Focal to multifocal- always assoc with inflamm disease 

Diffuse symmetrical alopecia

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Juvenile onset ( 4-10 mo) - localised or generalised ( >5 lesions), ears, feet, or secondary infection. presents with multifocal alopecia, scaling, comedomes. not really pruritic unless 2ndary malassezia present. generalised form needs treatment, local more likely to resolve with maturity. 

Adult onset- usually 2ndary ( cushings, hypothy., DM), can be idiopathic

- no need to treat it. 

• manage 2ndary infection
• Amitraz: dip once weekly- wash with keratolytic shampoo first- may get vomiting, sedation, bradycardia HUMANS: sedation, migraines and hyperglycaemia 
• Advocate ( imidacloprid/moxidectin) once weekly 
• ivermectin or moxidectin- build up dose gradually over 2-3 weeks- careful with collies
• milbemycin- well tolerated in even MDR positive dogs
• Treat until 2 negative skin scrapes 14-30 day intervals
• treat for a further month

 Dermatophytes are fungi that metabolise keratinised tissue. 

Microsporum canis

Microsporum gypseum

Dermatophytosis c.s

who are predisposed?

multifocal alopecia and scaling 

trichophyton is more inflamm. 

comedones

Follicular casts

Rarely pruritic

nodules

paronychia ( nail disease) 

yorkies and persian cats are predisposed. 

highly contagious and zoonotic, can remain in environment for over 18 months. 

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itraconazole in cats- alternating week-on-week off treatment- until 2 - negative cultures at least 7 days apart

- topical treatment is rarely effective alone

- chlorhexidine/miconazole ( malaseb) shampoo

- Enilconazole dip- care in cats

- environmental decontamination important! 

- clean and vacuum 

- clip long hair animals- facilitates topical treatment but can spread lesions- beware! 

Local dermatophytosis in young animals often resolves

endemic in mediterranean and Americas

- alopecia

- fine, silvery scaling

- depigmentation

- nodules

- erosions, ulcers, crusting

might see lymphadenopathy, hepatomegaly, splenomegaly- systemic 

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biopsy, serology, PCR

meglumine antimoniate, allopurinol (prevent from reproducing) and miltefosine

Anti sandfly products

- deltamethrin collars and shampoos

- permethrin spot on products

rare to uncommon

dermatomyositis and vasculitis

- involve extremities, periocular skin and bony prominences

- atrophic alopecia and scarring

- muscle atrophy

injection site

glucocorticoids, vaccines, drug reactions

may scar, might regress

older

bilateral Truncal alopecia

Comedones

Atrophic and inelastic skin

prominent blood vessels

calcinosis cutis

fragile skin and tearing is more common in cats. 

- variable c.s 

- alopecia with thickened, cool and hyperpigmented skin

- trunk or extremities

- most show partial alopecia with faded coat. abit younger 5-6 yrs old. 

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- caudal body and genitalia

- limbs, flank and neck

- sertoli cell tumours- more common in cryptorchid testes

- attractive to male dogs

- pendulous prepuce

- linear preputial erythema

hyperandrogenism: perianal gland hyperplasia, hyperpigmentation, seborrhoea

Hyperoestrogenism: Gynecomastia, vulval swelling, oestrus

-stress causes telogenisation of the coat

- body shutting down energy use for hair renewal

- exogen or grooming results in alopecia

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- events such as pregnancy, lactation , systemic illness cause the hairs to enter telogen. 

Anagen interruption

weakened hair shaft easily fractured

uncommon

Hair follicle  miniaturisation

yorkies

daschunds

familial disorder

- normal size but abnormal hair structure

hair follicles either fail to develop or shaft fractures

- see progressive hair loss at truncal, caudal and wear points.

- abnormal regrowth as well 

Can also see black hair follicle dysplasia and colour dilution

- often scaling and secondary infection which can be pruritic

alopecia[image]

- portugese water dogs, chesapeek bay retrievers, 

seasonal

linked to changes in day length

get follicular atrophy, hyperkeratosis and dyspasia

- avoid further damage to coat

- gentle anti-scaling and moisturising shampoos

- control 2 infections

- high quality diets and essential FAs

- sun protection

- melatonin, vit a ( promote normal follicular growth) 

alopecia of plush coated breeds ( chows, pomeranians, poodles) 

initially lose primary hairs

later complete alopecia and hyperpigmentation

spares extremities

Mitotain

GH 

Neutering or sex hormones

Deslorelin

 general skin and coat care

endocrinopathy, severe illness, spontaneous

follicular arrest?

Mainly inflamm, parasites and infection

cytology

bacterial culture

hair pluck: anagen and telogen, macromelanosomes

tape strip

exudate examination

skin scrapes

Woods lamp- fluresce

Fungal culture- ex. dermatophytes produce a red colour change that coincides with early fungal growth. ( saprophytes- later colour change) 

Biopsy- inflamm disease: early lesions, atrophic disease: late lesions

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Approach to symmetrical alopecia

hyperadrenocorticism stats

- hair pluck

- skin pluck- shaft abnormalities, macromelanosomes

Might see:

 polycythaemia

urinalysis: glucosuria

stress leucogram- lymphopaenia, eosinopaenia, mature neutrophilia

hyperglycaemia

increase AP

incrase cholesterol

increase TGs

hypertension

Approach to symmetrical alopecia

hypothyroidism stats. 

mild, non regen anaemia

hypercholesterolaemia

increased creatine kinase

urinalysis normal

Strong suspicion

low/low to normal TT4/FT4

equivocal thyroid tests

define cs at start

8-12 week trial should be curative

- perform post pill T4 after 4 weeks and adjust dose if needed 

parasites: staph, demodex, dermatophytosis, leishmania

IMD: Dermatomyositis, alopecia areata, vasculitis, 

endocrine/metabloic: steroid injection site

Congenital: keratinisation defects, sebaceous adenitis, follicular dysplasias

misc: post clipping alopecia, scars, traction alopecia

IMD: lymphocytic mural folliculitis (cats) 

Neoplasia: epitheliotrophic cutaneous T cell lymphoma 

Congenital: Follicular dysplasia, congenital 

Misc: cyclical flank, alopecia X