Dog Allergy Symptoms
While not usually life-threatening, allergies in dogs do cause discomfort. Most symptoms are associated with dermatologic problems, but some can also lead to some dogs' chronic respiratory issues if untreated for long periods of time. Sometimes, an owner will bring their dog to a veterinary appointment, suspecting a serious medical condition, and end up finding out that their canine companion has an allergy.
Here are some allergy symptoms commonly found in dogs:
- Excessive licking
- Compulsive scratching
- Periodic chewing on the same or different body parts or areas
- Regularly rubbing body or body parts against the ground, walls, furniture, etc.
- Frequent sneezing and/or wheezing
- Skin irritation/fur loss
Most allergies develop in the second year of life for dogs. In the first year, the dog will be exposed to many types of allergens, primarily through contact with the skin. A smaller number of allergies may be caused by food (usually the protein source) and inhalant (things they breathe in that are in the air). In the second year of life, the dog's immune system will overreact to the antigen(s), causing a release of immune cells, which release inflammatory substances (such as histamine), leading to symptoms of itching. Rarely is a dog allergic to just one thing. Most allergic dogs are born with a less-than-optimal skin barrier, allowing antigens to enter the skin more easily. Dogs that suffer from allergies have abnormal skin and a less than optimal immune response, which allows for secondary infections to occur. Typically, dogs do not suffer from a single allergy; rather, dogs with sensitivities to allergens have a host of issues. You must understand that dog allergies are due to a complex set of issues that change as the dog's environment changes.
Because these symptoms can have several possible causes, we recommend making a veterinary appointment immediately if you notice your dog exhibiting any of the symptoms mentioned above. Early diagnosis and treatment of dog allergies not only increases the likelihood of your dog's treatment being successful but also may be less expensive than delaying treatment. The longer you wait, the more your dog suffers, and the more severe the secondary infections can become.
Dog Allergy Testing
The first step in determining the cause of your dog's symptoms is a thorough exam by your veterinarian. In addition to looking for external skin parasites, such as fleas and mites, your veterinarian will want to do some diagnostics to help him, or her determine what types of infections may be present. After diagnosing and treating for external parasites and infections, your veterinarian may want to discuss allergy testing. Once your veterinarian believes that allergies are the root cause of skin irritation/infection and discomfort, then he or she may recommend testing for specific allergens. There are many things to test to determine what may be causing your dog's allergies. Dog allergens fall into the following groups:
- Contact allergy - including many kinds of grass and plants, dust mites, and molds
- Flea allergies - many dogs are highly allergic to flea bites
- Food allergies - including different types of proteins
- Inhalant allergy (Atopy) - allergens that are inhaled
Contact allergens, such as flea, food, and dust/pollen, are by far the most common cause of allergies in dogs. These allergens can cause an allergic reaction in the body, focused largely on and within the epidermis, causing severe irritation. The result is a dog scratching itself to the point that skin infections and injuries can occur.
There Are Two Main Types of Dog Allergy Testing
Blood Testing and Intradermal Skin Testing. Each type of canine allergy testing is administered differently and has specific benefits and drawbacks. However, the following points hold true for both types of dog allergy testing:
- It is best to perform these tests during the season(s) when the allergy is the worst and therefore most likely to generate an accurate result.
- Testing should come after examination for other potential causes and irritators, including:
- Fungal or yeast infections of the skin (common secondary invaders)
- Chronic bacterial infections (common secondary invaders)
A veterinarian might also order a 12-week hypoallergenic diet to rule out a food allergy. Food allergies are difficult to detect using either dog allergy testing method, and therefore should be determined through dietary manipulation. Once all of these possibilities are ruled out, the veterinarian will order either a blood or skin test to determine the presence of dog allergies.
What Causes a Dog to Develop Allergies?
Think of a dog's skin like saran wrap. It covers and protects the dog. However, dogs with allergies are born with abnormal skin (like holes in the saran wrap). These abnormalities in the skin allow for the allergens, which are normal in all environments, to enter through the skin layer and set off an allergic response that causes itching and redness. It is important to understand that dogs who suffer from contact allergies do not have normal skin. Additionally, these dogs do not have a healthy immune response.
In addition, this inflammation in the skin will change the health of the skin and allow for secondary invaders such as bacteria and yeast to enter the dog's system. Many of these dogs have a less-than-optimal local immune response to these secondary invaders, making them more susceptible to yeast and bacterial infections. Yeast and bacteria are always present in low numbers on every dog's skin. Unfortunately for dogs with allergies, their skin and immune response are inadequate to fight off these secondary invaders.
