Nutritional skin diseases Flashcards
What are clinical signs suggestive of a nutritional disorder?
scaling, crusting, alopecia, comedones, erythema, pruritus, and hair coat changes (dull, dry or greasy)
Protein deficiency: Hyperkeratosis, epidermal hyperpigmentation, loss of hair pigment; patchy alopecia with hairs that are thin, rough, dry and brittle; slow growing coat, increased duration of shedding; scales or crusts
What trichographic findings might you see to suggest a nutritional, endocrine, or metabolic disease is playing a role in your patient?
inappropriate numbers of telogen hairs; recall telogen is where growth stops
inappropriately curled, misshapen or malformed hairs suggest an underlying nutritional or metabolic disorder
What are ddx for breaking hairs?
DDx: nutritional disorders, dermatophytosis or congenitohereditary disorders (like color dilution alopecia)
What are ddx for unusual pigmented hairs?
external sources (salivary staining, chemicals, topical medications), nutritional disorders, color dilution/color mutant disorders, and endocrine
Hair is composed of ___% protein. The amino acid that is present in the hairs is ___.
95%; sulfur
__% of a patient’s daily protein intake is required for normal hair growth and keratinization.
25-30%
What percent dry matter is required for adequate protein ingestion in a dog or cat’s food?
dog: 25%
cat: 33%
Which amino acids can affect hair coat color?
aromatic amino acids such as phenylalanine, tryptophan, tyrosine
An amino acid deficiency can be remedied by supplementing with which amino acids?
arginine, glutamine, cysteine…also eggs/meat
How much amino acid deficiency is usually seen in patients with Superficial necrolytic dermatitis?
o Total serum amino acid levels frequently drop to 1/3 of normal
Greatest decreases in arginine, leucine, lysine, methionine, proline, threonine, and valine
Ski requires _____ and ___-rich keratohyalin granules in the stratum granulosum, else the epidermis is susceptible to amino acid deficiency
requires HISTIDINE and LYSINE-rich keratohyalin granules in the stratum granulosum
What were the conclusions from AJVR 2017 paper, Characterization of aminoaciduria and hypoacidemia in dogs with hepatocutaneous syndrome?
Hypoaminoacidemia in dogs with HCS prominently involved amino acids associated with the urea cycle and synthesis of glutathione and collagen. Marked lysinuria and prolinuria implicated dysfunction of specific amino acid transporters and wasting of amino acids essential for collagen synthesis. These findings may provide a means for tailoring nutritional support and for facilitating HCS diagnosis.
What situations has SND been correlated with?
phenobarbital administration, vacuolar hepatopathy, glucagonoma of the pancreas, intestinal disease
SND has been reported in which species?
humans, dog (shelties, wastes, cockers, scotties, shih tzu?), cat, black rhinoceros
What are the characteristic histopathologic and ultrasonographic findings of SND?
Marked parakeratosis (red) with inter- and intracellular edema (white) and hyperplastic basal cells (blue)
“honeycomb” or “Swiss cheese” pattern consisting of variable sized hypoechoic regions surrounded by hyperechoic borders
If the characteristic ultrasonographic findings are not observed in a dog with SND, what else should you look for?
drug history (phenobarbital), pancreatic tumor!
Lipids are rich in ___ acid which is key for ceramide production in the skin
Lipids are rich in LINOLEIC acid which is key for ceramide production in the skin
insulin stimulates/inhibits protein synthesis
insulin inhibits protein synthesis
Cotton fur syndrome in chinchillas is associated with which nutritional imbalance?
protein excess! Chinchillas require 15% protein, so if they have a diet >28% protein, they’re in trouble!
On halloween, you meet a cat who is reddish brown. what deficiencies do you suspect?
a) Tyrosine and phenylalanine deficiencies can turn a black cat into reddish brown - these are precursors to melanin
B) copper deficiency, since this it is required for tyrosinase
C) EXCESS zinc which can cause a relative copper deficiency
Deficiency or decreased ____ and ___ can result in weak wool of sheep
Decreased methionine or lysine= inhibited growth and weak wool fibers
Deficiencies of protein can cause guinea pigs to present with:
generalized alopecia
T/F: Saturated fats have 2+ double bonds and PUFAs have no double bonds
F: PUFAs have 2+ double bonds; saturated fatty acids have 0 double bonds
MCTs contain how many carbons?
