Environmental Allergies and Your Pet


What are allergies?

Allergies occur when your pet’s immune system reacts to some type of substance. In the case of environmental allergies, the offending substances are found in the environment.  Dogs tend to have a higher occurrence of environmental allergens when compared to cats. Some dog breeds are also more prone to environmental allergies than others. This group includes, but is not limited to Terriers, Boxers, Dalmatians and Bulldogs.


Common environmental allergens

  • Pollen

  • Grass

  • Mold spores

  • Dust mites

  • Mildew

  • Animal and human dander

  • Dust (some cats may even be allergic to the dust from their litter)



Environmental allergies may be seasonal and are more prominent during certain times of the year. Seasonal allergies are usually associated with allergens found outdoors. Usually you will see an increase in symptoms in the spring and a decrease in symptoms in the winter (once the snow has fallen). If the offending allergen is a household environmental allergen you can expect to see symptoms year round.

If your pet is suffering from allergies, symptoms may include:

  • itchy and inflamed skin

  • sneezing

  • coughing

  • runny eyes

  • ear infections

  • swollen, sensitive paws

Treatment and management

Managing the environment

By keeping allergens low on and around your pet you can help keep them more comfortable. This can be accomplished by:

  • bathing your pet as directed by the veterinarian (and if your cat will tolerate it!) with a prescribed medicated shampoo

  • changing your furnace filter regularly

  • removing your pet from the room when you vacuum

  • regularly washing and replacing your pet’s bedding

  • wipe your pet down with a damp cloth when they come in from outdoors

  • using a low-dust type of cat litter


Blood testing and desensitization

Blood testing is available to pin point what exactly your pet is allergic to and to what extent. From there we can choose what allergens are the biggest offenders and a serum can be made up for desensitization. The serum is then given by injection or an oral spray. Most pets will show a favorable response to the desensitization and/or have their requirement for steroids or antihistamines reduced significantly.

Note: desensitization is slow, treatment needs to be done for 4-6 months, sometimes up to a year before a noticeable difference is seen.



Antihistamines such as diphenhydramine, hydroxyzine and ceterizine are all allergy medications frequently used by veterinarians. Antihistamines can be effective for treating allergies in pets, but since they only block the histamine receptors on the cells they sometimes are not as effective as steroids depending on how your pet is reacting to the allergen. Also, antihistamines usually work the best when they are taken before your pet is showing symptoms, which is sometimes hard to do. Antihistamines are typically given orally or by injection. The most common side effect of antihistamine therapy is drowsiness. Antihistamines are also not recommended for pets with liver disease.



Steroids such as predinsone, dexamethasone or hydrocortisone are commonly used in veterinary medicine. Steroids significantly suppress allergy symptoms. They can be given orally, applied topically or given by injection. When given orally, these drugs need to be weaned down and not stopped suddenly. Common side effects of steroid use include, but are not limited to increased thirst and appetite, behavioral changes such as being agitated, muscle wasting and weakness and suppression of the immune system.


Janus Kinase Inhibitor (dogs only)

A Janus Kinase Inhibitor such as oclacitinib (veterinary trade name: Apoquel) targets specific cytokines that cause itch and inflammation, relieving symptoms of allergic skin disease. This is an oral medication that is non-steroidal. It can be used safely for the long term and alongside many other medications such as NSAIDs, dewormers and allergen-specific immunotherapy.


An Immune-Modulator such as cyclosporine (veterinary trade name: Atopica) targets the immune cells involved in the allergic response, which helps to reduce itch and skin lesions. This is an oral medication that is also non-steroidal. Since this medication is an immunosuppressant it is contraindicated for pets with a history of any kind of cancer.  The most common side effects of cyclosporine involve the digestive system, causing vomiting and diarrhea. Since it is an immunosuppressant it can make your pet more susceptible to various infections and it can cause lethargy.


Monoclonal Antibody (dogs only)

A Monoclonal Antibody treatment such as lokivetmab (veterinary trade name: Cytopoint) specifically targets and neutralizes canine IL-31, an important cytokine involved in sending the itch signal to the brain. This is an injectable medication that will start working to relieve itchiness within 24 hours and will continue to work for up to 4-8 weeks, at which time the injection is repeated. This medication has no known drug interactions and it can be safely used alongside any other allergy treatment medications, NSAIDs and dewormers. It does not have any suppressive effects on the immune system and does not effect the liver or kidneys when it is being metabolized.