeranian
- Samoyed
- Siberian husky

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10
Q

Breeds affected by breed associated follicular dysplasia

A
  • Chesapeake Bay retriever
  • Curly-coated Retriever
  • Dobermann
  • Irish Water spaniel
  • Portuguese water dog
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11
Q

Breeds affected by canine recurrent flank alopecia

A
  • Airedale
  • Bearded collie
  • Bouvier des Flandres
  • English and French bulldogs
  • golden and Labrador retrievers
  • Griffon Korthal
  • Schnauzer
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12
Q

Breeds affected by colour dilution alopecia

A
  • Bernese Mountain Dog
  • Chihuahua
  • Chow Chow
  • Dachshund
  • Doberman
  • Great Dane
  • Italian greyhound
  • Large Munsterlander
  • Newfoundland
  • Poodle
  • Pinscher
  • Saluki
  • Schipperke
  • Shelties
  • Silky terrier
  • Staffie
  • Whippet
  • Yorkie
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13
Q

Breeds affected by hyperadrenocorticism

A
  • Boston Terrier
  • Boxer
  • Miniature Poodle
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14
Q

Breeds affected by hypothyroidism

A
  • American pit bull
  • Beagle, Boxer
  • Cocker Spaniel
  • Dalmatian
  • English setter
  • German Wire-haired pointer
  • Giant schnauzer
  • Golden retriever
  • Maltese
  • OES
  • Rhodesian ridgeback
  • Sheltie
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15
Q

Breeds affected by pattern alopecia

A
  • Boston terrier
  • Boxer
  • Chihuahua
  • Dachshund
  • Greyhound
  • Miniature pinscher
  • Whippet
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16
Q

Breeds affected by sebaceous adenitis

A
  • Akita Inu
  • Belgium sheepdog
  • Border collie
  • Chow Chow
  • English Springer Spaniel
  • GSD
  • Samoyed
  • Standard poodle
  • Vizsla
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17
Q

Physical examination - character & distribution of lesion

A

Character of alopecia
▪ Partial/complete
▪Regular/irregular patches
▪Sharp/gradual edge

Distribution
▪Asymmetrical vs symmetrical
▪Focal/multifocal vs generalised
▪Other skin lesions
▪Erythema, hyperpigmentation, scaling, comedones, skin atrophy

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18
Q

Inflammatory ddx

A

Infectious agents
▪ Bacterial folliculitis
▪ Dermatophytosis

Parasitic
▪ Demodicosis
▪Leishmaniasis

Immune-mediated
▪Alopecia areata
▪ Dermatomyositis
▪Sebaceous adenitis

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19
Q

Non-inflammatory ddx

A

Hair follicle arrest
▪ Endocrinopathies
▪Alopecia X
▪ Telogen defluxion
▪ Paraneoplastic alopecia
▪ Cyclical flank alopecia
▪Post-clipping alopecia
▪ Injection alopecia

Hair synthesis defects
▪ Congenital alopecias
▪Pattern alopecia
▪ Follicular dysplasia
▪ CDA / BHFD
▪ Anagen defluxion/effluvium ▪Sebaceous adenitis

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20
Q

Why is sebaceous adentitis a ddx for both inflammatory and non-inflammatory alopecia?

A
  • early on in the dz process it is inflammatory
  • later on it is not, instead it causes a defect in the production of oils, the hair won’t come out of the follicle and you get hair breakage
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21
Q

Bacterial folliculitis - most common cause in dogs & cats

A

▪Staphylococcus pseudintermedius (and other commensal flora)

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22
Q

Bacterial folliculitis - CS

A

▪Focal to multifocal patches of alopecia
▪+/- pustules, crusts
▪Especially short-coated dogs = ’short- coat pyoderma’

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23
Q

Bacterial folliculitis - diagnosis

A

▪Impression smear cytology

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24
Q

Dermatophytosis - most common species affecting dogs & cats

A

▪Microsporum canis (zoophilic)

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25
Q

Dermatophytosis - less common species

A

▪Microsporum gypseum (geophilic; inhabits soil)
▪Trichophyton mentagrophytes (zoophilic ;reservoir rodents)
▪Trichophyton benhamiae (zoophilic; guinea pigs and rodents)
▪Only very rarely human ringworm (anthropophilic; reservoir people) causes disease in animal species.

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26
Q

Are all dermatophytes zoonotic?

