approach to scale

Scale def

Desquamated corneocytes on skin + hair

Causes of inc / path scaling

Abnormal desquamation (corneocyte shedding)

Abnormal cornification (outer epithelium layer)

Infl (inc keratinocyte turnover)

Bact + fungi enzymes

Adherent scale attached to what

Epidermis

Which is scale a or b

A

Primary scale def

Direct result of path

Secondary scale def

From skin infl, internal disease, external factors

Treating secondary scale

Treat primary disease, remove excess scale

Scale in back inf (progress)

Normal → pustule → scale, epidermal collarette → post infl hyperpigmentation

Bact inf in dogs - bact causing folliculitis + follicular pustule

Staph pseudintermedius

Bact inf in dogs - Epidermal collarette formation

Follicular pustule rupture → central hair loss → spreading circle of scale

Bact inf in dogs - Toxin affecting scale production

Exfoliative toxin

Ddx of primary scaling

Feline acne, canine ear margin seborrhea, primary seborrhoea, ichthyosis, zinc responsive dermatosis, vit a responsive dermatosis

Ddx of secondary scaling

Infl, endocrinopathies, diabetes mellitus, callus, idiopathic facial dermatitis, epitheliotropic lymphoma, sebaceous adenitis, exfoliated cutaneous lupus erythematosus, superficial necrolytic dermatitis, leishmaniasis, feline thymoma, FeLV, FIV, solar

Scale + pruritus means what

Parasites, bact inf, allergy

What to do if scale + pruritus (suspect Parasites, bact inf, allergy)

1- check for parasites

2- check for secondary inf

3- endocrine/ metabolic disease testing

4- biopsy

5- genetic testing

What to do if scale + pruritus (suspect Parasites, bact inf, allergy) - endocrine tests

Urinalysis, haematology, biochem

What to do if scale + pruritus (suspect Parasites, bact inf, allergy) - breeds for ichthyosis

Golden retriever, Great Dane, bulldog

What to do if scale + pruritus (suspect Parasites, bact inf, allergy) - breeds for epidermolytic hyperkeratosis

Norfolk terrier

What to do if scale + pruritus (suspect Parasites, bact inf, allergy) - breeds for lethal acrodermatitis

Bull terrier

What to do if scale + pruritus (suspect Parasites, bact inf, allergy) - parasite tests

Flea comb, trichogram, skin scrape, treatment trial

What to do if scale + pruritus (suspect Parasites, bact inf, allergy) - inf tests

Cytology, treatment trials

Zinc responsive dermatosis - type 1 disease

Genetically induced defective Zn GI absorption

Husky, malamutes, bull terrier

Zinc responsive dermatosis - Type 2 disease

Rapidly growing dogs fed Zn deficient diet

Giant breeds

Zinc responsive dermatosis - Primary lesion morphology

Erythema, pruritus

Zinc responsive dermatosis - Secondary lesion morphology

Scale, alopecia, suppuration, crusting, secondary bact inf

Zinc responsive dermatosis - Lesion distribution

Periocular, perioral, chin, ears, genitals, footpads, trauma sites

Zinc responsive dermatosis - Diagnosis

Parakeratosis in biopsy

Zinc responsive dermatosis - Treating type 1

Zn supplements (Zn sulphate), prednisolone

Zinc responsive dermatosis - Treating type 2

Diet

Ichthyosis - common breed

Golden retriever

Golden retriever ichthyosis - cause

PNPLA1-gene mutation → abnormal desmosome cleavage between corneocytes

Golden retriever ichthyosis - Pruritic?

No

Golden retriever ichthyosis - Lesion morpohoyl

Large flakes of non adherent scale, hyperpigmentation

Golden retriever ichthyosis - Lesion distribution

Generalised, ven

Golden retriever ichthyosis - Diagnosis

Rule out parasites

Biopsy

Genetic tests

Golden retriever ichthyosis - Treatment

Treat microbial otitis

Symptomatic treatment

Ear margin seborrhoea - breed

Dachshund

Ear margin seborrhoea - Pruritic?

No

Ear margin seborrhoea - Lesion morphology

White/ pigmented adherent scale, follicular casts

Skin fissures, secondary bact inf

Ear margin seborrhoea - Distribution

Pinna

Ear margin seborrhoea - Diagnosis

Rule out parasites, biopsy

Ear margin seborrhoea - Treatment

Emollients, Vaseline, propylene glycol

Surgical pinna margin removal

Feline thymoma/ nonthymoma associated exfoliative dermatitis - pruritiuc?

No

Feline thymoma/ nonthymoma associated exfoliative dermatitis - CS

Resp compromise

Feline thymoma/ nonthymoma associated exfoliative dermatitis - Lesion morphology

Diffuse erythema, scaling, alopecia

Feline thymoma/ nonthymoma associated exfoliative dermatitis - Lesion distribution

Generalised

Feline thymoma/ nonthymoma associated exfoliative dermatitis - Diagnosis

Biopsy, imaging

Feline thymoma/ nonthymoma associated exfoliative dermatitis - Treatment

Thymoma removal, immunomodulatory drugs (prednisolone, ciclosporin)

Feline idiopathic facial dermatitis - breeds

Persians, Himalayan

Feline idiopathic facial dermatitis - Lesion moroholy

Tightly adherent, greasy black scale, erosion, ulcers, exudate

Feline idiopathic facial dermatitis - Distribution

Face (eyes, muzzle, chin)

Feline idiopathic facial dermatitis - Diagnosis

Exclude parasites, inf, allergy

Cytology for malassezia overgrpwth

Feline idiopathic facial dermatitis - Treatment

Anti fungals

Keratolytic shampoos

Immunomodulation (cyclosporine, prednisolone, tacrolimus)

Feline acne - lesion morphology

Dark waxy/dry scale adherent to hair base, comedones

Feline acne - Distribution

Chin

Feline acne - Diagnosis

Rule out parasites

Malassezia overgrowth on cytology

Feline acne - Treatment

Antiseptics, antibiotics, topical keratolytics, prednisolone

Keratoplastic treatments - def

Reduce scale production

Keratoplastic treatments - Eg

Sulphur, coal tar shampoos

Keratolytic treatments - def

Remove scale

Keratolytic treatments - Eg

Salicylic acid

Moisturising + emollient products - def

After keratolytic/plastics to reduce transepidermal water loss + infl