Dermatoses and the contribution of Diet (CANINE)

The skin and the coat accordingly are the mirror of the dog's health and quality of its food.

Skin is a major organ both in terms of surface area and roles (social, maintenance of inner skin, immune response. It is constantly rejuvenating itself the skin mobilizes a large part of the macro-and micronutrients provided by the food. An imbalanced intake of amino acids, fatty acids, vitamins or trace elements disrupts the barrier function and the immune protection provided by the skin.

The dog may become more sensitive to infection and can develop allergic reactions more easily .

RISK FACTORS

Risk of developing nutritional dermatoses are not only related to the quality of the food, but also to individual factors in the animal such as the physiological stage, the type of hair and the predisposition to certain metabolic or allergic diseases.

BREED SPECIFITIES

There are many breed-related predispositions that can be directly linked to nutrition. The two main groups of nutritional dermatoses (Zinc or vitamin A Responsive Dermatoses) are the majors causes of keratinization problems in predisposed breeds.

Deficiencies in intake :

Zinc responsive dermatitis- Nordic or large breeds

Vitamin A responsive dermatitis- Cocker Spaniel

Dietary Hypersensitivity:

Predisposition or over-representation- Labrador retriever

Predisposition associated with an atopic condition- American Staffordshire, Bull terrier, Beagle, German Shephard, Boxer, Bulldog, Dalmatian, Fox Terrier, Bull Terrier, Jack Russell Terrier, Labrador Retriever, Lhasa Apso, Pekingese, Sharpei, English Setter, Shih Tzu, West Highland Terrier.

Predisposed associated with malassimilations- German Shephard, Irish Setter, Sharpei, Soft Coated Wheaten Terrier

POSSIBLE SIGNS OF NUTRITIONAL DERMATOLOGY

- Dull Hair

-Widespread Scaling

-Localized or mucocutaneous keratoses (Growths often start out as small, rough areas. Over time, they tend to develop a thick, wart-like surface)

-Pruritus

-Recurring urticaria (Skin Rash)

-Chronic Otitis

-Recurring Pyoderma

NUTRIENTS THAT CAN INFLUENCE THE SKIN BARRIER FUNCTION

Polyunsaturated Fatty Acids e.g Linoleic acid --> They belong to the lipids produced by the sebaceous glands that form the hydrolipidic surface film

Proteins--> Sufficient intake of all essential amino acids is necessary for the synthesis of Keratocytes

Vitamin A--> Essential to the maturation of keratocytes and the formation of keratinous film layer

Biotin--> Essential to PUFA metabolism

Vitamin C--> Key role in the formation of the lipids of the keratinous film layer

Zinc--> Supplement helps reduce water loss and deficiency leads to corneogenesis (eye development) problems

Nicotinamide--> Increases the free fatty acid and ceramide concentrations in the keratinous layer (Outer skin layer)

Water Soluble Vitamins--> Participate in PUFA metabolism

Vitamin E--> Excreted by sebaceous glands, helps limit the oxidation of fatty acids

In dogs with a dense coat (e.g. Pomeranian, Spitz, Shihtzu), the quantity of hair is such that skin and coat maintenance and rejuvenation of the skin and coat accounts for 30-35% of daily protein requirements.

Dietary imbalances in animals with a dark or black coat may provoke the reddening of the coat. The level of Phenylalanine and Tyrosine needed to guarantee optimal coat pigmentation is twice that of the minimum requirements to ensure the puppy's optimal growth. Tyrosine supplementation in food helps increase the intensity of coat color.

AGE & PHYSIOLOGICAL CONDITION

These factors may influence the relationship between skin homeostasis, coat quality and food.

Immaturity of the immune system and high intestinal permeability may to some degree explain the prevalence of dietary hypersensitivities in the young animal. These phenomena may be more common during weaning.

Nutritional deficiencies appear more readily when the dog's nutritional requirements exceed simple maintenance requirements for eg. Chronic disease during gestation, lactation, and growth, an especially in large breed dogs. These deficiencies in protein, essential fatty acids and zinc, may result in keratinization defects

CONCURRENT DISEASES

Any disease that disrupts the assimilation of nutrients may have direct and indirect consequences on the quality of the coat and favor the development of concurrent diseases. Malassimilation (associated with dull and dry hair coat or even recurrent bacterial infections). Defective protein digestion may cause decrease in immune tolerance.

