Irritated eyes. Runny noses. Constant itching. Allergies plague millions of people every year. Unfortunately for our four-legged friends, allergies don't discriminate. Dog allergies can be a constant nuisance and cause quite a bit of agitation and distress, particularly during spring and summer. Knowing that (wo)man's best friend is suffering just as much as we are makes pet owners wonder what they can do to help.

Recently, many pet owners have begun questioning whether the same human-made allergy medications are safe and effective for their dogs. In this article, we will cover what you need to know about Claritin for dogs. Although it is among the most popular allergy medications for people, pet owners should know about a few things about Claritin before giving it to their dog.

What is Claritin for Dogs

claritin for dogs

In people, Claritin (scientific name, Loratadine) alleviates allergy symptoms and mild to moderate allergic reactions that often result in hives. In many cases, veterinarians prescribe Claritin for dogs for the same reasons that the drug is prescribed for people.

Be aware that Claritin does not cure allergies; allergies are only manageable, not treatable. Your dog will still suffer from the unpleasant symptoms when not taking the medication. Claritin temporarily relieves the symptoms and helps make the seasonal changes more bearable for Fido.

How Does Claritin Work

When histamines attach to the H-1 receptors on the smooth muscles and small blood vessels, they trigger an allergic reaction that includes sneezing, itching, irritated and watery eyes, and a runny nose. Claritin is an antihistamine. Antihistamines prevent histamines from attaching to the H-1 receptors, therefore preventing an allergic reaction.

What is Claritin Used For

Allergy Relief 

Just like people, dogs with allergies suffer from itchy, red eyes and runny noses. Affected dogs can also suffer from extremely irritated and itchy skin, which can cause uncontrollable fits of scratching to relieve the agitation. This constant itching, biting, and scratching can lead to many skin issues, including deep scarring and bacterial infections from open wounds. 

When dog allergies are at a high, veterinarians may prescribe Claritin to relieve allergy symptoms and therefore prevent more skin damage.

dog with owner in flower field

Canine Atopic Dermatitis

Additionally, Claritin can help alleviate symptoms of canine atopic dermatitis, which is a chronic, inflammatory skin condition resulting from hypersensitivity to normal environmental substances like dust. Affected dogs are incredibly itchy, leading to constant licking and biting in an attempt to relieve allergy symptoms. If atopic dermatitis is not treated promptly, it can quickly lead to the development of hot spots and bacterial infections. 

Clinical Signs of Allergies

Before considering whether Claritin can help your dog, pet owners must be able to recognize allergy symptoms and understand that allergies and allergic reactions have variable severity. Even if your dog's symptoms are relatively mild, your dog may still find relief from an allergy medication.


Sneezing is one of the most obvious signs of allergies in people and animals and is often prompted by an environmental allergen like pollen. Of course, occasional sneezing is normal. Persistent sneezing, particularly if it occurs simultaneously with an event (e.g., opening the windows, spraying perfume), is likely allergy-related.

Nasal discharge can accompany sneezing. When sneezing results from allergies, the discharge is typically clear. Yellow or green discharge indicates an infection requiring treatment.

dog sneezing


Wheezing may also be caused by certain environmental allergens, particularly if the dog has any pre-existing breathing issues. Before prescribing an allergy medication like Claritin, your veterinarian will need to definitively identify allergies as the cause of wheezing and rule out other causes, such as bacterial pneumonia.


Dogs with allergies may cough, especially if they have a medical condition that affects their breathing (e.g., asthma). Once again, your vet will need to rule out serious health issues, like heart failure, that could be causing the coughing. 


If a dog’s allergic reaction narrows the airways, snoring will often ensue.

Chronic Ear Infections

It may surprise readers to learn that chronic ear infections are a telltale sign of allergies in dogs. If your dog is constantly pawing at their ears or has persistent wax buildup within the ear canal, ask your vet whether allergies may be to blame.

Itchy, Irritated Skin

Itchy, irritated skin is one of the most common signs of allergies in dogs. Although people often associate itching with bug bites, dogs can experience itchy skin from just about any allergen. Itchy skin on the back and base of the tail indicates flea allergies, while itchy, irritated skin on the paws and ears typically indicates food allergies.

dog scratching

Red, Itchy Eyes

Like people, dogs with allergies will often experience red, itchy eyes. Be mindful that, although eye discharge is an allergy symptom, it may also indicate something more severe, like a bacterial infection. If your dog has eye irritation, do not automatically assume allergies, as the irritation may require antibiotic treatment.