8-12 carbons = medium chain
Which is an essential fatty acid:
a) oleic acid
b) linoleic acid
c) arachidonic acid
d) linolenic acid
e) palmitoleic acid
B linoleic acid and D linolenic acid
Which fatty acid is a precursor for eicosanoid synthesis?
arachidonic acid
List the EFAs in cats:
linoleic acid, linolenic acid, arachidonic acid
List the EFAs in dogs:
linoleic and linolenic acid
EFAs are highly saturated/unsaturated
unsaturated
You’re home-cooking your cat’s diet. Which of these oils MUST you include and why? Multiple answers possible
a) EVOO
b) Sunflower oil
c) corn oil
d) Coconut oil
e) cod liver oil
b) sunflower oil
c) corn oil, source of linoleic acid which is essential
The main dietary source of omega-3 fatty acids in pet food is: a) Linoleic acid b) linolenic acid c) alpha linolenic acid d) alpha linoleic acid d)
d) alpha linoleic acid
What are the metabolites of alpha linoleic acid?
Eicosapentaenoic acid (EPA)
Docosahexaenoic acid (DHA)
What are metabolites of linoleic acid?
Gamma-linoleic acid (GLA)
Dihomo-gamma-linoleic acid (DGLA)
Arachidonic acid (AA)
t/f: Omega-3 fatty acids compete with omega-6 fatty acids for the same metabolic enzymes, resulting in less production of and displacement of omega-6 fatty acids in phospholipids
T
This results in EPA in place of AA. Resultant EPA mediators (eicosanoids) are neutral, less inflammatory or anti-inflammatory
t/f: : eicosanoids produced from EPA can directly counteract those produced by AA
T
Evening primrose oil is which type of fatty acid?
linolenic acid source; O-6
Elongated to DGLA which directly competes with AA as substrate for cyclo-oxygenase and 15-lipoxygenase
Metabolism of DGLA results in formation of PGE1 and 15-hydroxy-8,11,13-eicosatetranooic acid – both of which have anti-inflammatory effects.
How does EPA decrease inflammation?
Metabolism of EPA by the lipoxygenase enzymes result in leukotriene B5 (LTB5) and 15-hydroxyeicosapentanoic acid
- Both are thought to counteract Leukotriene B4 (LTB4), which is more inflammatory.
Arachidonic acid is metabolized into two main classes of eicosanoids. What are they, and what do they do?
Prostaglandins: alter vascular permeability, potentiate vasoactive substances, modulate lymphocyte function, potentiate pain and pruritus
Leukotrienes: alter vascular permeability, activate neutrophils, modify lymphocyte function, and cause potent neutrophil and eosinophil chemotaxis
How much fat is required in dog food?
Canines need at least 3% of fat in canned food and 7-8% in dry food
How much fat should be in a pig’s diet?
1%; else swine parakeratosis which can be related to FA deficiency
What is “fur slip”?
Chinchillas with cutaneous signs of flaking, reduced hair growth, +/- pruritus and ulcers due to deficiency of LA and AA; can be caused by homemade diets or poorly preserved food or inadequate antioxidants and rancididty
Which EFA can be helpful in dogs with seborrhea sick?
linoleic acid; usually these dogs have high levels of oleic acid but low cutaneous levels of linoleic acid.
Why must vitamin A be administered with food?
it’s a fat-soluble vitamin, higher bioavailability when given with food
What are the 2 receptors for vitamin A?
- All-trans retinoic acid receptor (RAR)
- 9-cis retinoic acid receptor (RXR)
What effects does vitamin A have?
- Antiproliferative, but topical can induce desquamation through induction of EGF
- Anti-inflammatory effect via downregulation of nitrites and TNF-α
- Enhance wound healing; stimulating fibroblasts to produce TGF
- Inhibitors of Hair Growth (Inhibit Anagen, Induce Catagen, Prolong Telogen)
- Affect proteases, prostaglandins, humoral/cellular immunity, and cellular adhesion/communication
- Maintenance of normal reproductive and visual functions
Why do cats require preformed vitamin A?
Cats require preformed vitamin A because they can’t convert B-carotene to vitamin A
How Is vitamin A stored in the liver?
Stored in liver as retinyl palmitate
You examine a horse who’s been left to fend for it’s own nutrition. It’s been foraging only on barley for months.