A
  • yes
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27
Q

Zoophilic vs geophilic vs anthropophilic

A

Zoophilic – animal to animal

Geophilic – environment to animal

Anthropophilic – person to person

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28
Q

Dermatophytosis - mild dz CS

A
  • scale and associated alopecia ▪Multifocal patches often circular
    ▪typical size 4-6 cm
    ▪+/- hyperpigmentation
    ▪Follicular casts
    ▪Mostly non-pruritic
    – Not itchy unless get secondary bacterial infection
    ▪Often the head, ears and chin
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29
Q

Dermatophytosis - severe dz CS

A
  • multifocal alopecia becomes confluent and is complicated by secondary bacterial pyoderma
  • therefore do cytology even in proven cases
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30
Q

Which species of dermatophytosis is often more inflammatory? Which can it resemble?

A
  • Trichophyton
  • can resemble deep pyoderma clinically
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31
Q

Dermatophytosis diagnosis

A

Wood’s lamp examination
▪Warm for 5-10 mins, expose hair for 3-5 mins
▪ Apple green fluorescence of hair
▪ Most M. canis fluoresce, if done carefully

Trichography
▪ Arthrospores (soap bubbles) surrounding hair shaft, hyphae within hair, squashed & broken hairs

In house DTM
▪ False positives and negatives
▪ If get colour change quickly it’s the fungi eating the protein, but must be in the 1st few days of culture
▪ If get colour change later (e.g. 10 days later) likely to be something from the environment
▪ Difficult to do so don’t bother

External lab fungal culture (± PCR)
▪ Test of choice/gold standard

Sampling for culture best using a sterile toothbrush = Mackenzie Technique

DTM = dermatophyte test medium

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32
Q

Dermatophytosis - biopsy

A

▪Don’t prep the skin site
▪Send tissue with hair follicles
▪Deep wedge or excisional for nodular or indurated tissue, (debulk/excise nodules prior to treatment}
▪Alert laboratory to differential diagnoses – PAS / other fungal stains
▪In cases of nodular dermatophytic disease, biopsy is needed for diagnosis

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33
Q

Dermatophytosis - tx

A

▪ Can spontaneously resolve (12 -20 weeks)
▪ Clipping
▪ Topical treatment
▪ Environmental decontamination
▪ Systemic therapy

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34
Q

Dermatophytosis - spontaneous resolution

A
  • but should be treated to reduce environmental contamination and zoonotic risk
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35
Q

Dermatophytosis - tx - clipping

A

▪ Controversial (? in long coated breeds)
microtrauma may increase infection
▪ Remove a large number of the spores but also do tiny damages to the epidermis
▪ Particularly in Persian cats then means you can get subcortical dz or further infection in the hair follicles.

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36
Q

Dermatophytosis - topical tx

A

▪ Decreases contamination & speeds
clinical cure
▪ Chlorhexidine* / miconazole shampoo (2– 3 times a week)
▪ Enilconazole in dogs (not licensed in cats) every 4 days

  • Note Chlorhexidine scrub or shampoo by itself is not effective

These bring down the chances of the environment being contaminated but don’t penetrate into the hair follicle well so doesn’t treat the active infection. Itraconazole or ketoconazole for this.

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37
Q

Dermatophytosis - environmental contamination

A

▪ M. canis viable for up to 18 months
▪ Isolate animal to 1 room (ideally non- porous surfaces)
▪ Destroy bedding or disinfect (bleach, chlorhexidine), use protective clothing & daily vacuuming and disinfection: sodium hypochlorite (bleach) 1:10 solution

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38
Q

Dermatophytosis - systemic therapy

A

▪ Necessary to achieve mycological cure
▪ Itraconazole (cats & dogs), ketoconazole (dogs)
▪ Variable adverse effects of ketoconazole in dogs, so unlicenced itraconazole used by some authors
– Ketoconazole has lots of adverse liver and GI effects

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39
Q

Dermatophytosis - monitoring tx success

A

▪Monitor fungal culture every 2 weeks ideally using toothbrush technique
–Start when obvious reduction in clinical lesions
–Require two negative cultures 2 weeks apart to describe mycological cure
–False positives will be noted if continuing high levels of environmental contamination
–False negatives will be seen if very recent topical therapy before sampling

▪Once a week sampling used in some rescue catteries to increase throughput

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40
Q

Are demoted mites skin commensals? When do they spread?

