The Most Common Allergies in Dogs

Our four-legged friends can also suffer from hay fever or food allergies. Read here about the symptoms that trigger allergies in dogs and how to treat them.

Allergies – the Immune System is Going Crazy

A characteristic of allergies is that the immune system is directed against harmless substances from the environment and fights them. In dogs, allergies mainly affect the skin: They are among the most common skin diseases in four-legged friends. For example, they can lead to “hot spots” – localized areas where the dog scratches itself severely. The stomach and intestines as well as the respiratory tract can also be affected.

Many factors are involved in the development of allergies. Some breeds are more prone to allergic reactions than others – this includes the Cocker Spaniel, for example. The susceptibility to allergies in these breeds lies in their genes. External influences can also play a role: Frequent bathing with shampoo or prolonged flea infestation weakens the skin barrier. Gastrointestinal disease or the administration of antibiotics make the gastrointestinal mucous membrane more sensitive and therefore more susceptible to allergies. Here is an overview of the most common allergies in dogs:

Feed Allergies

Allergic to what?

Beef or wheat – the dog is allergic to one or more of the ingredients in the food. Snacks or chews can also trigger an allergy.

Symptoms and Diagnosis

A feed allergy can affect the skin or the gastrointestinal tract. Redness, itching, or crusts can appear on the skin, especially in the head area and on the legs. The dog scratches itself, which can lead to secondary infections. Gastrointestinal symptoms such as diarrhea, mushy or slimy feces are less common. Food that is incompatible or irritates the stomach can lead to symptoms similar to those of an allergy. In practice, these differences are less important because the therapy is the same.


The classic remedy when a feed allergy is suspected is an exclusion diet. This is how the vet can find out what the dog is reacting to. The dog receives a special food that consists of an animal protein source that the four-legged friend has not yet got to know. For example horse and goat meat or food made from insects. The feed must not contain any known animal proteins such as chicken or beef. Treats must also meet this requirement. Gastrointestinal problems improve after just a week. Patience is required when it comes to the skin: Symptoms improve after six to twelve weeks. Only then can the food offer be expanded after consulting the veterinarian.

Flea Allergic Dermatitis

Allergic to what?

With a flea allergy, the dog is allergic to the bites of the fleas. Other insects can also trigger a similar skin reaction.

Symptoms and Diagnosis

As with many allergies, itching and reddened areas occur. The skin becomes inflamed. Hair loss and bloodred crusts, especially on the back of the body, can be signs of a flea allergy. If combined with these symptoms, fleas or flea droppings are found on the animal, the diagnosis of “flea allergy” is obvious.


With consistent flea treatment and subsequent prophylaxis, owners can protect the dogs from flea bites. The inflammation can be relieved with special ointments.

Environmental Allergies

Allergic to what?

Seasonally for pollen or all year round for dust mites or molds.

Symptoms and Diagnosis

The most common symptoms of environmental allergies include itching and secondary symptoms caused by scratching. The head and extremities, including the armpits, are mostly affected. Fungal or bacterial skin infections can occur. Untreated animals smell strong after a while, have bald spots or spots. Light-colored dogs can develop a brown discoloration from licking more often. When inhaling the allergens, the mucous membranes of the airways can swell – the dog breathes whistling.

In severe cases, it can lead to shortness of breath and thus to life-threatening.

Symptoms of an environmental allergy are less common than in humans. The veterinarian makes the diagnosis after excluding other diseases. A puncture test or examining respiratory secretions can also help.


Owners should try to reduce or eliminate the allergen in question. Of course, this is not completely possible with environmental allergies. But tips for allergy sufferers such as “washing the blankets at 60 degrees”, “pollen protection fleece on the windows” can also help four-legged friends. Depending on the symptoms, the veterinarian may recommend symptomatic therapy. However, antihistamines only work in every third dog. Cortisone has side effects.

In the case of pollen allergies, however, it can help in the short term. Just like immunotherapy. The four-legged friend regularly receives small amounts of the respective allergen by means of injections. The goal is to get used to it. Symptoms improve in around two-thirds of affected dogs. Disadvantage: lifelong treatment is required.

Contact Allergy in Dogs

Allergic to what?

A new detergent or collar, toys, or dishes – contact allergies can occur as a reaction to (almost) anything.

Symptoms and Diagnosis

Affected animals show symptoms after contact with the triggering substance or object. Symptoms include itching and redness, medium-term inflammation. A look at the surroundings is required: a reddened snout after eating can indicate that the dog is allergic to the metal of the bowl. If the skin of the abdomen is reddened, the new detergent that was used to wash the blanket could be the trigger. The diagnosis of contact allergy in dogs results from careful observation on the part of the owner in combination with the exclusion of other diseases.


The best therapy is to avoid the triggering substances. The inflammation or fungal infections that occur in dogs in combination with a contact allergy are a challenge. Several allergies are possible at the same time, which makes therapy more difficult. It takes weeks before the success of the therapy is visible. Patience is required!

Allergy to Medication

Allergic to what?

The active ingredients of some medications can cause allergic reactions. It can be triggered by injections, tablets, ointments, or care products.

Symptoms and Diagnosis

If the reaction occurs immediately after the drug is administered, there is an obvious connection. This is easy if the dog reacts to an ointment in a locally limited manner with severe reddening and itching. On the other hand, it is trickier if the dog has diarrhea or vomiting hours after a drug. The symptoms of the disease often make it difficult to diagnose an allergy. It is therefore important to notify the veterinarian of any noticeable changes after the administration of medication.


In the case of a drug allergy, it is important to consistently avoid the triggering agents. The veterinarian decides on a replacement medication.

Tips: Prevent and Fight Allergies in Dogs

With many allergies, the following applies: only perseverance leads to success! Meanwhile, treating the symptoms is important. Skin discomfort can be alleviated with antibacterial, antiseptic shampoos. Ointments or creams, for example with cortisone, can help the dog to feel good again in his skin. It is important to follow the advice of the veterinarian and not to experiment independently. Because with the wrong means, the skin barrier can be weakened and thus more vulnerable. It may be necessary to combine different therapies, and not only if there are several allergies occurring at the same time. The following tips also help to prevent and combat allergies:

  • If necessary, protect the dog from fleas and other parasites.
  • Make sure you have high-quality food.
  • Essential fatty acids, for example from linseed oil, support the skin.
  • Help your dog if he is constantly stressed. For example with a dog trainer or animal psychologist.
  • See the vet if you have skin problems.

Some skin or gastrointestinal disorders have symptoms similar to allergies.

These include mite infestation, fungal infections, or giardia in dogs. If you suspect an allergy, you should always see a veterinarian with your dog.

Alice White

Written by Alice White

Alice White, a devoted pet lover and writer, has turned her boundless affection for animals into a fulfilling career. Originally dreaming of wildlife, her limited scientific background led her to specialize in animal literature. Now she happily spends her days researching and writing about various creatures, living her dream.

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