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The Three Most Common Allergy Medicines for Dogs

By Colleen Williams and medically reviewed by JoAnna Pendergrass, DVM
published: May 29, 2018 - updated: January 19, 2023 • 3 min. read
allergy medication for dogs

Key Takeaways

  • Dogs can be allergic to fleas, food, and environmental factors.
  • Dog allergies may be seasonal.
  • Allergy medications for dogs are over-the-counter antihistamines, corticosteroids, and Apoquel.
  • Get pet insurance early before allergy symptoms are present so that allergies will be covered if they become an issue later in life.

An allergy is the end result of the body’s immune system overreacting to a foreign substance. These foreign substances that put the immune system into overdrive are called allergens.

There are several main types of allergies in dogs: flea, food, and environmental (also known as atopy or atopic dermatitis). Atopy is an overreaction to substances in the environment, like pollen, grass, and dust. It leads to pesky symptoms that include itching, scratching, biting, and chewing.

Just like in humans, environmental allergy symptoms in dogs typically pop up seasonally. However, these symptoms can be similar to those seen with other allergy types, so consult with your vet before giving your dog a dose of allergy meds. (If you’re concerned about food allergies, talk to your vet, and learn more about dog food allergies here.)

With the allergy meds listed below, your vet will first need to diagnose the specific type of allergy that your dog has, then prescribe the appropriate drug and drug dose.

Popular Anti-Allergy Medicine Choices for Pups

Over-the-counter (OTC) Antihistamines: Benadryl, Claritin, Zyrtec

These OTC meds work well for environmental allergies but come with a myriad of negative side effects. Also, according to vets, these meds are effective in only 30% of dogs. Furthermore, while they may work in the beginning, they may lose effectiveness over time.

One common side effect of OTC allergy meds is sedation, especially in pets who are already on anti-depressants, certain pain relievers or seizure medications. In some dogs, these meds can cause hyperactivity.

OTC allergy meds for humans may also contain a decongestant, which is dangerous for dogs. When selecting an allergy med from the store, make sure that it contains only antihistamine.

The dosage is never the same as it is for humans, so your vet will determine the proper dose for your dog. The cost is anywhere from $5-$20, depending on your retailer and quantity purchased.


The not-messing-around option is much stronger: corticosteroids (also called “allergy shots,” unless they’re taken orally). Steroids are much more effective at treating allergy symptoms but can come with risky side effects, such as a suppressed immune system, increased risk of diabetes, and, in the short term, increased hunger, urination, and thirst.

Steroids cannot be used without the direction of a vet. And, your dog will need to have bloodwork and urinalyses performed regularly if the steroid treatment is long-term.

The good news? Allergy shots have up to an 80% success rate! The bad news? All of those side effects that are listed above, and more. However, the ultimate pro is that your pet will see relief.

A prescription for oral meds administered at home may cost around $40 for a 30-day supply, whereas vet visits for an injection may cost $50 to $150 each time.


Apoquel is not a steroid or antihistamine. Instead, it belongs to a class of drugs called “Janus kinase inhibitors,” which work on the brain signals that result in itching and inflammation and suppress the overactive immune system. What’s really great about Apoquel is that itchy dogs start experiencing relief within just 4 hours of taking the drug. Apoquel controls the itchiness within 24 hours.

Common side effects include vomiting and diarrhea. Also, it is not to be used in dogs <1 year old and may increase the risk of infection and cancer. The capsules are easy to administer. For a medium- to large-sized dog, this will cost approximately $3 per pill (Rx of 28 pills comes to a total of $84).

To sum things up, if your dog has allergies, several types of allergy meds are available that can help your dog experience relief from uncomfortable allergy symptoms. Talk with your vet to determine the best allergy management strategy for your dog.

Enroll your kitten or puppy early so chronic conditions like allergies will be covered as long as symptoms were not present upon signing up. Find out how Healthy Paws pet parents not only get their furry four-legged friends some much needed relief but also save money by getting a free quote.

The content is not intended to be a substitute for professional veterinarian advice, diagnosis, or treatment. Always seek the advice of your veterinarian or other qualified health provider with any questions you may have regarding a medical diagnosis, condition, or treatment options.

colleen williams
By Colleen Williams

Over the past decade, Colleen has written about health, wellness, beauty, and even pets for The New York Times, The Cut, Refinery29, xoVain, Healthy Paws Pet Insurance, and Seattle Met Magazine, as well as many beauty brands. She has a BFA in Art History from the University of New Mexico and an AAS in Fashion Design from Parsons School of Design in New York.

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joanna pendergrass
By JoAnna Pendergrass, DVM

JoAnna Pendergrass, DVM, is a veterinarian and freelance medical writer in Atlanta, GA. After graduating from the Virginia-Maryland College of Veterinary Medicine with her veterinary degree, JoAnna completed a 2-year research fellowship in neuroscience at Emory University. During this fellowship, she learned that she could make a career out of combining her loves of science and writing. As a medical writer, JoAnna is passionate about providing pet parents at Healthy Paws with clear, concise, and engaging information about pet care. Through her writing, she strives not only to educate pet parents, but also empower them to make good health decisions for their pets. JoAnna is a member of the American Medical Writers Association and Dog Writers Association of America.

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