A
  • Yes
  • Transferred from dam in early life
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41
Q

Demodicosis - follicular mites

A

= long bodied
▪Demodex canis (dog)
▪Demodex injai (dog)
– Massive ones
– tend to live on the. back
– cause a more greasy surface
▪Demodex cati (cat)

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42
Q

Demodicosis - surface mites

A

= short bodied
▪Demodex gatoi (cat)
– Causes very itchy skin dz
– Stands out because demodex (before secondary infection) is not contagious and is not itchy
▪Demodex cornei (dog) described
but is considered a variant of D. canis and not a separate species and should not be used

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43
Q

2 clinical syndromes of canine demodicosis

A
  • juvenile onset
  • adult onset
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44
Q

Adult onset demodicosis (why does it occur? CS)

A

▪Immunosuppressive disease
▪ Idiopathic
▪Localised becoming generalised
▪Often generalised
▪Often secondary bacterial infection
– Papules, pustules, draining sinus tracts, enlarged lymph nodes, +/- pyrexia
– Pruritic or painful
▪Require aggressive treatment
– For demodex whilst also trying to work out what is causing it
▪This is most often a manifestation of profound systemic illness – but demodicosis may precede overt signs
▪ Seen in cats, dog, humans & otters
– Causes death in otters as they can’t stay waterproof

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45
Q

Juvenile onset demodicosis (why does it occur? CS)

A

▪Immature immune system
– Allows over proliferation of the DNA in the follicles
▪Localised (<6 patches alopecia)
▪Generalised (> 6 patches, or includes the feet, often multiple body regions)
▪Localised to generalised patches
– Alopecia
– Scaling
– Blue-grey hyperpigmentation
– Comedones
– Follicular casts
▪+/- superficial bacterial infection
▪Mild cases spontaneously resolve

Alopecia, scale and erythema, comedones are obvious in most cases

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46
Q

When to treat juvenile onset demodicosis

A

Treat cases of localised disease when ▪Significant bacterial infection (antibiotic stewardship)
▪‘Accidentally if using isoxazolines for routine flea control
▪Not necessary for mild disease

47
Q

Demodicosis - diagnosis

A

Clinical appearance
▪Multifocal alopecia with follicular castings
▪Comedone formation
▪Secondary bacterial infection, often associated with peripheral lymphadenopathy
▪Malodour
▪Greasiness

Positive skin scrapings, hair plucks or biopsy

Reserve biopsy for areas with severe secondary changes (e.g. feet) or dogs with mucinosis (i.e. Sharpei)

48
Q

What do follicular casts indicate?

A
  • follicular dz
49
Q

What diseases are follicular casts common in?

A

▪Demodicosis
▪Dermatophytosis
▪Sebaceous adenitis

50
Q

What diseases are follicular casts less often seen in?

A

▪Bacterial folliculitis
▪Other diseases
– e.g early ECL
▪Can be seen by eye

51
Q

Where are hair plucks useful for?

A
  • feet and face
52
Q

If you see comedones what should you always do?

A
  • skin scrapings
53
Q

Underlying dz that could cause/exacerbate adult-onset demodicosis

A

▪Hyperadrenocorticism
▪Hypothyroidism
▪Diabetes mellitus
▪Systemic neoplasia ▪Immunosuppressive therapy
▪FIV / FeLV

Can also be iatrogenic -> use of steroids

54
Q

Idiopathic cause of adult-onset demodicosis

A

▪Hereditary mite-specific immune defect?
▪Lifelong treatment
▪Small number juvenile cases progress to adulthood

55
Q

Demodicosis tx (dogs) - if needed

A

▪Clip long haired animals, bathe to remove debris
▪Treat any secondary bacterial pyoderma
▪Treat ANY underlying immunosuppression
▪Anti-mite treatments
– Amitraz (Aludex®): licensed (not cats), not recommended
– Licenced isoxazoline drugs e.g. afoxolaner, flurolaner, sarolaner and lotilaner
– Imidacloprid/moxidectin (Advocate®): licensed, many have questioned the efficacy of this product in more severe cases
▪No need for environmental therapy
– As doesn’t live off animal
▪Treat until 2-3 consecutive negative skin scrapes taken every 4 weeks
▪Neuter female dogs with generalised juvenile onset demodicosis
– Increased chance of disease in offspring
– Periparturient reduction in immunity can result in return of disease (demodicosis has a genetic basis and most likely multiple genes are involved)

56
Q

What is generalised dz in demodicosis?

