Treatment with anti-inflammatory drugs, such as corticosteroids or antihistamines, will quickly block the allergic reaction in most cases. Fatty acid supplementation in the diet can sometimes improve the response to steroids and antihistamines.
Veterinarians use diphenhydramine, commonly known by the brand name Benadryl, for dogs on a regular basis to treat allergies, travel anxiety, and motion sickness.
Best treatment: Antihistamines
Antihistamines are commonly used to treat dog allergies. Their histamine-blocking quality tackles airborne allergens and reduces symptoms in your pup. The safest over-the-counter options for your dog include Benadryl, Zyrtec, Claritin, and Allegra.
Cetirizine (Zyrtec® or Reactine®) is one of the most commonly used over-the-counter antihistamines recommended by veterinarians. Claritin® can be used but is not typically recommended by veterinarians as some forms of Claritin® contain decongestants such as pseudoephedrine which is very toxic to dogs.
Zyrtec is one of the safer medications you can give to your dog, so as long as you do so correctly and under your vet's guidance, your pet should be good to go. Zyrtec is also a difficult medication for a dog to overdose on. They have an extremely high tolerance for it, so long as they aren't allergic to it.
You can safely give Zyrtec to your dog up to 20 mg per day.
Fexofenadine, commonly known as Allegra® or Telfast®, is a second generation antihistamine drug that may be used for dogs and cats to control itching and other signs related to allergic conditions.
Over-the-counter (OTC) antihistamine tablets include fexofenadine (Allegra Allergy), loratadine (Claritin, Alavert) and cetirizine (Zyrtec Allergy); OTC antihistamine syrups are available for children. Prescription antihistamine tablets, such as levocetirizine (Xyzal) and desloratadine (Clarinex), are other options.
The dose is 1 mg/kg twice daily. fexofenadine (Telfast®) – this is a second gen. It is available as 60 mg capsules and 120 or 180 mg tablets. The dose is 5–10 mg/kg once or twice daily (don't use if your dog is on ketoconazole or a macrolide antibiotic)
Quercetin is a bioflavonoid that provides natural allergy relief for dogs reducing symptoms like itching, scratching, licking and chewing. Many veterinarians suggest quercetin because it is a safe, natural antihistamine for dogs. In fact, quercetin is often referred to as "Nature's Benadryl".
Apple cider vinegar, coconut oil, or aloe vera can be put on the skin to calm any itching. A relaxing oatmeal bath can relieve itching, burning, and dry skin.
Apoquel is an oral tablet you can give your dog daily for his allergy symptoms. It works by suppressing your pup's immune system so he doesn't have such a strong reaction to the things he's allergic to.
Antihistamines and fatty acid supplements can reduce the allergic response. Special shampoos and rinses can help alleviate symptoms too. In severe cases, your veterinarian may prescribe steroids to help with intense itching.
Pet allergy relief
When you can't live without your pet, a medicine for dog and cat allergies can help control your pet allergy symptoms. ZYRTEC® starts working at hour 1 and stays strong day after day, so you can reduce your cat and dog allergy symptoms. Learn more about ZYRTEC®.
Zyrtec is a popular second-generation antihistamine first prescribed to people. However, more and more veterinarians have started prescribing it to dogs in pain with pruritus caused by allergic dermatitis. The reason for this is Zyrtec is rather low-risk, however, it's not as effective as the drug Apoquel.
Antihistamines are usually safe but can make some dogs drowsy and others hyperactive. OTC antihistamine preparations may contain other ingredients such as decongestants that are not safe for dogs. Read the label carefully to ensure that the product only contains antihistamine.
Here's the recommended Zyrtec dosage for dogs based on their weight: Less than 10 pounds: 2.5 milligrams (half of a 5-milligram pill or a quarter of a 10-milligram pill) 10–50 pounds: One 10-milligram tablet. 50+ pounds: Up to two 10-milligram tablets.
Cetirizine (Zyrtec®, Reactine®) is an antihistamine used to treat and prevent pruritus (itching) associated with atopic dermatitis, urticaria (hives), and insect bite reactions in cats and dogs. Its use is in cats and dogs is 'off-label'. Many drugs are commonly prescribed for off-label use in veterinary medicine.
Allergies in dogs are different than allergies in people. Histamines cause upper respiratory allergies in people, whereas cytokines (not histamines) cause itchy skin in dogs. For dogs with underlying allergies, antihistamines don't control the cytokines (signaling proteins) that cause inflammation and itch.
When accidentally ingested by dogs and cats, antihistamine poisoning can result in clinical signs of severe agitation, lethargy, sedation, aggression, abnormal heart rate, abnormal blood pressure, vomiting, diarrhea, inappetance, seizures, respiratory depression, and even death.
Avoid Zyrtec-D or any other formulations that may contain a decongestant. Pseudoephedrine, a common decongestant in human medications, is highly toxic to dogs.
Other safe antihistamines for dogs include Claritin (loratadine) and Zyrtec (cetirizine). They produce less sedation than Benadryl does but could still make your dog drowsy. Warning: Make sure your OTC allergy medicine only contains antihistamines.