Scaling And Hyperkeratosis Flashcards by Mckenna Maloney

Scale

Or flakes is the build up of loose fragments (clusters) of the
stratum corneum
Due to disorder of:
-Maturation of the epidermis
- Glandular (sebaceous) secretion

How well did you know this?

Not at all

Perfectly

Crust

Composed of stratum corneum, fibrin, inflammatory & red blood cells - usually thicker than a scale

How well did you know this?

Not at all

Perfectly

Cornification

Process of stratum basale cells, requires atp, zinc or lack of can affect this process

How well did you know this?

Not at all

Perfectly

Epidermal turnover rate

20-25 days
Requires delicate balance between cell death & renewal

How well did you know this?

Not at all

Perfectly

Hyperkeratosis

Abnormal thickening of stratum corneum
Attempting to heal from insults or damage
Basal cells are stimulated to produce more daughter cells
Stratum corneum is replenished faster than it is desquamated
Can be part of the aging process - senile Hyperkeratosis on nose and footpads

How well did you know this?

Not at all

Perfectly

Primary Cornification disorders

Genetic abnormalities in cornification process
1. Ichthyosis
2. Canine primary seborrhea
Can be managed but not cured

How well did you know this?

Not at all

Perfectly

Secondary cornification disorders

Abnormalities caused by underlying disease
1. Scabies
2. Allergic dermatitis
3. Metabolic disease
4. Endocrine disease

How well did you know this?

Not at all

Perfectly

Scaling and hyperkeratosis

Majority (>90%) of scaling/HK is caused by underlying disease
Due to inflammation that stimulates epidermal turnover
Important to investigate & treat the underlying disease

How well did you know this?

Not at all

Perfectly

Canine Ichthyosis

Breed disposition - golden retriever, doodle, bulldog, jack Russell, Great Dane

How well did you know this?

Not at all

Perfectly

Cause of canine Ichthyosis

Genetic abnormality in formation of stratum corneum due to malformation of intercellular lipid
Onsets at younger ages

How well did you know this?

Not at all

Perfectly

Lesions of canine Ichthyosis

Large white to grey scales, most noticeable on ventrum but can be generalized
Pruritus is usually NOT seen UNLESS there is 2nd infection

How well did you know this?

Not at all

Perfectly

DX of Ichthyosis

Skin biopsy, genetic testing - clinical signs and flakes

How well did you know this?

Not at all

Perfectly

TX of Ichthyosis

TX is NOT curative - only targets symptoms and improves skin barrier function
Topical and systemic therapy
Topical
- kertolytic shampoo - exfoliating shampoo (SA acid/sulfur)
- moisturizers & Antimicrobials shampoo - chlorhexidine
- oil based spot treatment
Systemic - retinoids

How well did you know this?

Not at all

Perfectly

Canine primary seborrhea

Most common in cocker spaniels, springer spaniels and X, westies and terriers

How well did you know this?

Not at all

Perfectly

Cause of primary seborrhea

Increase in epidermal turnover rate - 7 days instead of 21d
Due to increase in BM cell division
Leads to abnormal cornification and desquamation
Can also affect basal cell lining ear canal and gland function

How well did you know this?

Not at all

Perfectly

Clinical features of primary seborrhea - skin lesion

Skin lesions present <1 y and progress in severity w age
- excessive scaling - generalized
- severe around mouth/eyes, pinnae, skin folds w excessive greasiness
- 2nd infection is common - yeast/bacteria
- follicular cast is also common

How well did you know this?

Not at all

Perfectly

Clinical features of primary seborrhea - otitis externa

Due to increased scaling in ear canal and cerumen +/- secondary infection

How well did you know this?

