The Definition, Uses, And Benefits Of Quercetin For Dogs

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What is Quercetin for Dogs?

Quercetin is a natural plant pigment or flavonoid found in plants. Quercetin for dogs offers extensive antihistamine, anti-inflammatory, and antioxidant properties. 

Fruits and vegetables with rich pigment boast a high concentration of quercetin. Some pet owners consider quercetin a natural dog antihistamine that is an excellent nutritional aid for pets suffering from allergies or sensitive skin. 


The Uses of Quercetin for Dogs

Quercetin is often referred to as nature’s Benadryl as it helps to regulate the body’s histamine response associated with allergens and inflammation. Histamines facilitate a hypersensitivity reaction that creates redness, swelling, itching, and sometimes even pain.

Allergies often require a multimodal approach to regulate an overreactive immune system. Owners may not need as many prescription medications when using quercetin for dog allergies. 

The itching related to allergies leads to many secondary issues due to self-inflicted trauma from chronic scratching, biting, and licking. Bacterial and fungal infections can cause dermatitis, resulting in discomfort. Allergies affect a pet’s quality of life and health and become very frustrating for owners.  

Some research shows that along with antihistamine properties, the quercetin flavonoid also contains antioxidants and polyphenols that show promising results in limiting the growth of specific cancer cells. 

Quercetin use in canine mast cell tumors shows promising results because of its specific antihistamine properties. Mast cell tumors present commonly as skin cancer but can also occur in the spleen and liver. The tumor has multiple mast cells that release histamines resulting in stomach ulcers, rashes, or even breathing problems. 

Additional quercetin applications include weight management, cardiac condition management, and bone health support. Quercetin lowers blood pressure and decreases the effects of low-density lipoproteins, known as bad cholesterol. 

The Correct Quercetin Dosage for Dogs

Owners must consult a veterinarian to discuss how much quercetin for dogs will provide a safe and effective result. It is also essential to list any other medications your pet takes to ensure no contraindications.

A conservative quercetin dosing guideline is 0.0002 to 0.0004 ounces per pound of body weight (5 to10mg per 0.45kg). The dosing interval is twice a day, ideally an hour before feeding time or at least three hours after a meal. 

Are There Any Known Side Effects?

When using quercetin for dogs, side effects may include gastrointestinal symptoms like nausea or a depressed appetite. 

Owners can avoid these side effects in sensitive pets by not feeding quercetin on an empty stomach. It is essential to monitor a pet closely when starting any new medication. 

Is Quercetin Safe for Dogs?

Holistic medications often offer a great alternative to scheduled drugs if your pet is the right candidate. It is always a good idea to discuss any supplements or medications with your pet’s regular vet to ensure there are no contraindications if your pet suffers from any underlying health concerns, such as kidney conditions. 

Safe sources of quercetin include the following:

  • Registered supplement products from reputable manufacturers.
  • Fruit and vegetables include blueberries, peppers, raspberries, dark leafy greens, apples, and broccoli. 

Onions and grapes contain high levels of quercetin but are toxic to dogs, so do not include them in your dog’s diet. 

Stray dog

FAQs about Quercetin for Dogs

Can Dogs Take Quercetin If They are Pregnant or Lactating? 

Unfortunately, researchers have not established the safety of quercetin in pregnant or lactating bitches, so they do not recommend it for breeding dogs. 

What is a Good Quality Quercetin Product? 

Owners should always seek out reputable producers of holistic medications. Companies should source supplement ingredients responsibly, and it is best to ensure that products undergo purity testing through a third-party company to validate their product quality. Always check the concentration of holistic medication and follow the dosage instructions carefully. 

What Should Owners Avoid in Quercetin Products? 

When purchasing quercetin products, ensure that there are no harmful additives or fillers. 

Ingredients to avoid in supplements include sorbitol, cellulose, artificial sweeteners or flavorings, food colorants, and preservatives such as sulfur and selenium.

Is it Safe to Give Dogs Formulations of Quercetin with Bromelain?

There are no known contraindications for giving both products together. Several products combine quercetin with bromelain for dogs. Bromelain is a proteolytic enzyme with an additional function. 

