Keratinization Diseases Flashcards
Which breeds are predisposed to primary seborrheic dermatitis (inherited disorder of epidermal hyperproliferation)?
1) American Cocker Spaniels
2) English Springer Spaniels
3) West Highland White Terriers
4) Bassett hounds
Also Irish setters, Doberman pinschers, Chinese Shar-Peis, dachshunds, Labrador retrievers, GSD)
Which eicosinoids stimulate DNA synthesis in basal cell layer to induce epidermal proliferation?
Leukotriene B4 (LTB4) and Prostaglandin E2 (PGE2)
Which shampoo ingredients are the best “degreasers”, but also increase TEWL?
Tar, benzoyl peroxide (+/- sulfur), selenium sulfide
Which breeds develop vitamin A responsive dermatosis?
Cocker spaniels
Labrador retreiver
Mini schnauzer
others
(Different version ~pruritic~ in gordon setters)
Clin signs: comedones, hyperkeratotic fronds, ceruminous otitis. Follicular plugging
A 5 yo MN cocker spaniel presents with multiple comedones, follicular plugging, and hyperkeratotic plaques with surface fronds on his ears. Diagnosis?
Vitamin A responsive dermatosis
Where on the body does sebaceous gland dysplasia start?
Head, pinnae, dorsum
RARE DZ
Which type of diets has been associated with feline seborrhea sicca?
Low fat (weight reduction, hepatic lipidosis)
Which breed develops ear margin dermatosis (follicular casts, scale)
Dachshunds
(associated w/sleeping next to heat sources?)
What adnexa are hyperplastic in canine tail gland hyperplasia?
1) Sebaceous glands
2) Circumanal glands (esp when androgen levels are high!!)
If a castrated/spayed dog develops tail gland hyperplasia, what organ should you evaluate?
Adrenal gland
Possible functional tumor, altered sex hormone levels
Which adnexa are associated with stud tail in cats?
Sebaceous and epitrichial (apocrine) sweat glands
-Catteries, where cats can’t groom appropriately
-Not just intact males
What is the pathogenesis of thymoma associated exfoliative dermatitis in cats?
Thymoma activates autoreactive CD8+ T cells, that act on epithelial cells
In which cats is leukotrichia seem with thymoma associated exfoliative dermatitis?
Orange cats
Where on body does exfoliative dermatitis begin in cats w/thymoma?
Head/pinnae, the progress down the back
*Also develop clawfold seborrhea
What histopath findings are associated with thymoma associated exfoliative dermatitis in cats?
-Cell-poor to cell-rich interface dermatitis with CD3+ or CD8+ lymphocytes
-Hydropic degeneration of basal keratinocytes
-Apoptotic keratinocytes throughout epidermis
-Mural interface folliculitis
-Sebaceous adenitis
-Severe laminar orthokeratotic hyperkeratosis
What is the treatment of choice for nonthymoma-associated exfoliaitve dermatitis?
Immunosuppressive steroid, atopica
In addition to exfoliative dermatitis, what other paraneoplastic syndromes have been reported in cats?
1) Myasthenia gravis
2) Erythema multiforme
3) Multifocal noninflammatory alopecia
4) Pemphigus
5) Myocarditis
6) Polymyositis
7) Granulocytopenia
*Likely also immune mediated from abnormal maturation/selection of T cells in neoplastic thymus
Which body regions are SPARED in large plaque parapsoriasis (1 dog, 1 cat)? What is the treatment?
Clin signs: widespread erythematous, scaly plaques that SPARE the head, pinnae, and distal limbs
Tx: Immunosuppressive GC
Which internal malignancies are associated with paroxysmal cutaneous flushing? (Red skin d/t vasodilation from vasoactive compounds)
1) Carcinoid syndrome (GI tumor of enterochromaffin cells OR pulmonary adenocarcinoma)
2) MCT
3) Pheochromocytoma
4) Drug reaction
Why can steroids be beneficial in greasy dogs?
Atrophic effects on epidermis and sebaceous glands
What concern do we have with prescribing retinoids?
Highly teratogenic
Which feline breeds develop primary seborrhea? Mode of inheritance?
Persians, Himalayans, Exotic shorthair cats
-Autosomal recessive (seen within 3d after birth)
A 1 yr Persian or Himalayan cat presents for nonpruritic, adherent black exudate on their skin/hairs around their periocular, perioral, and chin regions. What’s your diagnosis?
Idiopathic Facial Dermatitis of Persian and Himalayan Cats
A 4-12 month old Bengal cat presents for dry/scaly nasal planum that progresses to hyperkeratosis and fissuring. It can spontaneously resolve, but did not in this cat. You diagnose this cat with ulcerative nasal dermatitis of Bengal cats. Which treatments do you recommend?