A

▪Disease in young dogs that does not self-cure?
▪Involvement of more than 6 areas?
▪Involvement of any feet?
▪A judgement call

57
Q

Demodex cati

A

▪Follicular mites
- rare cause of disease (c.f. dogs)

58
Q

Areas affected by localised demodex cati

A
  • eyelids
  • periocular
  • head or neck
  • ceruminous otitis
59
Q

Conditions causing a cat to be affected by generalised demodex cati

A

Immunosuppression, e.g.
- FIV
- FeLV
- DM
- HAC
- SCC in situ

60
Q

Demodex cati CS

A
  • comedones
  • alopecia
  • erythema
  • crust and scale
  • variable pruritus
  • secondary infection
61
Q

Demodex cati diagnosis

A
  • deep skin scrapes
62
Q

Demodex cati tx

A
  • Isoxazolines (e.g. Flurolaner (Bravecto spot-on) or Selemectin & sarolaner (Stronghold Plus)
  • Selemectin alone will not kill demodex
63
Q

Immune-mediated alopecia

A
  • sebaceous adenitis
  • dermatomyositis
  • alopecia areata
64
Q

Are immune-mediated alopecias common?

A
  • no
  • they are all rare
65
Q

Sebaceous adenitis (what it is/causes, breeds commonly affected diagnosis)

A
  • Inflammation of the sebaceous glands
  • Subtle loss of truncal hair becomes more generalised
  • Some dogs presented for pruritus (due to 2 ̊ infection) or severe scale
  • Marked follicular casting
  • Akita, poodle particularly affected
  • Diagnosis by rule outs and biopsy
66
Q

Dermatomyositis (what it is/causes, breeds commonly affected, diagnosis)

A
  • Loss of hair from face and bony prominences (may be ulceration)
  • Cellular immune-mediated damage to epidermis and muscles
  • Often collie breeds
  • Diagnosis by rule outs and biopsy
67
Q

Alopecia areata (what it is/causes, diagnosis)

A
  • Rapid hair loss followed by incomplete regrowth of white hair
    – the hair bulk contains large numbers of melanocytes, they get 2ndarily damaged in this so the hair grows back white
  • Presumed immune-mediated destruction of hair bulb
  • Trichogram: exclamation mark hairs
  • Diagnosis by rule outs and biopsy
  • Uncommon in dogs, common in Appaloosas
68
Q

What is the hair cycle regulated by?

A

▪ photoperiod
▪temperature
▪ hormones
– thyroid (+ve)
– growth hormone (+ve)
– oestrogen (-ve)
– corticosteroids (-ve)
▪nutritional status
▪general health
▪growth factors
▪drugs

69
Q

4 stages of the hair cycle

A
  • anagen
  • catagen
  • telogen
  • exogen
70
Q

What is exogen?

A
  • hair loss
  • 4th stage of the hair cycle
71
Q

Causes of hair cycle arrest

A

▪Endocrinopathies*
– Hyperadrenocorticism
– Hypothyroidism
– Hyper-oestrogenism: functional testicular/ovarian tumours
– Other sex hormone alopecias
▪Anagen/telogen defluxion
▪Paraneoplastic alopecia
▪Alopecia X
▪Cyclical flank alopecia
▪Post-clipping alopecia
▪Injection alopecia

72
Q

How do hormones influence the hair growth cycle?

A

 Changes in specific hormone ➔ telogenisation of hairs
 Failure of regrowth when lost

73
Q

Trichilemmal keratinisation in endocrine alopecia

A
  • Flame follicles
    – Caught in a strange catagen
  • Atrophic dermatopathy
    – Wide telogenised follicles with reduced numbers of glands and thin epidermis
74
Q

Endocrine disease – general dermatological features

A

▪Symmetrical to generalised alopecia
▪Dull and dry coat (± scale)
▪Comedones
▪Hyperpigmentation
▪Atrophic skin
– When pinch skin it stays there
– This is not true to hypothyroidism
▪Poor wound healing
▪Post-clipping alopecia / poor hair growth

75
Q

Affect of hyperadrenocorticism on skin and hair

A
  • Glucocorticoids effect on the skin➔catabolic and antimitotic effect
  • Decreased mitoses➔thinning, delayed wound healing, pilosebaceous atrophy
  • Inhibition of fibroblast proliferation, collagen and matrix substance production➔thinning, fragile vessels
  • Hair and glands reduced in size, so dry coat
76
Q

Affect of hypothyroidism on skin and hair

A

Thyroid hormone ➔stimulation of cytoplasmic protein synthesis & increase tissue oxygen consumption
* Initiation of anagen phase, wound healing
* Decrease hair cell apoptosis – prolonged anagen phase
* Promote matrix cell proliferation
* Support development of lymphoid tissue, neutrophilic function, B- and T- lymphocyte
function

