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Allergic cross-reactivity 

Allergic cross-reactivity 

Synne Hemsen Berg

Allergic cross-reactivity occurs when a dog is allergic to food and something in the environment, often protein and pollen. Approximately 15-20% of dogs develop allergies over their lifetime, most often before turning 3 years old. An allergic reaction is an immune response where your dog’s immune system has an inappropriate reaction to ingredients/substances in their diet and/or environment. The most common allergens are:

  • Pollen from grass, trees, weeds
  • Dust mites
  • Chicken
  • Beef
  • Eggs
  • Mould spores
  • Fleas
Allergic cross-reactivity

What is allergic cross-reactivity?

Cross-reactivity is an allergic reaction that happens when your dog’s body identifies and attacks proteins from two different sources, typically pollen and food. Most commonly an allergic cross-reactivity occurs between food and pollen. 

An example of cross-reactivity is and allergy to rice and grass. Dogs with an allergy to grass pollen may be allergic to rice, as rice also belongs to the grass family. This was the case with our dog Nala. What can be tricky is that many allergy-specific/prescription diets for dogs use rice. Some cross-reactivities can occur between:

  • Grass pollen and rice. Other common cross-reactivities with rice include wheat, maize, spelt, carrots, tomatoes, lettuce, asparagus, peaches, citrus fruits, and peanuts.
  • Apple and birch pollen.
  • Birch pollen and potato.
  • Dust mites and wheat. This is not actually a cross-reactivity, but rather because mites may have infected the wheat. 
  • Peanut allergy can also create reactions to soy, peas, lentils and beans.
Allergic cross-reactivity

Symptoms of cross-reactivity

The symptoms of environmental allergies, food allergies and cross allergies are very similar. Therefore, it may take some time and various processes to determine what your dog reacts to. One sign of a possible cross-allergy is if the dog has a food allergy and it eats allergy-friendly food but the symptoms of allergy do not go away. Then it is likely that the dog reacts to something in the environment as well. Common symptoms of both food and environmental allergies include:

  • Itching
  • Licking
  • Hives
  • Recurring infections in the ears, eyes and skin
  • Red and irritated skin
  • Runny nose
  • Sneezing
  • Chewing paws
  • Vomiting

Diagnosing cross-reactivity

Diagnosing food and environmental allergies requires different steps. In order to determine if your dog has environmental allergies, your vet will do blood tests. Food allergies can also be determined by blood tests, however, these are not as reliable. Therefore doing an elimination diet is recommended.

It can be useful to create a diary to document symptoms when they are most troublesome and determine a likely allergen based on this. For example, if your dog displays allergy symptoms after playing on the lawn it may be due to a grass allergy. If they get itchy after being wrapped in a blanket, then dust mites are the likely culprit. 

Treating allergies

The best treatment for allergies is to avoid the substances your dog is allergic to. If your dog suffers from allergic cross-reactivity, you will need to do a combination of allergy-friendly food and medical treatments to manage both the food- and environmental allergies.

Allergic cross-reactivity

Treatments for environmental allergies include:

  • Allergy vaccines: This is an effective, but costly treatment. The treatment takes up to 2 years and includes giving your dog a monthly injection of the allergy vaccine. 
  • Washing your dog: Washing your dog after they have been in contact with an allergen will help reduce the allergic reaction as you remove the allergen. Make sure you also wash their paws as well as the fur. Use dog shampoo with the correct pH level. You can use diluted apple cider vinegar on a clean cloth as opposed to shampoo. Be mindful that excessive washing and damp skin may cause irritation and itching. 
  • Removing allergens: Remove allergens from their environment if possible. If your dog is allergic to grass, keep the grass short and try to keep your dog off the lawn as much as possible. 

Read more about environmental allergies in our blog

Treatment for food allergies

  • Allergy-friendly dog food that is void of any of your dog’s allergens.
  • Avoiding giving your dog treats and tidbits containing the allergen.

Read more about food allergies in our blog

Treatments for both food and environmental allergies

  • Cytopoint: This is an injection you can give your dog to reduce the symptoms of allergies. This will, however, not treat the allergy but is a more cost-effective way of dealing with environmental allergies. This treatment currently has the least side effects compared to other treatments like cortisone and apoquel. 
  • Omega 3, probiotics, coconut oil, quercetin and turmeric: these supplements will not treat allergies, but might help reduce inflammation. Omega 3 also contributes to skin health, which is important to reduce itching. 
  • Oral medication such as cortisone, apoquel and antihistamine.

Speak to your veterinarian to find a treatment that best suits your lifestyle and your dog. Allergies can be a complicated issue to treat, and cross-reactivity further complicates this. It is therefore important to have the patience to find a long-term solution that suits you and gives your dog the best quality of life possible.