Blood Allergy Testing
Blood allergy testing is the most common form of allergy testing because it is convenient and easy to do. A small sample of the dog's blood is drawn and analyzed to perform a blood allergy test. It is then tested for a reaction to a vast array of geographically appropriate allergens, including:
Blood allergy tests can also determine food allergies as well as allergic reactions to materials like cotton or nylon. Blood tests are much less invasive and time-consuming than skin allergy tests, and they are the most commonly used dog allergy test.
Skin Allergy Testing
Skin allergy testing for dogs is another form of allergy testing used by veterinarians and veterinary dermatologists today. Skin allergy testing is more invasive than blood allergy testing because it requires sedation due to the length of time the patient needs to remain still. To perform skin allergy testing for dogs:
- The patient is sedated
- The patient is placed on his or her side
- A small area on the patient's side is shaved
- Small needles inject tiny amounts of each test allergen just under the dog’s skin in a specific pattern and order. If the dog shows a small raised reaction, the allergen causing it can be identified.
After a period of time (usually a few hours), the shaved area is examined to determine which allergens elicited a reaction. Based on what the pattern indicates, a veterinarian and/or veterinary dermatologist can prescribe the most effective treatment protocol. Skin allergy testing for dogs has been estimated to be upwards of 75% accurate in determining the presence of dog allergies. However, skin allergy tests can be inaccurate if patients have received antihistamines or steroids in the months leading up to testing. Your veterinarian can help determine if skin allergy testing is appropriate and will yield accurate results for your canine friend.
Treating Allergies in Dogs
It is helpful to understand that allergies cannot be cured, but they can be successfully treated. There are many types of treatments, which include a combination of oral medication, bathing, topical therapy, and even injectable antigen therapy.
Prescribing the correct allergy medicine for dogs depends largely on the dog's symptoms, the severity of the symptoms, and preexisting medical conditions. Allergy medicines for dogs may be based on one or more of the following types of therapies:
- Anti-inflammatory therapy: Treats dog allergies with anti-inflammatory drugs such as corticosteroids or antihistamines that quickly block the allergic reaction in most cases.
- Immune modulators: These modify and reduce the dog's immune response to reduce the amount of itching which occurs from exposure to the antigens.
- Food and Dietary supplements: These include the use of protein-select diets and the supplementation of fatty acids. Some dogs have allergies just to food, and some may have a food allergy and/or contact allergies. The use of Omega three fatty acids can help improve the dog’s response to steroids and antihistamines in some cases.
- Antipruritic therapy (anti-itch): These include antihistamines, corticosteroids, and a new medication known as Apoquel, which specifically targets the itch response by blocking the substances in the body that cause itching.
- Shampoo therapy: Bathing can help remove the antigens the dog has been exposed to and remove dead skin cells and help treat secondary infections such as yeast and bacteria. Some therapeutic shampoos contain anti-inflammatory ingredients that may further benefit your dog.
- Hyposensitization therapy: If the specific offending allergens are identified by allergy testing, allergy shots can be given to the dog. This form of allergy medicine for dogs consists of weekly injections of very small amounts of an antigen. Repeated dosing helps reprogram or desensitize the dog’s immune system. Approximately 50% of treated dogs will see significant improvement in their clinical signs, while approximately 25% more will see a decrease in the amount or frequency of anti-inflammatory therapy.
To learn which allergy medicine and dog allergy treatment methods will work best for your canine friend, schedule an appointment with your veterinarian today. Every allergy case is different and must all be approached on a case-by-case basis.
Choosing the Best Dog Food for Allergies
Some dogs suffer from food allergies. The only way to determine food allergies is to do an elimination diet, where we change your dog's diet to a limited list of ingredients that contain no known allergens. These can be home-cooked or commercial diets (prescription) specifically made for dogs with food allergies.
We can help determine whether or not your dog has a food allergy by prescribing three possible diets:
- Limited ingredient diet: We limit the ingredients of your dog's diet to pin down the specific allergen causing your dog's reactions
- Novel ingredient diet: We introduce ingredients your dog has not been exposed to and are therefore less likely to be causing the reactions
- Prescription diet: We prescribe a kibble-based or ingredient-specific diet that is designed to contain hypoallergenic ingredients
It's important to remember that only about 10% of all dog allergies are food-based. Also, it is important to determine which food allergies your dog has. Schedule an allergy testing appointment and allow us to help your dog live a more comfortable life.