How Can You Tell If a Dog Has Allergies?

• Causes & Types
  • What causes allergies in dogs?
• Diagnosis & Treatment
  • How are dog allergies treated?

Allergies are actually pretty common in dogs. But since your dog can’t tell you when it's having an allergic reaction, it’s up to you to be able to spot the signs. Symptoms of allergies in dogs vary depending on the cause or type, but common signs may include:

• Constant biting, scratching, and licking of affected skin
• Redness, irritation, and inflammation of the skin
• Swelling of the throat, lips, face, eyelids, or earflaps
• Diarrhea
• Vomiting
• Sneezing
• Nasal discharge
• Recurrent ear and other infections

Since some allergy symptoms can be a sign of underlying medical condition, it is important to consult a veterinarian for an accurate diagnosis and appropriate treatment.

Skin allergies or allergic dermatitis

Skin allergies in dogs could be due to fleas (flea allergy dermatitis) or other environmental allergens. The dog may be allergic to flea saliva and keep scratching itself after getting flea bites. Itching most affects the ears, paws, and base of the tail. Their skin can become irritated, inflamed, red, and scabbed, with scabbed areas prone to infection. 

Food allergies

Dogs with food allergies also present with itching, most commonly in their ears and paws. The dog may also have facial swelling, hives, and gastrointestinal symptoms (vomiting or diarrhea).

Food sensitivity or intolerance differs from allergies. Allergic reactions are sudden and acute. Food sensitivity causes chronic gastrointestinal problems, chronic itching, skin and ear infections, and poor coat condition. 

Environmental allergens

Dogs can also be allergic to environmental or seasonal allergens, such as dust, mold, or pollen. The most common sign is itching in the ears and paws. Other areas that can get affected are their toes and the skin around their eyes, nose, and underarms.

Secondary infection

Dogs that have itching tend to constantly scratch, bite, or lick at the affected areas, which can result in open wounds. These open wounds have a high risk for secondary fungal and bacterial infections that may require treatment.

Anaphylaxis

Anaphylaxis is a severe, acute allergic reaction and can be fatal, requiring emergency medical care. Common causes of anaphylaxis may include bee stings, medications, certain foods, or vaccines. Though rare in dogs, anaphylactic reactions may present with hives or swelling of the throat, lips, face, eyelids or earflaps. If you notice any of these signs, your dog should be taken to the vet right away.

Your vet will perform a complete examination and may advise allergy testing or blood tests to diagnose complicated allergies or rule out other conditions that could be causing your dog’s symptoms. Some allergies are identified by avoiding exposure to the allergen in question, for example, using an elimination diet to identify food allergies.

The first line of treatment is to eliminate your dog’s exposure allergen as much as possible. However, this can be a challenge depending on the type of allergy and allergen. For example, eliminating fleas in all surrounding areas can be difficult. Food allergies and sensitivity, on the other hand, are easier to manage because they mainly involve a change in diet. 

Your vet may also prescribe medication to help manage itching, or antifungal/antibacterial treatment for infected wounds. In the case of anaphylaxis, emergency treatment at a veterinary hospital is necessary.