Gastrointestinal (GI) Issues

Allergy symptoms in dogs, particularly food allergies, also include GI problems. Diarrhea and vomiting often occur if a new food doesn't agree with Fido's digestive tract.

Swollen Itchy Paws

Finally, swollen, itchy paws are a sign of allergies in dogs. If your dog is constantly biting or licking their paws, swollenness and tenderness will often follow. 

Symptoms of an Allergic Reaction

Although occasional mild allergies are usually little more than an annoyance, severe allergies must be treated as a medical emergency because of the potential for anaphylaxis, which is a form of shock that can be fatal if not treated immediately.

Clinical signs of anaphylaxis include:

  • Seizures

  • Collapse

  • Trouble breathing

  • Excessive vomiting

  • Excessive lethargy

  • Uncontrollable urination

  • Uncontrollable bowel movements

If you think your dog is having a severe allergic reaction, seek veterinary treatment immediately.

What Causes Allergies in Dogs

We briefly touched on how certain allergens, like environmental or food allergens, can cause specific symptoms. Pet owners should understand that many factors can lead to dog allergies and that these factors may be trickier to pinpoint and therefore harder to prevent. Most allergen triggers fall into one of four categories: environmental, food, medication, or flea and tick. 

Environmental Allergies

Environmental allergies are the most common reason that veterinarians prescribe Claritin for dogs. They are also the toughest to avoid, as it is nearly impossible to completely prevent every single environmental trigger.

Environmental allergens are widely variable and include:

  • Dust

  • Pollen

  • Smoke

  • Dander

  • Perfume

  • Laundry detergents

  • Household cleaners

  • Various trees, grass, and plants

As you can see, just about anything can cause your dog's environmental allergies. Seasonal environmental allergies are particularly problematic because your dog’s allergies can flare up depending on what’s in bloom. In these cases, Claritin may be recommended.

Food Allergies

In some cases, your dog may have a food allergy that is causing GI upset, such as diarrhea or vomiting.

Unfortunately, identifying specific food allergen is often quite challenging. Diagnosing a food allergy involves feeding an elimination diet, in which a dog eats nothing but a hypoallergenic diet (no treats or human food allowed!). Then, slowly, specific food is integrated back into the dog's diet to see what’s causing the allergic reaction. Although the process is tedious, it will be rewarding if the veterinarian can find the food “culprit” and keep it out of your dog’s diet moving forward.

Allergies to Medications

Many dogs have medication allergies that vary in severity. In some cases, the allergic reaction may be mild and Claritin may be all that's necessary to relieve the symptoms. In other cases, severe reactions to new medications may occur; Claritin would not be enough to relieve the reaction and medical intervention would be necessary.

For this reason (among many others), pet owners must keep an eye on their dog whenever a new medication is introduced. It may very well be the difference between life and death for your dog.

Allergies to Fleas and Ticks 

Finally, flea and tick allergies are very common in dogs. A single flea bite can leave Fido itching for weeks. Luckily, dog owners can take preventative measures to avoid this type of allergic reaction. Whether you choose a conventional flea medication or an all-natural alternative, flea and tick prevention is a must. 

Other Uses of Claritin for Dogs

Veterinarians can prescribe Claritin for more than just allergies. Read on for more Claritin uses! 

Mast Cell Tumors

Your veterinarian may prescribe Claritin to treat inflammation associated with mast cell tumors. Mast cells are full of histamine. When those cells become cancerous, they release massive amounts of histamine in a process called degranulation. Thus, many mast cell tumor symptoms closely resemble those of an allergic reaction and can be relieved with Claritin. Claritin is by no means a cure for mast cell tumors, but it can reduce their symptoms.

Vaccine Side Effects

Some dogs have allergic reactions to vaccines. Veterinarians may prescribe Claritin for these dogs to prevent vaccine-associated reactions, particularly if your dog has reacted to vaccines before.

Claritin Side Effects

Like other conventional antihistamines for dogs, Claritin has potential adverse reactions that pet owners should know about before administering it.

