Can I Give My Dog Benadryl for Itching?

Your dog’s itchy skin is a symptom of many different conditions and is not an official diagnosis.  

When dogs itch, they scratch, bite at their skin and paws, lick themselves excessively, and even rub and roll on the carpet or grass to scratch that itch. And it always seems to be worse at night, hearing your beloved pup scratching away, keeping you awake, and neither of you get any rest.  

Some pet owners wonder, “Can I give my dog Benadryl for itching?” 

Though Benadryl is a very safe drug used commonly in dogs, you should still never give an over-the-counter medication without speaking to your veterinarian first.  

Depending on the diagnosis of what’s causing the underlying irritation, your veterinarian may have you give Benadryl to relieve the itching. Let’s talk about what Benadryl is, how it works, the recommended dose, risks and side effects, as well as other treatments to consider.
What is Benadryl and How Does It Work for Dogs?

Benadryl (drug name diphenhydramine) is an antihistamine that works by blocking a certain natural substance, histamine, that a body makes during an allergic reaction. It works by blocking the receptors that receive histamines in the body. This relieves many of the symptoms associated with allergies, like itching, sneezing, and hives. 

The body still produces histamines, but the receptor antagonist blocks the receptors from registering the histamines.  

Veterinarians most commonly recommend that pet parents give their dogs Benadryl to prevent or treat mild allergic reactions and to reduce nausea and vomiting associated with motion sickness or vestibular disease. Benadryl is not approved by the FDA for use in animals. Therefore, there are no Benadryl formulations specifically for pets. 

The human medication is used “off-label.” Because itching is a generalized symptom of many different conditions, it is possible that Benadryl will not help the issue long term, as it is not treating the underlying cause of the itch. It can be used for immediate relief before you can get your dog to the veterinarian to see why they are itchy in the first place.  

While scratching might temporarily ease itching symptoms, it can also cause further irritation, or worse, infection. In this case, Benadryl may not be effective for these serious conditions, such as infection or chronic skin disorders. Let’s dive a little deeper into this.

Can Benadryl Help with Dog Itching?

Benadryl is commonly recommended for use in dogs with mild-to-moderate allergies. Seasonal allergies, food allergies, environmental allergies, and allergic reactions to bites from snakes and insects all respond to Benadryl.

In most cases it is used to treat itchiness in dogs caused by skin allergies. It also reduces many of the other symptoms, including: 

• Hives
• Swelling and inflammation, 
• Redness
• Runny nose and eyes
• Coughing
• Sneezing and 
• Anaphylactic reaction.  

Before you reach for Benadryl, consult your veterinarian about your dog’s symptoms. 

Allergy symptoms like itching and red eyes may also be signs of more serious conditions; In some cases, giving your dog Benadryl can worsen your dog’s condition.  

For instance, red, irritated eyes could be a symptom of allergies, or it could also be a sign of glaucoma or dry eye, which Benadryl will not help treat. Your veterinarian will also be able to tell you whether Benadryl will interact with any other medications that your dog is taking.  

If your dog has any of the following conditions, only use Benadryl after consulting your veterinarian:  glaucoma, heart disease, liver disease, some lung diseases, hypothyroidism, hypertension, pregnancy, or seizure disorders. Benadryl should also not be administered if your dog is having a severe allergic reaction, instead you should head straight to the veterinarian!  

Symptoms of this include:

• Swelling of the face, lips, or eyes
• Trouble breathing
• Excessive panting or 
• Severe hives.  

Benadryl may not help with other skin conditions, such as bacterial or fungal infections, flea bites or flea allergic dermatitis, atopic dermatitis, seborrheic dermatitis, or acute moist dermatitis or hot spots. In the case of any of these issues, other treatments would be required by your veterinarian.

Benadryl Dosage for Dogs

Before dispensing any medication to your dog, it is best to consult with your veterinarian regarding an approved dose. 

Especially for small breed dogs, senior dogs, pediatric dogs, or dogs with health conditions listed previously. 

Use the Benadryl that only contains diphenhydramine. 

In addition, many formulations of the drug are combined with other potentially dangerous medications, such as Tylenol, alcohol, or xylitol (a sugar substitute that is toxic to dogs). Never use time-release capsules for dogs. Your veterinarian can prescribe diphenhydramine tablets for dogs. 

According to the Merck Veterinary Manual, the standard dose for Benadryl is 2–4 milligrams per kilogram of body weight, or 0.9–1.8 milligrams per pound. Therefore, a simply calculated dose is 1 mg of Benadryl per pound of your dog’s weight, given two to three times a day. For example, a 10-pound dog might receive a 10 mg dose in the morning, afternoon, and evening.

Benadryl comes available in multiple forms and doses. It is available in tablet, capsule, and liquid form. The tablets and capsules contain either 25 mg or 50 mg of diphenhydramine, which would be the appropriate size for a 25-pound or 50-pound dog, respectively.  