Exocrine pancreatic failure --> German Shephard

Protein- losing enteropathy and develop digestive hypersensitivities with pruritus, recurring pyoderma --> Soft Coated wheaten Terrier

Chronic digestive problems or prolonged used of antibiotics may also provoke a deficiency in vitamin B and a secondary deficiency in polyunsaturated fatty acids

Common Dietary Imbalances and Consequences:

Low-end generic Food --> Indigestible proteins, low fat content, mineral excess- Calcium and phytates (Particulars)--> Protein deficiency, Insufficient energy intake essential fatty acids deficiency (Consequences)--> Xerosis, keratoseborrheic conditions, generic dog food disease(Derma problems)

Home Prepared diet (improper supplementation)--> PUFA deficiency, Trace element deficiency (Particulars)--> EFA deficiency, zinc, Vitamin E deficiency of water soluble vitamins (Consequences)-->Xerosis, keratoseborrheic conditions (Derma problems)

Vegetarian diet--> Restricted protein intake, PUFA deficiency (Particulars), Sulfur amino acid deficiency, EFA deficiency (Consequences)--> Dull brittle coat, Xerosis, keratoseborrheic conditions (Derma problems)

Excessive mineral supplements--> calcium excess (Particulars)-->Zinc deficiency (Consequences)--> Generic dog food disease(Consequences)

SPECIFIC DEFICIENCIES

Vitamin A

Retinol deficiency causes a general keratinization problem, with scaling. Rarely it is also associated with visual deficiencies and digestive problems

Vitamin E

Covers two classes of fat soluble molecule. It is he form with the greatest biological antioxidant activity in the cell membranes.

Vitamin B

Water soluble and play a role as coenzymes for the cellular enzymes involved in energy metabolism and tissue synthesis. They are provided by food and some by gastrointestinal flora.

Riboflavin deficiency (Vitamin B2) --> Xerosis localized to the periorbital & abdominal regions.

Niacin Deficiency (Nicotinamide/vitamin PP)--> Food with low in animal nutrients, Pruriginous dermatitis of the abdomen and limbs

Biotin Deficiency (Vitamin B8 or H)--> In animals fed excess of egg whites which contain avidin which prevents absorption of this vitamin in the intestine. Erythema, Facial and periorbital alopecia, generalized scaling, leukotrichia, dull and brittle hair.

TRACE ELEMENT DEFICIENCIES

Mineral substances that act at very low concentration in the organism. Trace elements most directly relates to the beauty of the coat Iron, zinc, Copper

-Zinc: Deficiencies are typically caused by foods high in phytates (Chelate zinc). Foods of poor quality that are high in whole meal cereal containing a lot of bran. Also seen with foods of oversupplemented with calcium of in breeds with inability to absorb zinc. A simple deficiency can be controlled by rebalancing the diet and controlling secondary infection. Clinical diagnosis can be confirmed in a histopathological biopsy. Deficiency provokes immunity problems and keratinization with scaly, crusty periorificial thickening observed in the skin. Mainly characterized by major parakeratosis in the epidermis and follicles.

-Copper: Component of many carrier enzymes or proteins. Deficiency is observed mainly in puppies fed a homemade food without supplementation or with excessive zinc, calcium, or iron content. Deficiency causes to changes in coat with discoloration beginning in the face, and a thin coat with dull and brittle hairs.

ESSENTIAL FATTY ACID DEFICIENCY

- Linoleic Acid: Is abundant in most vegetable oils. Precursor or omega 6.

- Alpha Linolenic Acid: found in green vegetables, fruits, grasses, and plankton. The oils of fish from cold waters contain very high levels of two long chain fatty acids. Two long chains from alpha linolenic acid--> Eicosapentaenoic acid (EPA), Docosahexaenoic acid (DHA) these participate in fluidity of the cell membrane.

-PUFA: Production of eicosanoids (leukotrienes, prostaglandins), maintenance of skin barrier permeability, cholesterol metabolism and transport.

Deficiencies seen only in animals suffering from malassimilation or animals fed with poor quality diets or diets that have been over heated for a long period of time. The skin signs include xerosis, dull hair, and keratoseborrheic disorder.

