Common Allergy Symptoms in Dogs

Allergies are the most common cause of skin problems in dogs, often causing itching and skin irritation. Allergies in dogs can also affect the gastrointestinal system and the upper respiratory system. Dogs with allergies need prompt treatment to relieve uncomfortable symptoms. You can work closely with your veterinarian to develop the best allergy treatment plan for your dog.

Causes of Allergies in Dogs

An allergy occurs when the immune system overreacts to a particular substance called an allergen. The immune system identifies the allergen as a harmful substance and responds by producing antibodies to destroy the allergen.

Allergen particles may be inhaled, ingested, or come into contact with the skin. In dogs, most allergies lead to skin irritation and inflammation. Some dogs will experience upper respiratory symptoms. Allergy symptoms may include:

• Itching that causes frequent scratching, licking, and chewing of the skin
• Hives
• Skin redness or irritation
• Hot spots
• Hair loss
• Ear infections
• Facial swelling
  
• Sneezing
• Eye discharge or redness
• Vomiting
• Diarrhea

Airborne Allergies

Most of the allergens that affect dogs are in the air and environment. Airborne particles may contain pollen, dust mites, mold spores, and animal dander. These particles are inhaled or stay on the surface of the skin, triggering an allergic reaction. Most dogs will experience pruritus (itching) and irritation of the skin and ears that can lead to infection. Some inhaled allergens cause signs similar to hay fever in humans.

Flea Allergies

Dogs that react to fleas with intense itching are experiencing a reaction to flea saliva. The skin may become red and irritated and hair loss may occur. Not all dogs are allergic to flea bites. However, other skin reactions may be exacerbated by the presence of fleas.

Food Allergies

Food allergies are less common in dogs than airborne allergies. Dogs with food allergies are often sensitive to one or more of the proteins in their dog food. Most food allergies cause itching and irritation of the skin and ears similar to airborne allergies. Other dogs with food allergies experience vomiting and diarrhea.

Anaphylaxis

Some allergens cause a sudden and dangerous immune response called anaphylaxis or anaphylactic shock. This is a life-threatening emergency that requires immediate medical attention. Signs of anaphylaxis in dogs include a sudden onset of vomiting, diarrhea (often bloody), weakness, pale gums, or collapse. Most cases of anaphylaxis are caused by insect bites or stings. Though uncommon, vaccines can cause anaphylactic shock in dogs. Foods or medications may also cause anaphylactic reactions in some dogs.

Treatment and Prevention

There are several treatment options available for allergies in dogs. The first goal of treatment is to reduce the symptoms and give the dog some relief. Your vet may prescribe antihistamines, steroids, or other antipruritic drugs like Apoquel to reduce itching. Topical sprays, creams, or ointments may be used to reduce itching and inflammation on contact. Your vet may also recommend medicated baths to treat the skin. Antibiotics may be necessary to treat secondary infections.

Flea control should be used all year long to prevent flea allergy flare-ups and to keep flea bites from exacerbating other allergies.

Dogs with severe airborne allergies may benefit from immunotherapy. This is often done through a veterinary dermatologist. First, skin testing is performed to evaluate the reaction to tiny amounts of specific allergens. Then, a special injectable serum is developed especially for your dog. These injections are meant to desensitize the dog's immune system to the allergens over time. Immunotherapy can greatly reduce or eliminate allergies in some dogs.

If your dog has food allergies, your vet may recommend a food trial or elimination diet. Your dog will be placed on a strict special diet for about eight to 12 weeks. This diet may contain limited ingredients or hydrolyzed protein. The goal is to remove common food allergens and evaluate the dog's response. Some dogs need to remain on the special diet long term, but other dogs may be able to tolerate adding one new ingredient at a time.

You can't necessarily prevent allergies from occurring in your dog. However, early detection and treatment can keep skin problems from getting out of control. It's important to follow your vet's advice and communicate about any changes in your dog's health. For many dogs, allergies are a life-long issue that may come and go over time. Frequent and repeated treatments may be necessary to keep allergies under control.