What Causes Allergies in Dogs?

Symptoms, Causes, and Treatments

First off, what is an allergy? An allergy is an exaggerated immune response or reaction to substances that are generally not considered harmful. Atopy or atopic dermatitis is itchy skin that is caused by an allergic response to an inhaled environmental allergen.


Symptoms of Allergies in Dogs

Everyone wants to make sure their four-legged best friends are feeling the best they possibly can at all times. If you notice your dog starts to show any of the following behaviors, you may want to consult your veterinarian to ensure your dog is not suffering from an allergy.

  • Excessive licking including of the paws
  • Itching and scratching the affected areas of the skin
  • Chewing on affected skin areas
  • Hair loss or red irritated skin
  • Recurrent ear and/or skin infections
  • Swelling of the face or ears
  • Sneezing and/or itchy, watery eyes
  • Hives
  • Swelling of the mouth, throat, or eyes
  • Scooting the rear end on the floor 

The most common areas of skin affected will be; the face, ears, paws, the base of the tail, and abdomen. The symptoms of allergies may vary depending on the cause.

Causes of Allergies in Dogs

Common causes of allergies in dogs include food, flea bites, and inhalants. Allergy symptoms in pets develop when their immune systems begin to recognize certain substances (or allergens) as unsafe. Pets can be allergic to anything including environmental factors, household items, and food substances!

Flea Allergy Dermatitis

Flea allergy dermatitis is an allergic reaction to fleabites. This makes affected dogs itchy, usually at the base of the tail. Their skin may become red, inflamed, and scabbed. You may also notice flea dirt, or even see the fleas themselves.

Food Allergies

Food allergies and sensitivities can cause itchy skin and may be accompanied by gastrointestinal symptoms. The most common places dogs with food allergies itch are their ears and paws.

Environmental Allergies

Environmental allergies can be divided into indoor or outdoor allergies and include allergens such as dust, pollen, and mold. These allergens, along with others can cause atopic allergic reactions or atopic dermatitis. Typically, these allergies are seasonal, so your dog may only display symptoms during certain times of the year. The most commonly affected areas are the paws, ears, underarms, eyes, between the toes, and abdomen. 

Diagnosing Allergies in Dogs

Much like with humans, it can be a complicated task to determine what specific substance your dog is allergic to. Your veterinarian may first want to confirm that your dog’s symptoms are not caused by any other health conditions.

After ruling out other possibilities, if your veterinarian feels that an allergy is the cause of your dog’s symptoms, they may suggest an allergy test to determine the allergen your dog has a reaction to. Food allergies are oftentimes diagnoses using an elimination diet method. Flea allergy dermatitis is usually easier to diagnose than other allergies as it is often diagnosed by identifying fleas on your dog’s body and applying a product that kills fleas before they can bite. 

Treatment of Dog Allergies

The most effective way to treat an allergy is to avoid or remove the allergen that causes an allergic response in your dog, however this can be difficult. Treatment methods will differ depending on the type of allergy your dog has.

Medications for Treating Dog Allergies

Your veterinarian may recommend either prescription or over-the-counter medications for your pet's allergies. Over the counter allergy relief may include supplements and anti-histamines. Prescription medications may include medications to suppress the immune system, anti-inflammatories (including steroids), and possibly antibiotics for infections caused by damage to the skin. Topical options may include medicated shampoos or sprays to help with the affected areas of the skin.