SCALE - Keratinization Disorders Flashcards
What are scales?
Loose fragments of keratin debris
Why would scales form?
Form due to a problem with formation of keratin in keratinocytes or with formation of stratum corneum
List four steps for cornification to proceed normally.
Bundling of the keratin to establivh the corneocyte core.
Replacement of the cell membrane with a thick cornified envelope
Formation of lipid lamellar bilayers
Desquamation
Where is filament aggregating protein produced and brifely describe the formation?
Produced in the stratum corneum. Profilaggrin in keratohyalin granules breaks down to filaggrin.
What are epidermal lipids derived from?
Keratinocytes and sebaceous glands
Define epidermopoiesis
The production of new epidermal cells
Define keratinogenesis
Abnormalities in keratin synthesis and/or intradermal lipid synthesis
List 8 primary keratinization defects
Sebaceous adentitis
Idiopathic nasodigital hyperkeratosis
Ichthyosis
Zinc assoicated dermatosis
Lethal acro dermatitis
Vitamin A responsive dermatosis
Ear margin dermatosis
Feline acne
Describe two primary defects in formation of stratum corneum that can occur, leading to icthyosis
Increased stratum corneum production.
Decreased corneocyte desquamation
Describe an epidermolytic defect that leads to icthyosis and state which breed of dog this is prevelant in.
Suprabasal keratinocyte vaculoation due to mutations in epidermal keratins
List four nutritional factors that may cause scale formation.
Zinc responsive dermatoses
Hepatocutaneous syndrome (SND/NME)
Fatty acid defiency/responsive dermatosis
Vitamin A responsive dermatosis
Describe type 1 and type 2 zinc responsive dermatoses. (Age, breeds and how they interact with zinc)
Type 1 - Adult dogs, Husky, Malamute, American Eskimo, Samoyed, Unable to absorb zinc
Type 2 - Young dogs, Large breeds, diet low in zinc, high in phytate or calcium
Where on the body is zinc responsive dermatosis type 1 seen?
Periorbital, dorsal nose, lateral aspect muzzle, perioral, ventrla mandible, pinnae and footpads.
What are the three main general principles of the therapy and management for scaling disorders?
Address the underlying cause
Treat all secondary microbial infections
Topical therapy for scaling
Describe the topical therapy activities for scaling
Keratolytic activity: this causes damage to keratinocytes with subsequent shedding
Keratoplastic activity: this affects the kinetics of basal cell turnover
