This is an excellent articles on how insect bites lead to allergies in pets.
Scientists also know that the flea, tick, & mite- type insects can transfer proteins in their saliva that are identical to proteins in beef and Pork. This is how a single allergy to biting insects can develop into a allergy reaction to food. Called Tick-food cross reaction allergy.
So what can be done to prevent food -insect cross reaction allergy? Thorough cooking (at minimum 30 minutes at low boil in water until the meat falls to pieces) is usually enough to breakdown the proteins. Commercial foods and treats are usually not cooked long enough to breakdown the proteins so many hypoallergenic foods fail. In humans this phenomenon is called “tick-food allergy cross reaction”, and cross reactions can also happen with many pollens called pollen-food cross reaction or Oral Allergy Syndrome.
This explains why homemade pet-foods, and a few of the freeze- dried, pressure treated pet-foods can extremely helpful to reduce allergy symptoms.
Anti-inflammatory supplements have also been shown to be very effective. High quality, fish oil with omega 3 fats being the best of all these products. This is the one time I recommend buying fish oil from your local vet. The prescription form of fish- omega 3 FA are filtered, concentrated which removes water, unneeded non-omega 3 fats and both heavy metals like mercury and other chemical contaminates. I have done numerous price comparisons, based on the effective dose of Fish-Omega FA (mgs) and found that the cost per pet is the same as over-the-counter brands.
Most veterinarians can/will sell these products without an appointment because of overwhelming science that shows how high quality fish oil prevents most diseases including teeth & gum disease.
Note to remember: Flax seed or borage oil are not effective in dogs nor cats. Carnivores lack the liver enzymes that convert vegetable Omega 3 fats into a form our bodies use to suppress inflammation. You are just getting expensive poop. These seeds or oils are added in tiny amounts to pet foods and treats to sell more product to health aware consumers.