Allergies can be seasonal in pets, just like people. When this is the case, we know it is an environmental allergy. Dogs' allergies typically get worse with age, and may progress from seasonal to year-round.
Allergies are the result of an overactive immune system, which is responding to things which are normal in the environment. This response leads to inflammation, which causes the signs mentioned above. Because this is an immune system related issue, it can be genetic, and be passed on from parents to offspring. We also see an increased incidence of allergies in certain breeds, typically those breeds that are or have been quite popular and were bred in great numbers at the height of popularity. Golden Retrievers are one of the breeds with an increased rate of allergies.
Sometimes other health problems can look like allergies. For instance, dogs with hypothyroidism are much more likely to display signs that appear allergy related, because of the effects of thyroid hormone on skin. Correcting the underlying problem and then re-evaluating the allergies is the best way to go. This is why a thorough checkover is important before a diagnosis can be made.
Pets can also have food allergies, which are a bit harder to pinpoint. Oftentimes this will present as vomiting frequently, a poor hair coat, diarrhea or soft stools, or maybe just a thin animal. Sometimes owners will change the food and the signs will stop for awhile, and then start again after the pet has been on the new food for some time.
In the past few years there have been great advances in the field of allergy testing. Now we can send in a blood sample and get a pretty good idea of what your pet is allergic to. Especially with food allergies, this test is quite accurate. Once we have the results from the allergy test, we can proceed in a couple different ways. If it is an environmental allergy, hyposensitization therapy is answer. This is a form of treatment where a solution is made of the allergens your pet reacted to, and it is given as an injection over a period of time. Typically at the start of treatment the injections are more frequent, and then taper off somewhat as the treatment continues. Most animals respond very well to this treatment, and within a couple months the signs of allergies lessen and disappear. If the allergy test results show a food allergy, we have a different route of treatment. Depending on what exactly your pet is allergic to, there are several different foods available. There are limited ingredient foods, like duck and potato or venison and pea, where the idea is to avoid the specific ingredients your pet has problems with. And then there are some animals that are allergic to most ingredients and need a food where all the proteins are broken down to such a small size that the body cannot recognize them. These are called hydrolized protein diets, and are not allergenic at all.
Allergies can take many different forms and your pet may give you a variety of clues. If you have hayfever, keep an eye on your pet for some of these signs. If you see them, it is probably time for a visit to the vet!
Interestingly, when we used to do skin testing, about 1/3 of dogs were allergic to human dander. Hmmm...