Miscellaneous Flashcards
What is the epidermal cell renewal time in normal dogs?
Approximately 22 days
What is the most common acquired keratinization defect?
The callus
What percent water content was the skin be for it to appear and feel normal?
At least 10%
What are three important intercellular lipid components?
Sphingolipis, free sterols, free fatty acids
What is the optimal stratum corneum water concentration to promote softness and pliability?
20-35%
Seborrhea sicca
dryness of the skin and cat; focal or diffuse scaling of the skin with the accumulation of white to gray non adherent scales, the coat is dull and dry
Seborrhea oleosa
The skin and hairs are greasy and greasy keratosebaceous debris is best appreciated by touch and smell.
Seborrheic dermatitis
scaling and greasiness with gross evidence of local or diffuse inflammation
What are some causes of secondary canine seborrhea?
- Any disorder that alters cellular proliferation, differentiation or desquamation produced seborrheic signs
1) Inflammation can increase the DNA synthesis is the basal layer and stimulate epidermal proliferation; ex: too-vigorous grooming, demodicosis, dermatophytosis, cheyletiellosis, lice, low-grade contact dermatitis and early epitheliotropic lymphoma
2) Endocrine factors: hormones influence cellular proliferation and serum/cutaneous lipid profiles. Commonly seen with spontaneous/iatrogenic hypercortisolemia and hypothyroidism
3) Nutritional factors: uncommon cause as most dogs are fed a high quality, balanced diet; can be due to deficiency or excess or imbalance in glucose, protein, essential fatty acids and various vitamins/trace minerals. Intentional fatty acid deficiency for weight loss or control of pancreatitis or abnormalities in lipid metabolism.
4) Environmental factors: low environmental humidity, excessive bathing (especially with harsh products) and fatty acid deficiency can result in increased trans epidermal water loss . Low winter humidity
What breed is primarily reported with Vitamin A responsive dermatosis?
Cocker spaniels; also seen in Labrador retrievers and miniature schnauzers and other breeds
What are the clinical features of vitamin A responsive dermatosis?
- Adult-onset medically refractory seborrheic skin disease
- Marked follicular plugging
- Hyperkeratotic plaques with surface fronds
- Follicular plugging/hyperkeratotic plaques especially prominent on the ventral and lateral chest and abdomen
- Focal crusting, scaling, alopecia and follicular papule
- Ceruminous otitis
- Dry, dull, disheveled easily epilated hair coat is usually present
- Dogs are generally healthy otherwise
- A group of Gordon-setters were pruritic with a vitamin-A responsive dermatosis condition
- Histologically: profound and disproportionately marked follicular orthokeratotic hyperkeratosis
What are 7 conditions that can cause marked follicular plugging?
- Vitamin-A responsive dermatosis
- Hypercortisolemia
- Sebaceous adenittis
- True vitamin A deficiency
- Hypervitaminosis A
- Atypical generalized demodicosis
- Follicular dysplasia
What are primary differentials for generalized non-pruritic feline seborrhea sicca?
- Dietary deficiency (common for cats feeding fat a low fat diet or diet for hepatic lipidosis to develop a dull, dry and flaky coat
- Intestinal parasitism
- Low environmental humidity
- Diabetes mellitus
- Hyperthyroidism
- Cheyletiellosis
- Pediculosis
- Contact dermatitis or overzealous shampooing/powdering
What are primary differentials for localized and/or pruritic feline seborrhea sicca?
- Demodicosis
- Dermatophytosis
- lymphocytic mural folliculitis
What are differentials for feline seborrhea oleosa?
typically indicate severe hepatic, pancreatic or intestinal disease. drug eruption, SLE
What topical anti-seborrheic products should be avoided in cats?
- Tar
- Selenium sulfide
- Phenols
- Quarternary ammonium compounds
What are 12 differentials for nasodigital hyperkeratosis?
- In association with changes in nasal/pedal anatomy
- A senile change
- Congenitohereditary disorders of keratinization
- Distemper
- Leishmaniasis
- Pemphigus foliaceus
- Drug reaction
- Systemic lupus erythematosus
- Zinc-responsive dermatosis
- Generic dog-food dermatosis
- Necrolytic migratory erythema
- Cutaneous lymphoma
- Lesions restricted to nose: hereditary nasal hyperkeratosis of Labrador retrievers DLE, pemphigus erythematosis
- Lesions restricted to the paw pads: familial pad hyperkeratosis, papillomavirus infection
Feline acne
- Idiopathic disorder of follicular keratinization
- Start of as comedones; many will remain in this stage;
- Some will go on to develop papules and and pustules
- Can result in suppurative folliculitis, furunculosis, cellulitis
- Can be complicated by Pasteurella multocida, beta-hemolytic streptococci, staphylococci, Malassezia or dermatophyte
- Follicular cysts and scarring can occur in chronic cases
- Make sure to differentiate from dermatophytes, demodicosis and malassezia infection as well as eosinophilic granuloma.
- Consider heat packing with a magnesium sulfate solution
- Consider clavamox, fluoroquinolone or cepahlosporin as initial therapy if infection present, consider topical mupirocin.
What breeds are predisposed to ear margin seborrhea?
- Dachshunds
- Dogs with pendulous ears
- Sleeping near forced-air duct, wood stove or dry heat sources seems to increase the frequency/severity of the disease
- Consider salicylic acid-sulfur, benzoyl peroxide or benzoyl-peroxide-sulfur products
Canine tail gland hyperplasia
- All dogs have an oval spot on the dorsal surface of the tail
- Contains simple instead of compound hair follicles and contains numerous large sebaceous and circumanal glands (perianal hepatic) glands
- Pressure of hyper plastic glands on hair follicles induced atrophy
- With primary or secondary seborrhea, or elevate androgen levels, there can be hyperplasia of the sebaceous glands, circumanal glands or both.