Not at all

Perfectly

Seborrhea sicca vs oleosa

Sicca - flakey skin appearence
Oleosa - greasy skin appearence

DX of primary seborrhea

EARLY onset, breeds
Skin lesions develop (usually) BEFORE pruruitis
Skin biopsy - non diagnostic bc there’s other causes of 2nd seborrhea w similar histopath - aka not specific

Tx of primary seborrhea

NOT curative
1. Control scaling - antiseborrheic shampoo - sulfur, SA acid
2. Control 2nd infection - topical or systemic meds
3. “Control” /attempt epidermal turnover rate w Vit A or retinoids

Sebaceous adenitis

Common in poodles, akitas, samoyeds, vizslas, havanese
Caused by destruction of sebaceous glands by cytotoxic T-lymphocytes

Function of sebaceous glands

Holocrine glands that open through a
duct into the infundibulum. Secrete oily emulsion called sebum that spreads over the hair shaft and skin
Functions of sebum:
-Glossy sheen, keeps skin/hair soft and pliable
-Permeability barrier
-Retain moisture
-Chemical barrier from pathogens

Sebaceous adenitis in long coat

Poodle, Akita, Samoyed
Darker or lighter hair color
Poodles: loss of curl
Excessive scaling or follicular cast
Poor and dull hair coats
Matting /clumping, partial alopecia

Clinical signs of sebaceous adenitis in short coat

Viszslas, dachshund
Multi focal annular areas of scaling and alopecia
Can progress/enlarge & turn polycyclic or coalesce to a large lesion
Moth eaten appearence

Key clinical features of sebaceous adenitis

Lesions first present dorsally head to lumbar and Dorso-ventral progression Lesions then progress to generalized distribution Pruritus varies from not present to severe 2nd infection can occur and contribute to or worsen puritus

DX of sebaceous adenitis

Skin biopsy - select lesions w abundant scaling/follicular cast

TX of sebaceous adenitis

Control scaling - antiseborrheic shampoo Cyclosporine Not all dogs respond to treatment and require life long Tx

Zinc responsive dermatosis

RARE chronic cornification disorder that responds to zinc supplementation. Two types

type I ZRD

Caused by a genetic defect in zinc absorption leading to impaired desquamation Breeds: Siberian husky, Alaskan malamutes can occur in others

Type II ZRD

Affects puppies fed w zinc deficient diet RARE today due to commercial diets

Clinical features of ZRD type I

Young adult onset (1-3) Tightly adherent THICK scales, Hyperkeratotic plaques Crusting lesions can develop

Distribution of ZRD type I

Face - periorbital, perioral, pinnae Pressure points on limbs (elbows, hocks) footpads

DX of ZRD Type I

Skin biopsy - select lesions with abundant thick adherent scales or hyperkeratotic lesions

TX for ZRD type I

1. Premium dog food 2. Zinc supplementation 3. Low dose prednisone may improve response

Malassezia dermatitis

Malassazia pachydermatis is NF on cats and dog skin Common areas: lip commissures, ext ear canal, interdigital skin and perineum (moist skin folds)

Clinical features of malassezia dermatitis

Excessive scaling ONE OF many skin lesions caused. Also includes: - erythema - self induced alopecia (due to pruritus) - hyperpigmentation and lichenification - greasiness (seborrhea oleosa) - rancid or foul smelling skin

Important clinical features of malassezia dermaitis

Smell is NOT specific to malassezia dermaitis - smells can develop due to bacterial or yeast infection

Underlying diseases that favor malassezia overgrwoth

1. Allergic dermatitis or allergic otitis 2. Intertrigo (esp in facial and vulvar folds)

DX of malassezia dermatitis

Skin CYTOLOGY Yeasts on cytology DO NOT correlate w disease severity Need to correlate clinical signs and skin lesions with cytology

TX of malassezia dermaitis

1. Location or otitis externa - topical antifungal shampoo/ointment/cream 2. Generalized - systemic antifungal (azole) + topical 3. Investigate underlying cause that could predispose and treat accordingly

Cutaneous lymphoma

Lots of names and lesions Rare in cats and dogs Dogs presentation is highly variable

Clinical features of cutaneous lymphoma

Periorbital Depigmentation, erosion, crust Exfoliative erythroderma SKIN BIOPSY IS A MUST - but which lesion ??

DX of cutaneous lymphoma

Take biopsy samples from - depigmented lesions - lesions w loss of architecture - erythematous & scaly lesions - plaques or nodules NEVER biopsy an entirely ulcerative lesion

TX of cutaneous lymphoma

GRAVE Px Treatment is palliative