Allergies in dogs

Allergies in dogs

Dogs, like humans, can also get allergies. It is often difficult to determine the cause of an allergic reaction in dogs.


An allergy is defined as excessive activity of the immune system. The allergen, a substance which is harmless in itself, triggers a strong immune response in the form of inflammation. In humans this can lead to hay fever and watery eyes, and can also cause itchiness, reddening of the skin and digestive problems depending on what part of the body is affected.


For dogs, the case is similar: contact with the allergen - whether in the air, through skin contact or in food - leads to a strong immunological defence reaction. In our four-legged friends it is predominantly the skin that is affected. Itchiness causes them to scratch themselves until the skin is raw or lick themselves until they are bald. Some dogs also develop chronic digestive problems which are manifested in the form of diarrhoea, vomiting, flatulence and loss of appetite. If the respiratory tract is affected, this causes a sniffling nose, watery eyes, coughs, and asthma.

Common allergies in dogs

In dogs the most common allergy is to flea saliva. Often just one flea bite is enough to cause itchiness in the animal for weeks. Other allergens to consider include pollen, grasses, house dust, mould spores, food and medication. In addition, there are contact allergies e.g. in areas with little fur coverage which come into contact with, for example, carpet, plastics or cleaning products.

Treating an allergy

The general approach to treating an allergy is for the dog to avoid the allergen in question. An exact diagnosis, however, is vital in this regard. It is often a difficult and protracted process to find out what allergens are causing the problem. The first step, moreover, is first of all to ensure that the problem actually does ensue from an allergy as many other conditions can cause similar symptoms. Unfortunately, there is no such thing as a simple and reliable allergy test. Very important is a thorough examination which will also rule out many other conditions. If the suspicion of an allergy is confirmed, systematic attempts should be made to detect the allergen triggering the reaction e.g. in the case of a flea saliva allergy, the flea bite or flea excrement. Pollen and grasses can also be tested using a skin test. If the allergen is from the food, a so-called elimination diet is the only way to ensure correct diagnosis.

The process of allergy treatmente

Patience is usually required: depending on the severity of the allergy it can sometimes take weeks until symptoms are alleviated and the diagnosis can be confirmed. As a dog owner never give up too quickly: in the case of particularly tricky food-related allergies, it can take up to 12 weeks before the dog responds to treatment. Once the allergen has been identified, however, the animal has good prospects of a full recovery if the dog follows a special diet in future to avoid the food-based allergen. In the case of grasses and pollens, subsequent attempts can be made to help the animal by implementing desensitisation measures. And flea bites can be prevented through the use of a flea control product from a vet.