Common Allergies In Dogs

Allergies In Dogs

Highlights: Common Allergies in Dogs and Their Treatments

  • Frequent Allergies:
    • Flea Saliva Allergy
    • Atopic Dermatitis (Environmentally triggered)
    • Food Allergies
  • Symptoms:
    • Common across all allergies include intense itching, gastrointestinal issues, and inflammation in areas such as paws and ears.
  • Diagnosis Challenges:
    • Diagnosing allergies in dogs is complex due to overlapping symptoms across different types of allergies and the potential for a dog to have multiple allergies simultaneously.
  • Flea Allergy Dermatitis:
    • Affects dogs of all breeds and ages after six months.
    • Symptoms triggered by flea saliva proteins, requiring consistent flea control and environmental cleaning for management.
  • Atopic Dermatitis:
    • Is genetically predisposed and affects certain breeds more commonly, including Terriers, Retrievers, and Bulldogs, among others.
    • Triggered by environmental allergens like pollen, dust, and mold.
    • Management includes avoiding allergens where possible and may involve immunotherapy.
  • Food Allergies:
    • No specific breed or age predisposition.
    • Diagnosed through exclusion diets and potentially managed by avoiding identified allergens or adopting a hydrolyzed protein diet.
  • Treatment Approaches:
    • Flea control for flea allergies.
    • Avoidance of known allergens for food allergies, with diets adapted to exclude specific allergens or incorporating hydrolyzed proteins.
    • Immunotherapy for atopic dermatitis, aiming to build tolerance to environmental allergens.
  • Emergent Solutions:
    • Insect-based proteins as a novel approach in the management and diagnosis of food allergies.
  • Importance of Veterinary Diagnosis:
    • Due to the complexity and similarity of symptoms, a thorough veterinary examination, including historical data and possibly intradermal or blood testing, is crucial for accurate diagnosis and treatment planning.

      Understanding and managing allergies in dogs necessitates a comprehensive approach involving identification, avoidance, and appropriate treatment of the underlying causes, with a significant reliance on veterinary guidance for the best outcomes.
      The first thing you think about when you see a dog scratching is parasites, but there are other reasons for itching and scratching in dogs, such as allergies. Allergies are quite common in dogs and the number of allergic reactions increases every day.

      Which allergies occur most often in dogs?

      The most common allergies in dogs are:

      • Allergy to flea saliva
      • Allergy to environmental factors, atopic dermatitis
      • Allergy to food

      All three types of allergies are more or less manifested in dogs by the same symptoms. It is often difficult to diagnose. There may also be several allergies at the same time.

      Allergy to flea saliva

      Flea allergy is not specific to a particular breed. Even more, dogs of both sexes are equally affected. It is usually caused by cat fleas, Ctenocephalides Felis, which are not specific to a host, but other flea species can also cause this allergy. Flea allergy can occur at any age, but not before the sixth month of life. Flea allergy is caused by the proteins in flea saliva. Through their bite, fleas not only suck blood from the dog but also inject flea saliva at the same time. This will be either an immediate reaction, type I reaction, through which the blood reacts within 30 minutes, or a delayed reaction, type IV reaction, through which the symptoms appear several hours up to 2 days after. Generally, dogs that do not have frequent contact with fleas are affected by allergies. Dogs that come into regular contact with fleas may develop a tolerance.


      Atopy is an allergy to environmental factors, that affects about 15% of dogs. Unlike flea allergy, some breeds are prone to atopy. These include:

      • Terrier
      • Golden Retriever
      • Labrador Retriever
      • Dalmatian
      • German Shepherd
      • Boxer
      • English Bulldog
      • English and Irish Setter
      • Shar Pei

      The disease usually occurs between the ages of one and three, and very rarely before a dog turns six months old or older. The condition of atopy is the dog’s predisposition to react strongly to an allergen. These dogs react to harmless substances in the environment, such as pollen, grass, household dust, mites, and mold by forming antibodies. This causes a massive secondary inflammatory reaction with tissue damage. Symptoms can be observed depending on the season, for example, allergy to grass blades. Allergens enter the body through the respiratory tract or through the skin.

      Allergy to food

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      There is no predisposition to food allergy depending on race or gender. Even more, it can appear at any age. In the case of a true food allergy, the dog needs to eat a certain type of food for a longer period of time before the reaction occurs. The healthy animal develops an immunological tolerance against the components in the food. However, if the protective function of the intestinal lining is reduced, allergens can pass the intestinal barrier and trigger an allergic reaction.

According to current knowledge, allergens in dogs are proteins or components of proteins of a certain size, contained in food. Therefore, each protein can lead to allergic reactions, and the likelihood increases with the frequency of consumption. The most common allergens are beef, milk and dairy products, eggs, cereals, and chicken. Food allergies can have immediate and late reactions, or possibly a combination of both. So, symptoms can occur within 30 minutes, a few hours, or even days and weeks after ingesting the allergen.

Symptoms of allergies in dogs

Dog SneezingSigns of an allergy:

  • Itching: The dog is constantly scratching
  • Gastrointestinal symptoms: The dog has digestive problems, such as vomiting or abdominal pain
  • Inflammation: Inflammation occurs in the paws and ears

The main symptom of all allergies is itching. In the case of flea allergies, this mainly affects the back half of the body, back, legs, tail base, back legs, and stomach. The dog scratches and rubs itself in these places, resulting in a so-called “Hot Spot”, an inflamed and purulent wound caused by strong itching. These areas are often full of bacteria and fungi, which accentuate the itching sensation.