Potential adverse reactions include:

  • Vomiting

  • Dry mouth

  • Drowsiness

  • Increased thirst

  • Urinary retention

  • Excessively dry eyes

  • Behavioral changes

  • Changes in bowel movement consistency and regularity

dog with sad eyes

Dog owners may wonder whether these potential adverse reactions are worth easing mild allergy symptoms. It truly comes down to each pet owner's individual decision. Also, be mindful that these are potential adverse reactions; your dog may not experience any of them while on Claritin. Nonetheless, if you have any concerns about giving Claritin to your dog, discuss these concerns with your veterinarian and determine what is best for your dog.

Additional Precautions

Before prescribing Claritin, your veterinarian should know about your dog’s pre-existing health issues and medication allergies. For instance, your dog should not take Claritin if they have an allergy to loratadine (Claritin) or desloratadine (Clarinex). Additionally, dogs with liver or kidney disease should be closely monitored when taking Claritin.

Claritin Dosage

Claritin dosage depends on several factors, primarily body weight and allergy severity. The recommended dosage is 0.2 mg Claritin/pound of body weight. All dogs are different, so follow your veterinarian’s prescribed dose.

Which Claritin Formula is Safe?

For people, many Claritin formulations are available. However, not all human Claritin formulations are safe for Fido.

Plain Claritin or Children's Claritin

The only versions of Claritin deemed safe for dogs are plain Claritin and Children's Claritin. Additionally, stick to the tablet form to ensure that the active ingredient is solely antihistamine.


*IMPORTANT* NEVER, EVER GIVE YOUR DOG CLARITIN-D. Claritin-D contains pseudoephedrine. Pseudoephedrine can be lethal in dogs, even in the smallest amount. If you think your dog has ingested pseudoephedrine, call the ASPCA Pet Poison Hotline at (888) 426-4435.

Claritin Overdose in Dogs

When dog owners correctly administer Claritin to their dogs, overdoses are very uncommon. However, when they do occur, they can be extremely dangerous. Therefore, dog owners must ensure that they are administering Claritin appropriately.

Additional Allergy Medicine for Dogs 

When choosing an antihistamine for dogs, several factors should be considered. Many antihistamines come in chewable, dissolvable, and liquid forms. However, many antihistamines contain artificial sweeteners (including xylitol) that can be incredibly toxic and even fatal when consumed.

The top three options of antihistamines for dogs are:

  1. Diphenhydramine (Benadryl)

  2. Cetirizine (Zyrtec)

  3. Loratadine (Claritin)

Benadryl for Dogs 

Benadryl is the most commonly prescribed over-the-counter human medication for dogs. It works like Claritin to manage allergies and allergic reactions. However, unlike Claritin, Benadryl is also used as a mild sedative and is often recommended to manage anxiety in dogs, particularly while traveling. Veterinarians may also prescribe Benadryl to alleviate motion sickness in dogs.

Zyrtec for Dogs

Zyrtec is often recommended for dogs suffering from allergic reactions associated with allergic contact dermatitis and atopic dermatitis. It relieves symptoms such as inflammation, hives, itching, and swelling.

Read the Label! Ask Your Vet!

As with all medications, you must read the label. Some antihistamines contain additional medications that help relieve cold and flu symptoms. These additional medications may not be good for your dog.

Why Choose All-Natural Alternatives

It isn't always discussed that these antihistamines work in only about 30% of dogs that take them. The other 70% of dogs don’t experience much allergy relief and may also experience adverse reactions.

Luckily, some safe and effective all-natural remedies can be used as alternatives to conventional antihistamines and can help reduce dog inflamation naturally.

Claritin for Dogs: The Bottom Line

Our pets mean the world to us and we would do anything in our power to ensure their happiness and well-being. For treating and preventing seasonal allergies, Claritin may help your dog get the relief they need and deserve. However, in other cases, conventional antihistamines for dogs may not help as much as you want them to. Other dogs may experience adverse reactions with very little allergy relief.

As a responsible pet owner, you should take the time to learn as much as you can about a new medication before giving it to your dog. Knowledge is power. The more you know about a drug, the better you’ll be able to make a decision that most benefits your dog's wellbeing.