77
Q

Cause of hyperoestrogenism (cause, characteristics, tx)

A
  • Sertoli cell tumour
    ▪More common in cryptorchid testes ▪Testicular discrepancy
    ▪Pendulous prepuce
    ▪Linear preputial erythema
    – But this is not always present
    ▪Feminisation syndrome
    ▪Metastasis rare (local ln)
    ▪Rare myelosuppression
    ▪Neutering curative
  • Also interstitial cell tumours and rarely seminomas, but not Leydig cell tumours which produce testosterone
78
Q

What is telogen defluxion (effluvium)?

A
  • sudden loss of hair
  • hairs are synchronised into telogen
  • shed as new hairs develop
79
Q

When does telogen defluxion occur?

A

Occurs 1–3 months post-
stressful incident
Pregnancy, lactation
Severe illness
Shock, surgery

80
Q

Telogen defluxion diagnosis

A
  • biopsy non-specific
  • need good history
81
Q

Cause of feline paraneoplastic alopecia

A
  • Pancreatic and bile duct carcinomas
82
Q

Signalment and CS of feline paraneoplastic alopecia

A
  • Older cats, often mildly systemically
    unwell
  • Alopecia of ventrum and legs
  • Skin shiny and translucent
83
Q

Tx & prognosis of feline paraneoplastic alopecia

A
  • Aetiology unknown
  • Surgical excision curative
    – Has to be early-stage disease
    – Referral surgery
  • Poor prognosis
    – Advanced disease at presentation
    – Hepatic metastasis
84
Q

Breeds affected by alopecia X

A

▪Plush coated breeds (Pomeranians, Chow chows)

85
Q

Aetiology of alopecia X

A

▪Unknown aetiology – local hormone aberrance?
▪genes coding for enzymes directly involved in sex hormones differentially regulated in alopecia X

86
Q

Alopecia X CS

A

▪Primary hairs lost first (puppy coat), later complete alopecia and hyperpigmentation
▪Spares extremities (eg. feet) and the head

87
Q

Alopecia X diagnosis

A

▪Diagnosis of exclusion
▪Rule out endocrinopathies
▪Biopsy – follicular dysplasia versus atrophic pattern – flame follicles common
▪Sex hormone alopecia profile
– Very difficult to interpret – not a diagnostic pattern

88
Q

Alopecia X tx

A

▪No consistently effective treatment
– Neutering in males – temporary
– Dry-needling
– Melatonin
– Deslorelin acetate implant
– A cosmetic disease
▪Avoid use of mitotane or trilostane as high risk of adverse effects

89
Q

Old name for cyclic flank alopecia

A
  • seasonal FA
90
Q

What is cyclic flank alopecia linked to?

A
  • changes in day length
    ▪Reduction in day length, follicular atrophy & dysplasia
    ▪Alopecia seen as day length increases
91
Q

Cyclic flank alopecia - CS, diagnosis, tx

A

▪Short coated bulldog, boxer type coat
▪Symmetrical as on both sides but not identical
▪Usually skin hyperpigmentation
▪Regrowth variable and can be progressive
▪Rule out HAC and hypoT4 – then skin biopsy
▪infundibular hyperkeratosis extends into 2 ̊ follicles, creating the shape of a witches’ foot
▪Melatonin used for treatment

92
Q

Pathogenesis of post-clipping alopecia

A

▪Unknown – some form of follicular arrest

93
Q

Breeds affected by post-clipping alopecia

A
  • plush coated breeds
94
Q

What do you need to rule out with post-clipping alopecia?

A
  • endocrinopathies
    – HAC often presents this way
  • severe illness
95
Q

Prognosis of post-clipping alopecia

A
  • good
  • usually regrowth within 6m
96
Q

Injection alopecia - pathogenesis

A
  • unknown
97
Q

Injection alopecia - CS & prognosis

A

Follicular atrophy with no inflammation (but may be immune mediated – vasculitis / panniculitis)
- Focal alopecia +/- hyperpigmentation & atrophy
- Usually local but may be remote from injection
- Glucocorticoids, vaccines (esp. rabies), depot antibiotics
- Usually spontaneously regresses
- May be permanent scarring
– As can be enough vascular damage to cause this

98
Q

What are the 4 hair synthesis defects?