OVERALL PROEIN DEFICIENCY

- Low quality or overcooked food will undergo modification due to Maillard (a chemical reaction between amino acids and reducing sugars that gives browned food its distinctive flavor) reactions and the digestibility will be reduced. Hair growth and the regeneration of skin mobilizes almost 30% of protein intake. Deficiencies lead to keratinization problems and diffuse alopecia with dull brittle air. Protein deficiencies are also observed in dogs presented with a chronic debilitating disease or pregnant dog's at the end of gestation or lactation, if the dietary intake is not adapted. Low digestibility of proteins may favor the development if dietary hypersensitivity.

SPECIFIC AMINO ACID DEFICIENCIES

- Aromatic amino acids: Tyrosine, Tryptophan

These are essential to the synthesis of the melanins responsible for hair pigmentation :Red, Brown, and black. A dietary deficiency leads to a lightening of the coat or the reddening of black hair

- Sulfated amino acids: Methionine, Cystine

Methionine and Cystine are essential to the growth of hair as they participate in the production of keratin. These amino acids are abundant in animal proteins and are rarely deficient in dog food, with the exception of non-supplemented vegetarian diets. Dogs are however less sensitive than cats to such deficiencies.

-DIETARY HYPERSENSITIVITIES

All the dermatoses caused by the ingestion of a food that provokes a harmful reaction in a healthy individual. Hypersensitivities/ Intolerances can be of non-immunological or immunological origin.

An immunological Hypersensitivity is a dietary allergy. The clinical manifestations are highly diverse and include gastrointestinal, respiratory, cutaneous, renal, or generalized involvement.

Non-immunological hypersensitivity. None allergic reactions are highly diverse. Some foods may cause urticaria or aggravate an atopic dermatitis if they are high in:

Histamine: Tomatoes, Spinach, Beef, pig liver, fresh crustacea, tuna, dry sausage, cheese

Histamine liberator compounds: Chocolate, strawberries, fish, pork, Ovomucoid

Tryptamine: Chocolate, Cooked cheese

-GASTROINTESTINAL ALLERGIES

The development of an allergic reaction depends on the nature of the dietary antigens, their presentation to the digestive immune system and genetic factors

Break in immune tolerance

Hypersensitivity reaction may be triggered by the following factors: Augmentation of intestinal permeability, Chronic digestive problems, high insoluble antigen content, and individual predisposition to hypersensitivity reactions

Dietary allergens

Majority of allergens identified in dogs are proteins of large molecular weight such as cow milk. Other causes are tomato and the Cryptomeria japonicum pollen.

Predisposing factors

Maldigestion

If digestion is defective, the quantity of antigens in the digestive immune system and their molecular weight is much greater, which can conducive to the break in intolerance. E.g a chronic intestinal inflammatory disease or exocrine pancreatic failure is conductive to the development of dietary hypersensitivity.

Intestinal Permeability Problems

Increase in intestinal permeability, by greatly increasing the quantity of allergens presented to the immune system, can break the conditions of tolerance and induce deleterious immunological reactions. The inflammatory reaction increases the intestinal permeability and vicious circle of maintenance of the phenomenon is maintained.

Atopy

Predisposes the animal to the development of allergic reactions, be they aeroallergens or dietary allergens .

Urticaria and Angioedema

Allergies to medication, vaccines or reactions to anrthropod bites. The ingestion of food that is high in vasoactive amines or anaphylactoid reactions. These vaccine reactions are due to dietary sensitivities to these same proteins, as some vaccinal allergic reactions are observed during initial vaccination.

Main allergy causes

Food Medication: Penicillin, Ampicillin, Tetracycline, Cephalexin, Vitamin K, Oxopirvedine, Vaccines, Diethylcarbamazine, amitraz, doxorubicin

Arthropod Bites: Bees, wasps, mosquitos, caterpillars, termites, spider crabs, fleas

Atopic dermatitis and atopic like dermatitis

Chronic pruriginous dermatitis of the face and extremities, characterized by a genetic predisposition to developing hypersensitive reaction to environmental allergens. Approximately 30% of atopic animals, the condition is significantly improved by an elimination diet. This suggests that dietary hypersensitivities could be considered as major factors in the etiology of canine atopic dermatitis. A hypoallergenic and highly digestible elimination diet is mandatory.

