Cornification Flashcards
keratinization
genetic program of keratinocytes in the basal cell layer to mature, die, and produce the stratum corneum
cornification
keratinization + formation of lipid interstitium holding the dead keratinocytes together
scale
excess stratum corneum (dandruff)
crust
scale + blood, serum, micro-organisms, cells, etc
stratum basale
keratinocytes undergoing mitosis
stratum spinosum
keratinocytes begin to flatten
attached via desmosomes
stratum granulosum
production of keratohyalin and lamellar granules
keratohyalin
forms corneocytes
keratin + pro-filaggrin
lamellar granules
forms interstitium
ceramides, cholesterol, fatty acids
stratum corneum
corneocytes + filaggrin and ceramides
filaggrin
protein that holds together keratinocytes
deficiency can cause allergic dermatitis in the presence of microorganisms
what causes primary scaling/crusting disorders
breed-related
genetic
idiopathic
nutritional
congenital
what causes secondary scaling/crusting disorders
parasites
endocrine disorders
infectious
neoplastic
seborrhea
breed related scaling and crusting in dogs
affects trunk and pinnae (ceruminous otitis external)
erythema, pruritus, alopecia, rancid odor
what breeds are prone to seborrhea
cocker spaniels
persian cats
ichthyosis
rare, congenital, hereditary group of diseases leading to inability to properly form the stratum corneum
leads to excessive scale and crust
what breeds are prone to canine ichthyosis
norfolk terriers
golden retrievers
american bulldogs
great danes
Russell terriers
idiopathic regional cornification
hyperkeratosis and “fronding” of the foot pads and nasal planum
sebaceous adenitis
idiopathic granulomatous inflammation of the sebaceous gland leading to scaling and alopecia
can extend into the hair follicle
presentation of sebaceous adenitis in short haired dogs
circular regions of alopecia (geographic)
presentation of sebaceous adenitis in long haired dogs
entire segments of alopecia, rat tails, follicular casting
follicular casting
excess keratin around the hair shaft leading to waxy debris
zinc responsive dermatosis
parakeratosis + hyperkeratosis
resolves with zinc supplementation
ZRD syndrome I
crusting/scaling of mucocutaneous junctions (eyes, lips), elbows, and foot pads
- bilateral, not symmetrical
common in Siberian Huskies
ZRD syndrome II
crusting plaques (dermis and epidermis), fissuring of foot pads, fever, malaise
young dogs fed excess Ca or plant protein
any breeds
cattle ZRD
hereditary defect in zinc absorption from GIT
diarrhea, skin lesions, poliosis, decreased suckle reflex
inflammation and crusts around eyes, base of ears, coronary bands, muzzle
goats ZRD
caused by alfalfa (high Ca) or over-liming (Ca salts) leading to Zinc deficiency
crusts, bilateral symmetrical alopecia, rough hair coat, abnormal claw growth
swine parakeratosis
inadequate intake of zinc or excessive intake of Ca
RARE
thickened, encrusted, and fissured skin, poor growth
equine mane and tail seborrhea
scaling and crusting along the mane and tail
equine canon keratosis
excess stratum corneum deposited along the distal liumbs
equine linear alopecia
vertical lines of non-pruritic, non-painful alopecia
common in quarter horses
histology of linear alopecia
lymphocytic to granulomatous mural folliculitis (in follicle wall NOT lumen)
hyperkeratosis