A
  1. Congenital alopecia
  2. Pattern alopecia
  3. Follicular dysplasia
  4. Anagen defluxion/effluvium
99
Q

Congenital alopecia - what is it? breeds? prone to what?

A
  • Defect in hair follicles
    – Often associated with adnexal, epidermal, dental and nail defects
    – Dominant, recessive, X-linked
  • Hairless breeds e.g. Mexican hairless, Chinese crested, Sphinx
    – Dysplastic hair follicle can be prone to superficial and occasionally deep pyoderma (± sunlight damage)
    – UV protection needed
100
Q

Pattern alopecia - what is it? breeds? CS

A

▪Various syndromes – breed specific
– Later onset alopecia (2-3y+)
– Pre/post auricular, ventral neck, ventrum, caudal thighs
– Miniaturisation of hair
– Considerable concern for owners, but with low risk of secondary bacterial or yeast infections
▪Many breeds affected
– Yorkshire terrier (dorsal nose, ears and legs)
– Greyhound (back legs)
– Chihuahua
– Italian greyhound
– Dachshund (pinnae)
– Boston terrier
– Manchester terrier (bit of flank & face)

101
Q

Bald thigh syndrome in sighthounds - which breeds are affected?

A

▪Greyhounds and other sighthound breeds
– Whippets, Galgo Español, and Magyar Agár

102
Q

Bald thigh syndrome in sighthounds - aetiology, signalment & tx

A

▪Genetic component likely
– 2019 - structural hair shaft defects associated with downregulation of genes and proteins essential for hair differentiation (so not a pattern alopecia)
▪Any age and sex may be affected
▪No treatment
– No vigorous shampooing/rubbing/grooming as will make the alopecia a lot worse

103
Q

Bald thigh syndrome in sighthounds - CS

A

▪Bilateral hair loss on the caudal and lateral thighs
▪Alopecia may extend to the distal hind legs, the ventral abdomen and the chest and the ventral neck
▪May wax and wane

104
Q

Follicular dysplasia - Breeds affected?

A

▪Familial disorder
▪Irish water spaniel, Portuguese water dog, curly coat retriever, Airedale,
others

105
Q

Follicular dysplasia - CS, diagnosis, tx

A

▪Dysplastic hair follicles
– Hairs fail to develop
– Shaft fractures
– Loose hair where traumatised
▪Progressive hair loss
– Breed specific & wear points
▪Regrowth of abnormal hairs
▪Bald neck or looks like they’re wearing a bib
▪ Dysplastic hair follicles on biopsy
▪ Hard shampoo/tx can cause more damage

106
Q

Black hair follicle dysplasia - aetiology

A

▪Familial disorder
▪One or more genetic defects in
melanisation, e.g. incorrect transport of melanosomes into epithelial cells from melanocytes
▪Defect in pigmentation and hair formation

107
Q

Black hair follicle dysplasia- CS

A

▪Progressive changes
– Born normal, coat changes by 4
weeks
– Black hairs become dull
– Hair fracture and loss
▪Bacterial infection in some cases
▪Normal white hair & broken alopecic dark hair areas

108
Q

Colour dilution alopecia - aetiology

A

▪One or more genetic defects in melanisation
▪Macromelanosomes (melanin clumps cause hair fragility)

109
Q

Colour dilution alopecia - CS

A

▪Affects dilute colour coats
–Blue or fawn
– Established breeds with these colours rarely get this, e.g. Weimaraner, but the newer colours in breeds e.g. staffies, FBD, etc do
▪Progressive changes
–Hair fracture and loss
–Scaling
– +/- bacterial folliculitis

110
Q

Colour dilution alopecia - diagnosis

A
  • based on signs, trichography, rule outs and possibly biopsy
111
Q

Anagen defluxion (effluvium) - what is it?

A
  • Sudden hair loss
    – Chemotherapy
    – Severe illness
  • Damage to growing hair/follicle
  • Patchy to complete hair loss
    – Fractured/distorted hairs
  • Loss of whiskers
112
Q

Treatment – hair synthesis defects

A

▪Avoid damage to coat
– Hairs prone to breakage
– May induce superficial pyoderma
▪High quality nutrition (including essential fatty acid supplementation) ▪Gentle anti-scaling shampoos
▪Prevent/treat secondary bacterial infection
▪Protect from sun
▪Melatonin is suggested? Efficacy unproven

113
Q

When you see comedones what should you do and why?

A

comedones = blackheads
- skin scrape as it’s a follicular problem

Y4 SA dermatology (22 decks)

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