What are signs in the equine of hypovitaminoses A?
- coronitis!
- night blindness, excessive lacrimation, reproductive problems, neurologic disorders
- rough, dull haircoat which progresses to alopecia, scaling and hyperkeratosis
You are examining a chameleon who has swollen lateral lip commissures, and both eyes are closed. He has halitosis. What questions do you ask next?
history of inappropriate diet? losing weight? dysphagia?
You are examining a chameleon who has swollen lateral lip commissures, and both eyes are closed. He has halitosis. What treatment do you start?
swab lips w/ chlorexidine and start vitamin A 2000 IU/30 g PO q 2 weeks
You are examining an Amazon parrot who is fed only seeds. What do you think is the cause of its hyperkeratosis, blepharitis and white plaques on oral mucosa.
hypovitaminosis A
Vitamin A is essential in caged birds to maintain skin and feathers.
Seeds are deficient in vitamin A
Amazon parrots are predisposed to vitamin A deficiency
What diet do you expect of turtles that predisposes them to hypovitaminoses A?
all-meat diets, especially captive terrestrial box turtles
Why are cats fed a high liver diet poorly groomed?
high liver diet leads to cervical ankyloses
What are signs of vitamin A deficiency?
Epidermal hyperkeratosis and scaling, occlusion of sebaceous ducts, papules associated with follicular hyperkeratosis, poor hair coat and alopecia; also reproductive failure, retinal degeneration and night blindness, increased susceptibility to infections
What are signs of vitamin A toxicity?
Epidermal scaling, unkempt hair coat, anorexia, weight loss, bone decalcification, liver damage
What are signs of vitamin D deficiency?
Rickets in young, osteomalacia in adults, chest deformity, poor eruption of teeth
What are signs of vitamin D toxicity?
Increased blood calcium levels, soft-tissue calcification, diarrhea, kidney failure, death
What are signs of Vitamin E deficiency?
Pansteatitis (seen in cats fed diets high in polyunsaturated fatty acids), seborrhea, muscular dystrophy, reproductive failure, intestinal lipofuscinosis, impaired immunity with predisposition to bacterial skin infections and demodicosis (dogs)
What are signs of vitamin E toxicity?
anorexia
What are signs of vitamin K deficiency?
Hemorrhage, poor clotting
What are signs of Vitamin C deficiency?
Rickets, impaired wound healing, bleeding, anemia, increased susceptibility to infections
What is another name for vitamin B1?
Thiamine
What are signs of thiamine deficiency?
Anorexia, weight loss, vomiting, dehydration, ventral flexion of neck, paralysis, incoordination
What’s another name for Vitamin B2?
riboflavin
What are signs of vitamin B2 deficiency?
Retarded growth, dry scaly skin, erythema, posterior muscle weakness, anemia, ocular lesions (pannus), glossitis, reduced fertility, testicular hypoplasia, fatty liver
What is another name for Vitamin B6?
Pyridoxine
___ is a component of xanthine oxidase that’s required for epithelial cell maturation, and considered nontoxic.
Riboflavin (vit B2)
What are signs of Niacin deficiency?
Blacktongue (pellagra), pruritic dermatitis, diarrhea, dementia, anorexia, anemia, emaciation, and death
What are signs of niacin toxicity?
cutaneous flushing, pruritus
___ is required for normal red blood cell development and DNA synthesis, and a deficiency in this can cause anemia, leukopenia, stunted growth, glossitis.
Folic acid
What’s another name for vitamin B12?
cobalamin
Vitamin ___ is required for synthesis of nucleic acids, involved in purine synthesis and CHO and fat metabolism.
B12/cobalamin
Biotin is also called ___
vitamin B7
Niacin is also called ____
vitamin B3
Which nontoxic water soluble vitamin is required for metabolism of fats and amino acids, essential for skin and hair health, functions in enzyme systems?
Biotin/Vit B7
Calcium toxicity can result in secondary deficiencies of which other minerals?
zinc, phosphorous, copper (interference with absorption)
Phosphorous toxicity can cause an EXCESS/DEFICIENCY of calcium.
Phosphorous toxicity can cause secondary calcium deficiency. also kidney damage, impaired skeletal development.
deficiency can be manifested as Rough hair coat, pica, anorexia, slow growth, rickets in young, osteomalacia in adults
