The Water Bowl
Breed & Health Resources

Allergic Reactions in Dogs

By Dr. Kallie Sesti

up close of pug licking paw

Just like in people, dogs can have an allergic reaction to just about anything! Reactions can range anywhere from a mild itch to a life-threatening event.

What Is an Allergy?

An allergy is the result of the immune system’s response to a traditionally harmless substance. An allergic reaction occurs when the body comes into contact with a substance, or allergen, which causes discomfort and/or illness. Upon repeated exposure to an allergen, the severity of the body’s reaction may increase. Eventually, an overreaction to an allergen may occur, resulting in an anaphylactic immune response. Anaphylaxis, or a life-threatening reaction, can occur when the body produces antibodies which “attack” the antigen.

What Are Common Causes of Allergies In Dogs?

Common allergies in dogs are due to fleas, foods, chemicals in the environment (air fresheners, laundry detergents, household cleaners, etc), seasonal airborne allergens (pollens, etc), non-seasonal allergens (molds, dander, vaccines, medications, etc), and contact allergens (bug bites, bee stings, etc).

What Allergy Symptoms Should I Look for in My Dogs?

Mild to moderate allergies can range from occasional to constant foot licking, generalized itching all over the body (rubbing against furniture, rolling on back), restlessness, redness of the skin with or without crusts, thinning hair, and/or hair loss. Other signs may include coughing, sneezing, panting, and asthma. Tummy upset, such as vomiting and/or diarrhea may result. Self-trauma from chronic itching and biting can lead to secondary skin infections. Pets also tend to be more prone to chronic ear infections from underlying allergies.

Severe allergic reactions occur much less frequently. Anaphylaxis may occur from any allergen, but is more commonly seen due to bug bites, vaccines/drugs, and/or foods. Over reactions to these allergens can rapidly result in facial swelling, such as the eyes, ears, lips, and throat. Dogs may break out in hives, or itchy red skin swellings, and feel hot to the touch. Rapid onset of vomiting and/or diarrhea, trouble breathing, collapse, shock, and death may also occur.

Can Dogs be Allergic to Cats?

Yes! Dogs can be allergic to cat dander, just like people. They can also be allergic to human dander.

How Can I Treat My Dog’s Allergies?

Allergies are not curable, but they can be managed. It is best to avoid the allergen or limit exposure if avoidance is not possible. For mild allergies, dogs can take diphenhydramine (Benadryl®) or loratadine (Claritin®) on a regular basis. Newer prescription medications, such as Apoquel® and Cytopoint®, are specifically targeted to reduce itching. Steroids may help reduce the itch and inflammation, but must be used cautiously long term and are not safe with certain underlying health conditions.

Feeding trials may be performed if a food allergen is suspected. Food-allergic pets may trial a novel protein or a hypoallergenic diet. These specialized prescription diets are designed to reduce or eliminate exposure to the known allergens. Since not all environmental allergens can be eliminated, there are prescription diets formulated to reduce reactions. Therefore, these therapeutic diets help control discomfort by reducing irritations causing itching, runny eyes, sneezing, etc.

Alternatively, a veterinary dermatologist can perform allergy testing to identify the allergens which trigger a pet’s allergic reactions. Immunotherapy, or allergy injections, can then be administered under the skin to desensitize a pet to those identified allergens.

When Should I Take My Dog to the Vet for an Allergic Reaction?

Severe anaphylaxis can be life threatening and always warrants an emergency trip to the vet. Sudden facial swelling, trouble breathing, collapse, and shock can be fatal if aggressive care is not implemented immediately.

What Can I Expect at the Vet if My Dog Has an Anaphylactic Reaction?

Your veterinarian may start by giving an injection of Benadryl®, pain medications, and/or steroids. Hospitalization with IV fluids, blood pressure monitoring, and other supportive care may be warranted.

For pets with trouble breathing, intubation for oxygen support could be required. In these severe instances, an injection of epinephrine may be deemed appropriate. This is similar to people who carry an EpiPen® for emergencies. Critical care with 24/7 monitoring is imperative for the best outcome and survival.

It is important to learn the signs of allergies in pets to know when veterinary care is needed. Never administer any medications to your pet without first consulting a veterinarian.

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