- Strictly cosmetic problem
- Often occur due to hyperandrogegism
- If seen in a castrated male or female dog, consider underlying adrenal disorder or a functional tumor; consider altered sex hormone levels and prompt a complete adrenal evaluation.
Supracaudal organ
Additional glands located along a line on the dorsal aspect of a cats tail; this is rich in sebaceous and epitrichial sweat glands
In animals receiving no medications for a systemic or skin disease, what are 9 differentials for exfoliative dermatitis
- Ichthyosis
- Contact dermatitis to a topical agent
- Pemphigus foliaceus
- FeLV
- FIV
- SLE
- Erythema multiforme
- TEN
- Epitheliotropic lymphoma
- If an animal is receiving medication: consider drug eruption, iatrogenic or spontaneous hypercortisolemia
- Widespread bacterial folliculitis, demodicosis, dermatophysosi, Malassezia dermatitis, cheyletiella and occasionally scabies
Aside from exfoliative dermatitis, what other syndromes can a cat develop with thymoma?
- Myasthenia gravis
- Polymyositis
- Myocarditis
What are 7 differentials for erythroderma in dogs?
- Systemic lupus erythematosus
- Demodicosis
- Drug reaction
- Thallium toxicosis
- Mast cell tumor
- Cutaneous lymphoma
- Systemic mastocycotis
Paroxysmal flushing has been associated with this in dogs?
- Pheochromocytoma
- Drug reaction
- Mast cell tumor
- Carcinoid syndrome (uncommon condition associated with slow-growing malignant carcinoid tumors derived from enterochromaffin class that produce a variety of vasoactive compounds; seen in dogs with a pulmonary adenocarcinoma and intestinal lesions)
What drugs will cause exfoliation?
- Starting thyroid supplementation in a hypothyroid dog
- Stopping corticosteroids after prolonged treatment
- Starting to treat a Cushingoid dog.
Proliferative necrotizing otitis externa of Kittens
- only seen in kittens < 1 year of age (usually between 2 - 6 months of age); regress spontaneously between 12-24 months
- Histologically similar to hyperkeratotic EM
- Most affected cats appear indifferent to the lesions
- Histo: raised plaques are sharply demarcated from adjacent normal skin; scattered-apoptotic keratinocytes are present within a severely hyperplastic epidermis and follicular epithelium; there is striking parakeratotic hyperkeratosis intermingled with neutrophilic crusts, often in layers; process extends into the superficial hair follicles which are often dilated with keratin and neutrophils; true satellitosis is not seen.
- Affected keratinocytes are in a diffuse distribution and oftentimes adjacent to increased amount of keratin. These may in fact represent dyskeratosis
- Active luminal follicular pustulation may be present.
- Numerous eosinophils and neutrophils are present wthin the superficial and perifollicular dermis and intermingled with lymphocytes, macrophages and plasma cells.
What is the reported optimal ratio of N6 to N3 fatty acids to minimize production of the inflammatory mediator LTB4.
Between 5:1 and 10:1
What is meant by the term photothermolysis
- Tissue destruction that results from rapid and high heat formation.
Discuss low-level-laser therapy (i.e. “cold laser”)
- Light-emitting diodes with wavelengths in the visible red (~620-690 nanometers) to infrared wavelenghts (~720-1260 nanometers).
- Thought to result in photobiomodulation, that is the process of changing the nautral biochemical response of a cell or tissue within the normal range of its function to stimulate cell’ innate metabolic capacity to respond to a stimulus; when biomodulation occurs from a photon transfer, it is called photobiomodulation
- May stimulation cellular proliferation
- May normalize cellular responses and reduce inflammation in various diseases and promote healing
- Red wavelenghts (620-690 nm) for superficial treatments, infrared wavelenghts (720-120 nm) for deeper treatments.
List 5 advantages of CO2 laser therapy
1) able to address lesions in locations that would be tricky to perform cold-steel surgery
2) Less pain (seals nerve endings)
3) Less bleeding (seals small blood vessels and causes coagulation by defocusing the beam)
4) Less tissue destruction
5) Sterilizes surgical sites aside from viruses
What kind of itch is acupuncture proposed to work against?
- Neuropathic itch originating from the central and peripheral nervous system
- Does not benefit histamine-mediated itch
What wavelength is UVC radiation?
< 290 nm, extremely damaging to cells but does not typically reach earth’s surface because of ozone layer
What wavelength is UVB light?
290-320 nm
What wavelength is UVA light?
320-400 nm; penetrates deeper into skin than UVB and is the spectrum associated with photosensitivity reactions.
What wavelength of UV light is most damaging to the skin?
320-340 nm; within the UVA spectrum
What is phototoxicity?
Classic sunburn reaction, dose related response to light exposure.
What is photosensitivity?
When skin has increases susceptibility to the damaging effects of UVL because of the production, ingestion, injection of or contact with a photodynamic agent.
What is the pathogenesis of photoxicity?
Incompletely understood, but involves:
- epidermis
- blood vessels of superficial and deeper vascular plexuses
- UVB and UVC result in formation of vacuolated keratinocytes in the superficial epidermis, apoptotic keratinocytes, vascular dilatation and leakage and depletion of Langerhans and mast cells
- Increase in tissue levels of histamine, prostaglandins, leukotrienes and other vasoactive compounds, inflammatory cytokines, adhesion molecules and reactive oxygen species