Common clinical signs:

 Age of first symptoms: between 6 months and 3 years

 Bilateral otitis externa

 Bilateral cheilitis

 Bilateral pododermatitis

 Steroid responsive pruritus

 Anterior erythematous pododermatitis

 Bilateral cheilitis

 erythematous or lichenified dermatitis of the large folds

 Hyperhidrosis

local or widespread malassezia dermatitis

LOCAL OR GENERAL PRURITUS

Dietary hypersensitivity may also manifest itself in the form of local pruritus. lesions generally consist of erythema associated with a self induced alopecia.

PYOTRAUMATIC DERMATITIS (Hot Spots)

Hypersensitivity is one of the causes of recurring hot spots. Diagnostic must be envisaged after the infection has been controlled, and the most common causes have been eliminated (Demodetic mange, flea allergy, dermatitis, lack of hygiene especially in dense undercoated breeds.

RECURRING SUPERFICIAL PYODERMA

Commonly atopy caused. Generally the lesions (papules, pustules, crusts, epidermal collarettes) are first observed in the regions of predilection: abdomen and inguinal legions. hey can spread all over the body. Clinical help is necessary with antibiotic the therapy is effective, but recurrence will be rapid after the antibiotic therapy has been stopped.

Diagnosis is based on identifying the lesions and conduction aa cytological test to find neutrophilic leukocytes with some evidence of cocci phagocytosis. Differential diagnosis is that of all recurring superficial pyoderma and comprises at least the exclusion of an ectoparasitic or another allergic dermatitis . Once all the causes of recurrence have been ruled out an elimination diet must be initiated .

Main causes or recurring pyoderma

Anatomical Faults: Folds, excessive humidity

Pre-existing Dermatoses: Ectoparasites, Keratinization problems, Allergic Dermatitis, Endocrinopathies

Iatrogen Causes: Glucocorticoid therapy, Irritating topical therapy, unadapted or too brief antibiotic therapy Immunodeficiency

METABOLIC DISEASES

-Migratory necrolytic erythema(Superficial necrolytic dermatitis, hepatocutaneous syndrome)

e.g: Hyperkeratosic ulcerated foot lesions, Ulcerated, crusty perioficial lesions, wide ulcers on the face with firmly attached scabs, perianal erosions

A serious dermatosis due to severe amino acid deficiency. It originates from chronic liver dysfunction (tumor, cirrhosis, functional failure or less commonly from pancreatic tumor. It is most often a deficiency of amino acid essential fatty acids, and zinc.

- Diagnosis is based on skin biopsies and the identification of the cause of the deficiency (Prolonged phenobarbital intake, biochemical imbalance, liver and pancreatic ultrasound biopsies.

- Which is why it is important to provide adequate food and supplement for your pet when they are on medication which triggers or degenerates other organs . e.g if a pain medication affects their liver add a bit of supplementation through food for the liver, so it can have the strength to process the medication and prevent faster deterioration.

-Nutritional Treatment of Necrolytic Migratory Erythema

These nutritional measures are associated with a discontinuation of antiepileptics, antibiotic therapy and administration of analgesics (Opioids), especially when the foot lesions affect mobility and coordination.

Amino acid intake 1 per 10 kg of body weight per day: Home- White cheese, egg yolk; clinic- slow intravenous infusion containing all essential amino acids at 10% per day

Polyunsaturated fatty acid intake: Home- Egg yolk, omega 3 fatty acid (fish oil)

Zinc intake: Zinc Gluconate 10 mg/kg/day *Math*; avoid zinc methionine as it is more hepatotoxic**

Treatment of infectious complication treatment: Clinic- Empirical Antibiotic Therapy e.g Cephalexin

Analgesics: Clinic- Opioid injection or patch

* Consult with your Veterinarian or Veterinarian Technician for proper diagnosis as well as portion information to prevent problems from over supplementation. Remember the purpose of supplementation is to aid in nutritional balance for healthy skin and coat. Excessiveness or Deficiencies cause an imbalance in nutrition thus the results can be zero to dangerous.