Combining quercetin and bromelain for dogs with allergies works synergistically to improve the quality of life for dogs suffering from chronic inflammation. 

The Benefits of Using the Product

The benefits of quercetin for dogs revolve around three main effects, according to research at the University of Maryland. Benefits result from combining histamine level regulation, antioxidant protection, and inflammatory response mediation. 

Seasonal and Environmental Allergy Regulation 

The introduction of allergens from the environment leads to an overreaction of the immune system in specific individuals with allergies. 

The immune system recognizes the foreign allergen as a threat and releases histamine molecules to clear the danger, which results in an allergic reaction. Increased blood flow to the affected site leads to swelling, redness, and irritation that can manifest as itching, sneezing, or watery eyes. 

Quercetin helps to manage histamine release and avoid an overreaction from the immune system. The management of histamine levels decreases the severity and frequency of allergic reactions. 

Respiratory Health Benefits 

Pets that suffer from respiratory conditions related to allergies can benefit significantly from quercetin. Adverse upper airway allergy responses like bronchoconstriction or increased mucus production become drastically reduced when the body regulates histamine release. 

Antioxidant Actions of Quercetin in Dogs

Quercetin minimizes the number of free radicals that circulate in the body after normal metabolic processes. Oxidative stress alleviation supplied by antioxidants helps the body reduce free radical damage. 

Multimodal Medication Approach

Many pets with allergies often need immunosuppressive or immunomodulatory drugs. Some medications, such as corticosteroids, come with multiple side effects, so some vets may choose to use quercetin to decrease the frequency or dosage of certain medications. 

Nutritional support is essential in dogs with allergies. The correct ingredient blend offers support and nourishment to the dermis, especially when compromised and itchy. Ingredients that soothe and strengthen the skin barrier against allergens help reduce itching and introduce secondary skin infections.

Discuss these options with your attending veterinarian before adding or adjusting your pet’s medications.  

The Different Types of Canine Allergies

The immune system is the body’s defense against pathogens; unfortunately, some individuals’ immune systems develop an inappropriate response that leads to excessive activity. The body’s immune system overreaction is known as a hypersensitivity reaction. 

Canine allergies fall into the Type-1 class of hypersensitivity reactions. The mechanism of Type-1 immune reactions involves mast cells and IgE antibodies. Allergens bind onto immunoglobulin-E (IgE) and trigger an IgE-mediated response that results in either a local or generalized reaction. 

The combined allergen and IgE bind onto a mast cell or a basophil, which results in a mass release of a mixture of inflammatory mediators, including:

  • Histamines.
  • Leukotrienes.
  • Proteases.
  • Cytokines.

Some inflammatory mediators affect the smooth muscle and vascular system, leading to dilating blood vessels, increased blood flow, and contraction of specific muscles in the affected area. Eosinophils are white blood cells forming part of the inflammatory pathway, drastically increasing circulation to the reaction site during a Type-1 response.

Symptoms seen with allergic reactions range from redness due to increased blood flow, swelling, and hives, or in severe allergic reactions, some dogs may go into full anaphylaxis.

Localization of Allergy Types

Allergy classification depends on how or why the allergic reaction takes place. The following categories influence an allergic reaction:

  1. Allergen-related hypersensitivities occur when patients become exposed to an antigen their body recognizes as a threat. When the allergen presents itself a second time to the immune system, the body mounts a response to target the allergen and destroy it. Flea saliva or specific proteins are good examples of allergens that dogs become allergic to.
  2. The route the allergen enters the body through affects the localization and manifestation of symptoms. Contact allergies manifest in the area exposed to the allergen, such as the skin, and inhaled allergens result in breathing difficulties.
  3. The onset of an allergy affects the severity of the reaction, and immediate hypersensitivities are more dangerous than delayed hypersensitivities. 
  4. The clinical symptoms localize around the affected area and help determine the allergen’s origin. Gastrointestinal symptoms, dermatitis, or bronchitis are common allergy-related side effects. 
  5. Atopy and endocrine disorders can be inherited and are challenging to treat and diagnose without extensive testing and costly medications. 