For larger dogs, multiple tablets or capsules would equal their appropriate dose. On the other hand, you can split 25 mg tablets in half to fine-tune your dog’s dose. For example, a half of a 25mg tablet would be an appropriate dose for a 12-pound dog.  

Children’s chewable or liquid Benadryl are other options for small dogs. A full chewable children’s tablet contains only 12.5 mg of diphenhydramine and can be cut in half for dogs that weigh less than 10 pounds. Children’s liquid Benadryl contains only 2.5 mg/ml. Again, you must avoid any formulation that contains alcohol, xylitol, and decongestants. For instance, Benadryl-D contains a decongestant that can be toxic to dogs!

Potential Side Effects of Benadryl in Dogs

There are side effects associated with using Benadryl for dogs that all owners should be aware of before administering it. Most side effects occur within the first hour of giving the medication, so be sure to watch your dog carefully during this time. 

Common side effects associated with using Benadryl for dogs include: 

• Drowsiness
• Dry mouth
• Urinary retention
• Hypersalivation
• Increased heart rate and 
• Rapid breathing.  

It can even cause hyperactivity in some dogs.  

Rarer side effects can include diarrhea, vomiting, decreased appetite, or even increased appetite. 

Though Benadryl is a safe drug with a wide dosage range, it is still possible for dogs to overdose on this drug.  Signs of an overdose include: 

• Hyperactivity
• Agitation
• Muscle tremors
• Fever
• Incoordination
• Decreased energy (lethargy)
• Slowed or difficult breathing
• Increased heart rate
• Dilated pupils
• Agitation
• Constipation or 
• Even seizures.  

In extreme cases, an overdose can cause hyper-excitability of the central nervous system, which can be fatal!  

If you suspect your dog has overdosed on Benadryl, contact your veterinarian or emergency veterinary hospital immediately!  

Some dogs can develop an allergic reaction to Benadryl, ironically. If your dog starts having symptoms of an allergic reaction, seek veterinary care immediately. As mentioned previously, dogs with the following conditions should not take Benadryl without veterinary approval: glaucoma, heart disease, liver disease, some lung diseases, hypothyroidism, hypertension, pregnancy, or seizure disorders.

Alternatives to Benadryl for Dog Itching

Benadryl has been available for a long time, and continued research has led to the development of treatments that may be more effective than diphenhydramine.  

Apoquel is a prescription medication that targets allergic itching more effectively than antihistamines. It works on itch neurons within the skin, preventing the transmission of the itch signal to the brain and the subsequent scratching behavior. This then gives your dog relief while the underlying cause of the itch can be determined by your veterinarian.  

Cytopoint is a prescription injection that treats allergic dermatitis in dogs and provides long-lasting relief for chronic itching. The injection is given every 4 to 8 weeks, depending on the dog’s needs. Itching usually improves within a few days, is effective for 4-8 weeks, and is often used in combination with other allergy management treatments. 

Steroids are another prescription medication option that your veterinarian may prefer. Oral or injectable steroids are often used for short term control of itch, although their side effects make them less desirable. Short term side effects can include increased thirst, increased appetite, increased urination, and behavior changes. Topical steroids can be helpful when itch is localized to one area.

You may be interested in natural remedies instead of medications. Omega-3 supplements, also known as fish oils, help improve skin health and reduce inflammation, which should decrease the itch. Colloidal oatmeal baths can help soothe your dog’s itchy skin and relieve irritation. Even coconut oil has anti-inflammatory properties and moisturizing effects that can help reduce the itch.

When to See a Veterinarian

You may need to make an appointment with your veterinarian to determine the underlying reason for the itch. If the itching is accompanied by hair loss, lesions, or sores, please make an appointment with your veterinarian. Especially if there are any open wounds or breaks in the skin, a secondary infection can set in as your dog continues to traumatize its skin by scratching at it. 

If your dog is excessively licking or biting at their skin or paws, you should have them evaluated by the vet. This, again, can lead to infection or further chronic issues. 

If your dog is scratching because of fleas, Benadryl is not going to cure it. Your veterinarian can recommend prescription or over the counter flea treatments.  

Food allergies can also cause a dog to itch excessively, but Benadryl may not help this condition. Most times a food change is needed, feeding a novel protein diet or allergy testing may be required.  

Lastly, if your dog is having a severe allergic reaction, please seek veterinary care immediately.  Symptoms of this include: 

• Swelling of the face, lips, or eyes
• Trouble breathing
• Excessive panting or 
• Severe hives.  

Benadryl may be able to provide quick relief for a minor allergy or may be able to settle them down enough that you both get some rest. Though it is possible that your pet needs veterinary care for severe allergic reactions or chronic health problems.  

If you choose to administer Benadryl to your dog, it is recommended to consult with your veterinarian first for proper dosage.

Beware of the side effects and contact your veterinarian if your dog experiences any of the side effects mentioned. Though Benadryl is an option for your itchy pet, you may want to start with a more benign, natural remedy first. Or on the other hand, if the Benadryl is not working to your desired effect, please contact your veterinarian to have your pet evaluated for other options. There is relief for your dog and for you!