Atopic Dermatitis in Dogs: Causes, Symptoms and Treatment

Bacterial diseases in dogs

Dog atopic dermatitis is also known as contact dermatitis and environmental allergy. It is a chronic inflammation of the skin (dermatitis), which is caused by contact with certain allergens (allergy-causing proteins). The allergic disease usually occurs at an early age, between about 8 months and 3 years.

Also Read: Arthritis in Dogs


In dogs, atopic dermatitis can be partly caused by food as well as by various environmental influences. Depending on the allergen that leads to the disease, there may be a seasonal problem (eg with grasses) or a problem throughout the year (eg feed allergies). The following allergens are among the most common causes of canine atopic dermatitis:

  • Grasses, pollen, and fungi
  • Parasites: fleas, dust mites
  • Feed

It is not yet fully explained why a dog reacts allergically to these allergens. However, it is believed that factors such as genes or too much hygiene play a major role. The latter is based on the fact that the immune system of affected dogs reacts to new and otherwise harmless environmental influences. At the center of the allergic reaction is always an allergen (protein), which causes a so-called immediate reaction upon contact. Certain cells of the immune system (T helper cells) produce more antibodies (immunoglobulin E, IgE). When these bind to the allergens, histamine is released en masse, causing allergic symptoms such as redness, itching, and swelling in the body. So it is a hypersensitivity reaction.

In addition to the actual allergic reaction, atopic dermatitis in dogs can be made worse by a bacterial secondary infection. Licking skin areas makes it easier for bacteria and fungi to penetrate the skin and can partly lead to a purulent course. Bacteria and fungi, in particular, play a role in the normal skin flora of the dog, such as streptococci or Malassezia.

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Canine Atopic Dermatitis: Symptoms

Dog atopic dermatitis can occur throughout the year or in certain seasons depending on the cause and normally progresses with spurts. The most affected areas of skin are the front legs (particularly between the toes), the tips of the ears and lips, the conjunctiva as well as the beginning of the neck, and the underside of the abdomen. Since the severity strongly depends on the severity of the allergic reaction and the way of contact, the affected skin barriers partly show different syndromes:

  • Itching: nibbling, licking, and scratching the affected areas on the body
  • Baldness (alopecia) and possibly skin lesions
  • Inflamed skin areas: redness, increased heat, pain, possible wound secretion
  • Conjunctivitis (conjunctivitis) and inflammation of the lips (cheilitis).
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The diagnosis of atopic dermatitis in dogs is based on the exclusionary diagnosis. In order to better define the causes of the allergy, the owner is first thoroughly questioned (anamnesis) by the vet. For example, if the symptoms mainly occur in the summer, this could be a sign of pollen-induced atopic dermatitis.

When the vet has experienced all the important information from the dog owner, the general clinical examination follows after the anamnesis. Parameters such as general well-being, body temperature, or respiration help to interpret the general well-being of the dog. In some cases, this is an important requirement for further diagnosis.

If the dog is in a good general condition, the specialized examination can take place after a general clinical examination. To distinguish a food-induced atopic dermatitis from one that originates from environmental influences, a so-called elimination diet can be introduced. Your dog has to forgo his known food for several weeks. If symptoms improve, this is an indication of an allergy caused by foods. However, to confirm the suspicion, the dog can be fed again with the old food. If he then shows allergic reactions again, it can be assumed that he has food-induced atopic dermatitis. However, if this test is negative, the vet can measure the level of immunoglobulin E in the blood or in the skin (intradermal test) to diagnose environment-dependent atopic dermatitis. However, healthy dogs also have IgE in their blood and skin, so the results of both tests are not always accurate.

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  • The treatment of atopic dermatitis in dogs focuses on the cause and severity of the disease:
  • Allergy avoidance: eg long-term selective feeding (eg commercial diet food or individually prepared food). Discover our range of dog food for skin diseases!
  • Medications for Allergic Reactions: Antihistamines
  • Treatment of the secondary infection: antibiotics or antimycotics
  • Treatment of the symptoms: anti-inflammatories (shampoos, tablets, ointments), glucocorticoids (cortisone) under veterinary supervision, atopic (deactivates immune cells), vitamin preparations, topical calcine-urine inhibitors (eg tacrolimus, anti-inflammatory, and immunosuppressive).

If the avoidance of allergens is not possible, desensitization can be done. This concerns allergen-specific immunotherapy (ASIT), in which the dog has injected individually produced allergens under the skin. A low dose is given at the start of treatment, which is increased to a lifetime maintenance dose over the course of treatment. If the dose is reduced or the treatment is stopped completely, in most cases a new deterioration occurs.

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Since the immune system has a very good memory, atopic dermatitis is an incurable disease. In order not to limit the quality of life of the dog, lifelong treatment and good cooperation between owner and veterinarian are very important.

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Allergies in most cases occur suddenly and without warning, so there is no effective way to prevent them. However, if the cause of the disease is already known, further jumps can be limited by the above treatment measures.


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