Environmental Allergies

The cause of allergies in dogs may be environmental and seasonal, depending on the origin of the allergen. Environmental allergens may include pollens, grasses, seeds, pollution, pesticides, detergents, building materials, or certain textiles.

Determining the exact cause of an environmental allergen is costly and time-consuming. Close patient monitoring and an in-depth clinical history help to rule out specific allergens if an owner diligently monitors their pet. 

There are allergy tests available to identify allergens in pets. A vet draws a blood sample from your pet to perform the radioallergosorbent or RAST test. This test helps identify triggers of allergies. Owners may consider limiting their pet’s exposure to allergens or consider hyposensitization treatment. 

Intradermal testing (IDT) indirectly tests the reactivity of mast cells due to IgE. A vet needs to know the exact regional allergens to interpret an IDT accurately. The National Allergy Bureau, veterinary dermatologists, and veterinary schools in the area offer the best resources to obtain suggested regional allergens. 

Food Allergies 

Dogs suffering from food allergies develop symptoms like chronic vomiting, diarrhea, inflamed gums, swelling or redness of the ears, and weight loss. The allergen causing the issue ranges from grains to animal proteins such as chicken, beef, or milk. A diet trial is often the only way to rule out the inciting cause of allergies if owners decline allergy testing. 

Dog foods for dogs with skin allergies recommended by vets may be either a therapeutic food with a single novel protein or food with hydrolyzed protein. 

A novel protein diet describes food with a unique protein not commonly used in pet nutritional formulations. These proteins carry a lower risk of adverse reactions in hypersensitive dogs.

A hydrolyzed protein diet uses amino acids gently broken down into fragments to avoid immune system detection.

Atopic Dermatitis

Atopy is a diagnosis of exclusion when a pet is refractory to all other treatments. This condition frequently occurs in genetically predisposed individuals with inflamed and itchy skin diseases. 

Atopy is a painful and debilitating condition if left untreated, often resulting in significant deterioration of the pet’s quality of life.

Before a clinician considers atopy, a few basic steps are necessary to exclude other diagnoses.

Basic steps to ruling out the origin of allergies in an itchy dog:

  1. Flea bite allergy – ensure that the itchy pet, all the household pets, and the environment at home are free of fleas.
  2. Ectoparasites – mites cause severe itching, so ensure that pets are up to date with an external parasite control that is effective against mites. 
  3. Pyoderma and Malassezia – bacterial infections and yeast infections such as Staphylococcus pseudintermedius and Malassezia cause severe itching and may obscure allergy treatments if not cleared completely.
  4. Canine Adverse Food Reactions – strict dietary compliance is vital when treating a dog with suspected food allergies.

Clinical presentations of atopy vary due to genetic factors, lesion severity, secondary skin infections, and other similar diseases. The variation makes it very difficult for vets to quickly diagnose atopy without extensive testing and clinical trials with various diets and medications.

To diagnose atopy, clinicians need to rule out any other potential skin disorders similar to the symptoms of atopic dermatitis. Vets require a detailed clinical history and physical exam to determine if a patient has atopy. Clinicians may request diagnostic tests such as a complete blood count, biochemistry, and intradermal and allergen-specific IgE serum allergy testing. 

Itchy dog

Key Takeaways

Don’t let an allergic dog get under your skin. Owners that use quercetin for dogs with allergies often see great benefits when used in conjunction with bromelain and careful instructions from their veterinarians. 

Allergic dogs often present to vets with frustrated owners. Allergies affect not only a pet’s quality of life but their owner’s quality of life. Sleepless nights, expensive vet bills, and chronic medications often discourage pet owners. Allergies are challenging, but you are not alone. 

Trying to control a dog’s overreactive immune system poses multiple challenges. Determining the exact cause of allergies takes time, commitment, strict compliance, numerous vet visits, and high costs for diagnostic tests and trials. 

Holistic medications offer a great alternative to prescription medications when used in consultation with the attending vet. Good nutrition, a strong skin barrier, and proper grooming habits help to keep a pet’s skin happy and healthy.

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Dr. Kaylee Ferreira, a South African vet from Johannesburg, excels in diverse veterinary roles. Founder of Kubuntu Veterinary Services, she's a dedicated animal lover and adventurer.