-Lethal acrodermatitis in bull terriers

A disorder of zinc metabolism. A gene problem, causes serious systematic symptoms including bronchopneumonia, bone deformities, cataracts and gastroenteritis. Accompanied by a severe immune deficiency and is fatal in all cases. Diagnosis is based on anamnestic data and histopathological confirmation. Supplementation is ineffective in this case due to the fact that it starts off severely and it's symptoms are difficult to control. e.g the body is acting similar to when a computer crashes; even after you restarted it and tried all the basic function to prevent it from crashing the computer just wouldn't respond and then BAM!! crash.

-Zinc Responsive Dermatosis (Type1)

This is not a genetic derived problem like the one above. It results from an abnormality in the intestinal absorption of zinc. Initial lesions are localized to the periorificial zones and the digits; Erythema, Scaling, which progress to firmly attached crusts. Pruritus is present in the case of secondary infections. The diagnosis must be confirmed by histopathological examination of a biopsy. The differential diagnosis is sometimes difficult as it also includes leishmaniasis in specific areas of the body, scabies, pemphigus foliaceous or dermatophysis.

Zinc supplementation is generally sufficient and a clinical improvement follows in less than a month. In case of failure, administration of low dose glucocorticoid therapy for three weeks will achieve a rapid improvement in clinical signs (e.g oral administration of prednisolone at*Math* 0.1-0.2 mg per kg per day for three weeks).

Zinc deficiency is found in foods high in phytates or calcium and low in essential fatty acids.

Food toppings which contain zinc

*Red Meats, Lamb, Pumpkin, Squash, flaxseed oil, white natural cheese, egg, Potatoes, Kale,

Treatment is usually life long and based on balancing the diet by administering zinc every three to four weeks. Keep in mind your pet's hypersensitivities.

Symptoms:https://iheartdogs.com/wp-content/uploads/2018/03/hairy-dog-feet-hyperkeratosis.jpg, https://topdogtips.com/wp-content/uploads/2019/10/My-Dog-Has-Crusty-Scabs-on-His-Back.jpg 

Conclusion

- Poorly balanced nutritional intake may generate spectacular dermatological imbalances. The most common are due to generic foods that are low in fat with excessive mineral supplementation, the most common being surplus calcium which inhibits the absorption of zinc.

-Nutritional dermatoses associated with general underfeeding, poor digestibility of the food or a gastrointestinal absorption problem. Nutritional deficiencies are rare, they may be observed in dogs fed with a poor-quality commercial food or an imbalanced diet.

- A correctly formulated commercial food stored in good conditions contains vitamins in sufficient quantities and supplementation is not necessary.

- The quantity of trace elements provided in the food does not correspond to the quantity actually available to the organism. Level of absorption depends on the chemical form in which they are provided and their dietary environment. There are interactions between different elements. Calcium absorption competes with the absorption of zinc, copper, and iodine. Trace elements provided in organic form chelated with amino acids their absorption is improved.

-Essential fatty acids are not synthesized by the organism. They must be provided with food as is the case with most vitamins. Precursors of PUFA, Omega 6 fatty acid and Omega 3 fatty acid

-Migratory Necrolytic erythema. There is breed or age predisposition. The patients are usually old. Dermatological legions are mucocutaneous and pedal in distribution and are characterized by erythema associated with major painful hyperkeratosis.

-The purpose of supplementation is to aid in nutritional balance for healthy skin and coat. Excessiveness or Deficiencies cause an imbalance in nutrition thus the results can be zero to dangerous.

-Lethal Acrodermatitis in Bull Terriers is a rare autosomal recessive genetic dermatosis. These breeds present poor general condition from a very early age -two weeks old; with erythematous and keratoseborrheic lesions in the extremities of the limbs and face. The digits are thicker.

-Zinc responsive Dermatosis this is not a genetic derived problem like the one above. It results from an abnormality in the intestinal absorption of zinc, most commonly seen in Nordic dog Breeds but not limited to other breeds such as Beaucerons, German Shepherds, Boston Terriers, Bull Terriers and Great Danes.

- Diagnosis of hypersensitivity is based on the elimination of other causes of pruritus (especially of infections and parasites) and the beginning of an elimination diet.

-Measuring of IgE to identify allergen is justified only in the case of an immediate pure allergy (e.g anaphylactic reaction)

Reference: Royal Canin Nutritional Encyclopedia for Dogs