The distribution of itching is quite similar in the case of atopy and food allergy, which makes it difficult to distinguish between the two. Itching occurs in the area of the head, paws, underarm, abdomen, inside the thighs, and ears. The paws, the area between the fingers and the lower part of the paw becomes inflamed. Inflammation of the external auditory canal may occur in the ears. Bacteria and fungi usually form on the affected skin, causing an infection, secondary infection, and additional itching. In the case of food allergy, additional gastrointestinal symptoms may occur, such as vomiting, diarrhea, bloating, severe abdominal pain, and deformed feces.

Diagnosis of allergies

How can a veterinarian identify allergies in a dog?

  • Diagnosis by exclusion
  • Intradermal test
  • Blood tests
  • Diet by exclusion

Since the symptoms of individual allergies are very similar, diagnosing them is a real challenge. Even more, a dog can suffer from several allergies at the same time. Unfortunately, there are no easy and reliable tests that can tell the difference between allergies. Thus, allergy is identified by exclusion diagnosis. A detailed history as well as symptoms can give you some clues.

The following should be communicated to the veterinarian during the anamnesis:

  • Breed
  • Sex
  • Age
  • Age at the onset of symptoms
  • Localization of itching or skin symptoms
  • The presence of similar symptoms in the siblings or parents of the dog
  • The time when the symptoms appeared

Allergy to flea saliva

Even if the symptoms do not indicate an allergy to flea saliva, do not exclude it from the start. The veterinarian may examine the dog with a special brush to observe fleas or flea droppings. If he finds one of them, they confirm his suspicion. An intradermal test can also be used for diagnosis. In this test, flea allergens and control substances are injected into the skin on the chest and allergic reactions are monitored at 15-30 minutes, then at 4 to 6, and 24 to 48 hours. There are also blood tests to diagnose flea allergy, but they only provide information for type I reactions. Diagnostic therapy can also be done. By means of this, both the dog and the other animals in the house are treated with flea preparations. A flea allergy is possible if the therapy is successful.

Food allergy

To confirm or exclude a food allergy dermatologists recommend only a diet by elimination or exclusion. Through this diet, the dog should receive a source of protein and carbohydrates, which has not been received until now for a minimum of eight weeks. Since he has not had contact with these substances, he cannot react to them. Don’t give your dog anything else during this diet, and snacks and rewards must be made from the recommended diet ingredients.

Dermatologists recommend a diet with home-cooked food. If the owner does not have time to prepare the dog’s food, there are diets with hydrolyzed protein. In this case, the ingredients are so small that the body cannot recognize them as allergens. Even more, you can give it varieties of monoproteins. Symptoms should improve significantly during the diet. Once the symptoms have receded, a “challenge” is made by giving the food before the diet. If symptoms recur, this is evidence of food allergy.

Atopy in dogs

Diagnosis of atopy is done clinically and by excluding other diseases. Diagnosis can only be made after clarifying certain aspects. It must fit the symptoms, age, distribution of itching, and other points. Other possible causes of itching are also carefully excluded. Your veterinarian can now perform specific tests to identify the allergens that triggered the reaction. The most appropriate method is the intradermal test, by which allergens are injected into the skin, and reactions to them are observed. The test should always be done by an experienced dermatologist. It is also possible to diagnose with blood tests, but they can also show false positive reactions.

Treatment in allergies

The best way to treat allergies in dogs is by avoiding the onset of allergens, but this can be difficult depending on the allergy. The treatment of flea allergy consists of the consistent parasite control procedure of the dog. Be sure to treat the other animals in the house with parasite control medication, so that the allergic dog does not have contact with fleas. It is necessary to treat and clean the environment carefully, especially in allergic dogs that are infested with fleas. If they are scratching, you can treat them with the right preparations to avoid secondary infections.

Identifying the allergen that caused the reaction, for example, beef, helps a lot with food allergies, because the dog can continue to eat normally by avoiding the allergen. If you can’t find the allergen or your dog reacts to several types of protein, you can adopt a diet based on hydrolyzed protein. Recently a type of insect food has emerged as a source of protein, which is a new approach in the process of diagnosis and treatment. Itching is harder to treat, but it is possible with preparations such as glucocorticoids or antihistamines. These medicines are not as effective for food allergies as they are for flea allergies or atopy.

How is atopy treated?

Treating atopy is a challenge because it is almost impossible to avoid the allergen, which caused it. If itching is limited to a few months a year, you can give your dog anti-scratching medication during this time. If the dog has itching for a longer period of time, hypersensitivity is recommended. This is immunotherapy. Through this process, allergens are administered to which the dog reacts in high concentrations. The goal is to stimulate the dog’s immune system and achieve tolerance to allergens.

Unfortunately, this therapy does not always have the desired effect. You may need medications to reduce itchings, such as cortisone, antihistamines, cyclosporine, essential fatty acids, or oclacitinib. A new treatment for itching caused by atopy, a preparation with monoclonal antibodies, appeared on the market. These antibodies absorb the substance responsible for itching and are metabolized as if they were the body’s own proteins. This form of treatment has been very effective so far and is tolerated quite well.

Prevention of allergies in dogs

Preventing an allergy is difficult because it takes many factors to develop an allergy in dogs. If a dog allergy is already known, others may follow. To avoid flea allergy, be sure to constantly treat the dog against fleas and parasites. It is also recommended to give your dog a varied diet with several sources of protein. Avoid exotic proteins, as they can be useful as the basis of a diet in case of allergy. Since atopy is a hereditary form of allergy, it is recommended not to let mate dogs with an allergic medical history.

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