Oral GC vs topical salicylic acid
What is the diagnosis for a FEMALE (X-linked?) rottweiler, siberian husky, or labrador retriever with accumulation of keratosebacoues debris on muzzle, legs, flanks + hyperkeratotic, hyperpigmented verrucous papules and plaques following Blaschko lines. NORMAL footpads, nasal planum.
Follicular parakeratosis
Which breed is thought to have a Malassezia hypersensitivity, resulting in epidermal dysplasia (lichenified, greasy coat along face, ears, legs, paws, ventrum)
West Highland White Terriers
(Autosomal recessive?)
What breed is affected by psoriasiform-lichenoid dermatosis?
English Springer Spaniel
What triggers psoriasiform-lichenoid dermatosis?
Exaggerated response to Staphylococcal pyoderma
Where on the body do English Springer Spaniels initially develop erythematous plaques with Psoriasiform-Lichenoid Dermatosis?
Pinnae, external ear canal, inguinum
Then spreads to face, ventral trunk, perineal region
What histopathologic features would you expect to see in a 1 year old English Springer Spaniel with multifocal erythematous plaques on his pinnae 2’ a Staphylococcal hypersensitivity?
1) Psoriasiform epidermal hyperplasia
2) Lichenoid interface dermatitis
3) intraepidermal eosinophilic and neutrophilic (Munro) microabscesses
Which breed develops prominent comedones and crusted papules along their dorsum, most severe at the midspinal region?
Mini schnauzers
“Schnauzer comedo syndrome”
Treatment for Schnauzer Comedo Syndrome
-Acne pads (alcohol, salicylic acid)
-Benzoyl peroxide baths
-Isotretinoin
-Treat 2’ infections
Gene associated with footpad hyperkeratosis in Dogue de Bordeaux?
Keratin 16
(some dogs have spontaneous improvement with age)
Gene associated with footpad hyperkeratosis in Irish terriers and Kromfohrlanders?
FAM83G
Gene that caused footpad hyperkeratosis in 1 rottweiler?
DSG1
Gene that causes Hereditary Nasal Hyperkeratosis/Parakeratosis?
SUV39H2
Breeds that develop Hereditary Nasal Hyperkeratosis/Parakeratosis?
Labrador retriever > greyhounds
Which protein is decreased in patients with a mutation in SUV39H2?
Loricrin
What are the 4 general etiologies of seborrhea in horses?
1) Primary- genetic
2) Inflammation
3) Nutritional factors
4) Environmental factors (low humidity environments, excessive bathing)
Which areas on the horse are most affected in primary seborrhea?
Mane and Tail
(Thick, waxy scale)
Which disease in horses causes vertically oriented bands of hyperkeratotic plaques on the shoulders, neck, and lateral thorax?
Linear keratosis
(Genetic?)
Which horse breeds are most prone to linear keratosis? Age of onset?
-Quarter horses
-Thoroughbreds
-Standard breds
(Rare in ponies)
Onset: soon after birth
What is the etiology of cannon keratosis in horses?
Idiopathic
No need to treat, but present for life
What is the age of onset of cannon keratosis?
Middle to old age
Cranial surface of rear cannon bones
Which breeds of cattle develop Ichthyosis fetalis (severe form)?
Norwegian Red Polls
Fresians
Brown Swiss
Calves die at birth or within a few hours
Skin is alopecic, covered in thick scale, fissures. Skin around lips, eyelids, anus are everted
Which breeds of cattle develop ichthyosis congenita (milder form)?
German Pinzgauers
Jersey
Holstein
Chianinas
Hyperkeratosis and alopecia develop over a few weeks
Microtia and cataracts
Which breed of cattle develops congenital dyserythropoiesis and dyskeratosis?
Polled Herefords
Small at birth, prominent foreheads
Hyperkeratotic muzzles w/”dirty face” appearance
Wrinkly/kinky haircoat, easily epilates
Starts on muzzle, pinnae, and progresses to generalized
Other clin signs: exercise intolerance, anemia, failure to thrive, death by 6 months old
Dyskeratosis means apoptosis of epidermal and follicular keratinocytes
Which breeds of cattle develop Hereditary Zinc deficiency?
Friesians
Danish Black Pieds
Shorthorns
Holstein
Angus
Age of onset of hereditary zinc deficiency in cows? Mode of inheritance? Prognosis?
Onset: 3-8 weeks
MOI: Autosomal recessive
Prognosis: die by age 6 months if untreated (hypoplasia of thymus, LN)
Marked diffuse parakeratotic hyperkeratosis
Pathophysiology of hereditary zinc deficiency in cows?
Intestinal malabsorption of zinc
Which large animal species can develop psoriasiform dermatitis?
Goats
Erythema and scale –> progress to crusts, thickened skin, alopecia
Waxing/waning
Onset: 3-5 months -> young adults
Which breeds of goats are affected by psoriasiform dermatitis?
Pygmy
Alpine
