Allergies in Dogs

Allergies are among the most difficult conditions to diagnose and treat. Understanding how allergies occur and why is the first step to treating a pet's allergies.

Allergies can affect dogs in a wide variety of ways. The allergen or trigger of the dog’s allergic reaction can be difficult to identify and the body’s response can vary dramatically – from dry, flaky skin, to itching, to welts and bumps on the skin, to facial swelling and vomiting, just to name a few.

Pet allergies are also difficult to identify and treat since each dog’s body reacts differently to various treatments, so there is often a great deal of trial and error required when it comes to the treatment of pet allergies.

Why Do Allergies Occur in Dogs?

Allergic reactions occur when the body’s immune system is activated by a foreign substance. Some animals’ systems are more sensitive, others less so. Allergies can also develop suddenly, and to a substance that’s never triggered a reaction in the past.

According to Dr. Michael Levine, DVM, the allergic reaction can take one of four basic forms:

1. Dermal Effects: Itching involves the skin. This itching can be localized or it can affect the dog’s entire body. Welts, bumps, and rashes are common manifestations of allergies.
2. Respiratory Effects: Respiratory symptoms include runny nose, discharge from the eyes, wheezing, coughing and even constriction of the airway.
3. Digestive Effects: An allergy affecting the digestive system can result in vomiting, diarrhea and chronic upset.
4. Systemic Effects: In serious cases, anaphylaxis results. This acute reaction can result in facial swelling, swelling of the airway, swelling of the feet, sudden drops in blood pressure, arrhythmia, seizure and death.

Allergies can be a chronic problem, or episodic in nature.

Allergens can take many forms: they can be inhaled like pollen and chemicals; they can be ingested as in the case of medication or food allergies; they can result from contact with the skin, also known as contact dermatitis; and they can be injected, as in the case of vaccinations.

What Are the Symptoms of Allergies?

A dog with allergies can display a vast array of symptoms, some subtle, others more obvious.

Common symptoms that can indicate an allergy in a dog include:

• Nasal discharge
• Ocular (eye) discharge
• Swelling of the face or paws
• Biting at the paws or legs
• Itchy skin
• Dry, flaky skin
• Red, swollen skin
• Welts
• Bumps and discoloration on the skin’s surface
• Hives
• Wheezing
• Difficulty breathing
• Coughing
  
• Sneezing
• Diarrhea
• Vomiting
• Seizure
• Muscle Tremors

In addition, dogs who are suffering from acute allergic responses are prone to exhibiting generalized signs of distress and discomfort, including panting, salivation, restlessness, whining, lethargy, and refusal to eat or drink.

How are a Dog’s Allergies Diagnosed?

“Allergies are perhaps one of the most difficult problems to effectively diagnose and treat,” explained Dr. Levine, who added, “Allergies are often explored when all other potential causes – like a respiratory infection, virus or parasites - are eliminated. And identifying the specific cause of a dog’s allergy is often a system of trial and error.”

Controlling the dog’s exposure to allergens is the first step in diagnosis.

“I tell clients to keep a log. Write down what your dog eats, places your dog visits, note the daily pollen count, and write down what chemicals and products are used in the home. You’ll also record the dog’s daily condition, rating his symptoms on a scale of 1 to 10. Patterns usually develop based on exposure to various potential allergens and this method usually gets you in the ballpark,” Dr Levine added.

Systemic trial and error is also key in many instances. Food allergies are among the most difficult allergies to diagnose. So systemically eliminating and then re-introducing ingredients in the dog’s diet can help owners identify the specific food that’s causing the problem.

What is the Treatment for a Dog With Allergies?

Treatment varies depending on the dog's allergy.

A dog with a food allergy requires no “treatment” per se – owners simply need to ensure that the dog’s diet does not include the problematic food item(s). Potato and Duck kibble formulas are often well-tolerated in sensitive pets, while other pets require a homemade diet.

For cases where the dog’s exposure to the allergen cannot be controlled – such as the case of a seasonal allergy – anti-histimine medications are typically effective in controlling the immune system’s response, thereby relieving the symptoms.

In cases of skin allergies in dogs, secondary infection is common due to the itching and biting at the skin. So antibiotic treatment is often required to heal the infection that results.

One frequent location for secondary infection is the paws and paw pads. Biting and chewing of the feet is a common occurrance as the result of allergies, and foot injuries are particularly difficult to heal without oral antibiotics and proper paw injury care.