Common pet allergies and how to treat them

Last updated June 2021

Just like humans, pets can suffer from all sorts of allergies, including hay fever. Having an awareness of which allergens can trigger a reaction in your pet and knowing how best to treat their symptoms can help you manage their allergy effectively and enable them to carry on enjoying everyday life as normal.

AD can affect dogs and cats as young as 2 months old and occurs when allergens (environmental and/or food) enter the body through ingestion, inhalation or through contact with the skin. Some allergens are seasonal, causing the greatest problems when pollen counts are high during summer and early fall. Allergens, such as dust and mold, can affect pets all year round, and so monitoring when your pet’s symptoms occur can help to determine the cause.

Symptoms

Pruritus (itchy skin)

The most common symptoms of AD are itchy and inflamed (red) skin, rashes and alopecia (hair loss). Your pet may scratch, chew and lick their skin, rub up against surfaces and objects, and even lie on cold surfaces to soothe the irritation.

If left untreated, itchy skin can lead to open wounds and skin infections (such as hot spots). For this reason, you should contact your veterinarian if you notice any of these symptoms so they can advise you on the best next step for your pet.

Ear Infections

Another common symptom are ear infections. In fact, this is sometimes the first symptom of AD. Ear infections may be caused by bacteria and/or yeast.

Watery eyes

Environmental allergens can irritate your pet’s eyes and even cause conjunctivitis. Redness and swelling around the eyes, excessive tearing and squinting are all symptoms of allergic conjunctivitis, and this may also be accompanied by discharge, which can vary from clear and watery to thick and greenish.

Allergic conjunctivitis can be diagnosed by a veterinarian and is often treated with medicated eye drops.

Runny nose

A runny nose and sneezing can also be symptoms caused by environmental allergens. Clear discharge, rather than a thick green or yellow discharge, may be an indication that your pet’s runny nose is the result of an AD rather than a respiratory infection.

Treatment

Your veterinarian will often start your pet on medication to help control the itching, as well as medication to treat any current skin/ear infections. They may recommend additional testing to help determine the exact allergens causing your pet’s symptoms. Treatment to help control your pet’s symptoms will typically be lifelong. Sometimes, once you have a better idea of which allergens are triggering a reaction, you can try to minimize your pet’s exposure to them:

• The pollen count tends to rise during hot weather and is at its highest in the mornings and evenings, so try and keep windows and doors closed and avoid walking your dog at these times.
• Wiping them down (particularly their face and feet) with a damp cloth when they come inside can help remove allergens from their hair and skin.
• Grooming and clipping long hair helps remove pollen and other allergens from their coat, and using specially formulated shampoos can also help skin irritation.
• Regularly vacuuming with a HEPA-equipped vacuum and washing bedding can also help reduce allergens in the home.
• Your veterinarian may recommend allergy immunotherapy - a treatment which involves exposing your pet to small amounts of the allergen that are gradually increased over time so that your pet becomes less sensitive to the allergen.

Flea allergies are more common when the weather is warmer and flea numbers peak. Although, fleas can live year round in our temperature controlled homes. Flea bites can cause itching in many pets, however some pets may develop a sensitivity to the flea’s saliva, resulting in inflammation and extreme irritation. It is important that a flea allergy is diagnosed and the symptoms treated as soon as possible.

Symptoms

Signs of a flea allergy include severe itching and hair loss. The hind end (rump and tail head), head and neck are common areas affected. You will likely see your pet scratching and biting these areas in particular. Skin infections can also easily develop if the symptoms are left untreated.

Prevention

Having a regular flea prevention program in place is essential for pets that are sensitive to flea bites. Treating your pet’s environment is also important if you currently have a problem with fleas.

• Treat all pets in the household with flea prevention products all year round. There are a number of oral and topical medications available. However, for dog’s that enjoy playing in water it’s important to remember that many topical flea preventives are not water resistant. Speak to your veterinarian for advice on the best products to use.
• Fleas can survive without a host for many months, so washing bedding regularly and throwing away the dust bag after vacuuming will help to eliminate fleas from your home. If you have a severe flea infestation it is often best to work with a professional to treat your home and yard for fleas.

Insect bites and stings are common, particularly during the summer months. Reactions to bites and stings can vary from mild to severe, so it’s important to monitor your pet closely if you believe they may have been stung. Ideally, you should be able to identify the signs and recognize when it’s time to seek emergency treatment.

Symptoms

You pet is more likely to get stung around the face or paws, and the sting will tend to be accompanied by redness and localized swelling and itching.

In the case of an allergic reaction, your pet may experience major swelling, breathing difficulties, sickness and general weakness, and they will require emergency veterinary attention. If your pet has been stung on the neck or inside the mouth or throat, it’s important that you take them to your nearest veterinarian straight away.

Treatment

Mild stings

Bathing the sting in cold water or holding an ice pack against it for 15 minutes will help to reduce the swelling and itchiness, which will then help you to determine the cause of the sting.

• Ant bites often do not cause an allergic reaction, and the itchiness should subside after 10-15 minutes.
• If your pet was stung by a wasp, there may be multiple stings. Wasp stings are alkaline, and can be treated effectively at home with lemon juice or vinegar.
• If your pet was stung by a bee or a hornet, there will just be a single sting; however you will need to remove the stinger from the skin if you can by scraping straight across the skin with a sharp plastic edge. Attempting to squeeze the stinger may result in more venom being released into the skin. Bee and hornet stings are acidic, and so can be neutralized with a solution made from bicarbonate of soda and water.

In the case of a mild sting, the swelling should subside after a few days and you will just need to monitor your pet to ensure they don’t lick or bite the wound, which could potentially lead to infection. If the swelling does not go down, then consult your veterinarian for advice.

Severe reactions

If your pet’s symptoms do not improve and you believe they may be experiencing an allergic reaction, it’s important to seek advice from your veterinarian. They may prescribe antihistamines to help treat the symptoms, or in cases of anaphylaxis, which are extremely rare, your pet may require an epinephrine shot to control the swelling of the respiratory tract and enable them to breathe properly.

Diphenhydramine Hydrochloride, more commonly known by its trade name, Benadryl, is an effective antihistamine medication used to treat allergies in humans. But is it safe for your pet? Trupanion veterinarian, Dr. Sarah Nold offers advice on what Benadryl can be used for and whether it is suitable for treating your pet’s allergies.

• Benadryl is primarily used to treat the symptoms of AD and flea allergies, as well as insect bites and stings. However, it is also sometimes used in dogs to help prevent motion sickness.
• Benadryl should be used with caution, and only with your veterinarian’s approval if your pet has glaucoma, prostatic hypertrophy, hyperthyroidism, cardiovascular disease or hypertension (high blood pressure). It is also often not recommended for working animals as it can cause drowsiness.
• Benadryl may interfere with some types of testing, such as allergy testing. It may also interact with some types of pain relief medication, sedatives or behavior modifiers, so it is important to make your veterinarian aware of any other medication your pet is taking.
• Only the pure form of Diphenhydramine Hydrochloride is safe for your pet, so it is vital that you select a form of Benadryl that does not contain other medications for cold or sinus symptoms. Show the packaging to your veterinarian if you are unsure.
• Your veterinarian will be able to advise you on the appropriate dose and frequency for your pet’s weight, age, and health. While Benadryl can be safe and sometimes effective for treating allergies, always check with your veterinarian before using it or if you have any concerns.