What are allergies in dogs?
An allergy is a condition of hypersensitivity of the immune system to a certain substance called an allergen. Most allergens are proteins from plants, insects, animals or foods.
In allergies, the immune system’s response can be harmful to the dog’s body.
Exposure to an allergen, usually several times over a period of months or years, sensitizes the immune system, and subsequent exposure to the same or related allergen causes an overreaction. Normally, the immune system protects the dog from infection and disease, but with allergies, the immune system response can be really harmful to the body. Allergies can be seen as an unnecessary normal immune response to a benign foreign substance.
The immune responses associated with allergies are quite complex. Most reactions involve allergen protein molecules joining with antibodies in the blood and then attaching to a type of cell called mast cells. Mast cells are found in many tissues throughout the body. When the antigen and antibody react with the mast cells, the mast cells release potent chemicals such as histamines, which cause localized inflammation like redness, swelling and itching. This inflammation causes various signs associated with an allergic reaction.
Symptoms and signs of allergies in dogs
In the dog, the most common symptom associated with allergies is itchy skin, localized (in one area) or generalized (all over the body). In some cases, signs of allergies include respiratory disturbances with coughing, sneezing and/or wheezing. Sometimes there may be liquid discharge from the eyes or nose. In other cases, allergy symptoms affect the digestive system, leading to vomiting and diarrhea.
Symptoms of allergies in dogs:
- Itching
- Urticaria
- Swelling of the face, ears, lips, eyelids or ear pieces
- Red or inflamed skin
- Diarrhea
- Vomiting
- Sneezing
- Itchy ears
- Chronic ear infections
- Itchy eyes
- Constant licking
How common are allergies in dogs?
Unfortunately, allergies are quite common in dogs of all breeds and backgrounds. Most allergies appear after the pet is six months old, and most affected dogs are older than one or two years.
Can allergies be hereditary? Some allergies are considered hereditary. Inherited allergies are atopy (atopic dermatitis) or allergies to pollen and plants.
The most common allergens in dogs
A very large number of substances can act as allergens. Most are insect, plant or animal proteins, but small chemical molecules can also cause allergies. Examples of common allergens include pollen, mold spores, dust mites, skin cells (just like people are allergic to animals), insect proteins such as flea saliva, and some medications.
Types of allergies
What types of allergies are there? There are several ways to classify allergies. Some examples of these classifications include:
- Allergen – flea allergy, food allergy
- The route by which the allergen enters the body – inhalation allergy, skin contact allergy, or food allergy
- Time it takes for the immune system to respond – immediate-type hypersensitivity, also called anaphylaxis or shock, and delayed-type hypersensitivity
- Clinical signs – allergic dermatitis or allergic bronchitis
- Hereditary forms – atopic or seasonal allergies
What is an allergy to fleas (flea bites) or insects and how to treat it?
Insect bite allergy is an exaggerated inflammatory reaction to an insect bite. Arachnids such as spiders and mites, as well as insects including fleas, flies, flies, gadflies, mosquitoes, ants, bees, hornets and wasps can cause an allergic reaction in sensitive dogs.
Flea saliva is the most common insect allergen in dogs causing flea allergic dermatitis. Most dogs experience minor local irritation from flea bites. But a dog sensitive to flea bites will exhibit severe localized itching. A dog with flea allergic dermatitis will bite and scratch itself. She may thus lose a lot of hair, especially at the base of the tail. A secondary bacterial infection can develop in areas of damaged skin.
Since one flea can be a problem for a dog with flea dermatitis, strict flea control is necessary. This is difficult given the life cycle of fleas, but today’s monthly preventative measures and home treatment methods allow you to provide a flea-free environment for your dog. Your dog dermatologist can give you tips on protecting your dog and other pets from fleas. When strict flea control is not possible or in cases of severe itching, your veterinarian dermatologist may prescribe antihistamines or corticosteroids (steroids) to block the acute allergic reaction and give immediate relief. If a bacterial infection is present, the doctor will prescribe an appropriate antibiotic.
What is atopy or atopic dermatitis and how is it treated?
The term inhalation allergy in the dog is often used synonymously with atopy or atopic dermatitis. The main inhalation (airborne) allergens are tree pollen (cedar, ash, oak, etc.), grass pollen, weed pollen (ragweed), mold, and house dust mites. Many of these allergies are seasonal, such as ragweed, cedar, and grass pollen. Others, however, such as mold and house dust mites, occur year-round. When people inhale these allergens, the resulting allergies mostly manifest as upper respiratory symptoms: runny nose, runny nose and sneezing (hay fever). Although sometimes allergy symptoms include allergic rhinitis or bronchitis, most dogs with inhalation allergies present with itchy skin (pruritus). Because of these clinical signs, the condition is also called inhalation allergic dermatitis. The dog may rub his face, lick his feet, and scratch his armpits (underarms).
Most dogs with airborne allergies show their first signs between one and three years of age. Affected dogs often react to more than one allergen and often experience concurrent allergies to fleas or food. If the offending allergens can be identified by intradermal allergen testing (intradermal tests) or blood tests, the dog should be protected as much as possible from their exposure. Since most of these allergens are found in the environment, recurrent attacks are likely. Symptoms of atopy can be controlled, but a permanent cure is usually not possible.
Anti-inflammatory therapy
Treatment with anti-inflammatory drugs, such as corticosteroids or antihistamines, in most cases quickly blocks the allergic reaction. In some cases, adding fatty acids to the diet may improve the response to steroids and antihistamines. Recently approved drugs, such as oral cyclosporine, are also very helpful in treating atopy and have fewer long-term side effects than corticosteroids.
Shampoo therapy
Frequent bathing with a hypoallergenic shampoo can soothe itchy, inflamed skin. Bathing also washes away allergens in and on the coat that can penetrate the skin. Some therapeutic shampoos also contain anti-inflammatory ingredients that can benefit your dog.
What are food allergies and how are they treated?
Food allergy or food hypersensitivity in dogs can develop to almost any protein or carbohydrate component in food. It most often develops in response to proteins in the food. The foods most commonly associated with food allergies in dogs are dairy products, beef, wheat gluten, chicken, chicken eggs, lamb and soy. Food allergies can occur at almost any age, but are most common in dogs over one year of age. Food allergies can cause any of the previously discussed clinical signs, including itching, digestive upset, and respiratory distress. A dog can have several types of allergies at the same time, such as food allergies and atopy, which makes accurate diagnosis of the cause of itching in a dog quite difficult.
Food allergies usually do not respond well to corticosteroids or other treatments. Treatment requires identifying the disruptive component(s) of the diet and eliminating them. The most accurate way to test for food allergies is to try a hypoallergenic diet. Such a diet is also known as an elimination diet. Since it takes at least eight weeks to eliminate all other foods from the body, the dog must follow the special diet exclusively for eight to twelve weeks. If your dog responds positively to such testing and the clinical signs improve, your veterinarian dermatologist will advise you on how to proceed.
It should be emphasized that if the exclusion diet is not followed exactly as prescribed by your veterinarian dermatologist or nutritionist, it will not be a valid test. All foods other than those prescribed, as well as treats and flavored vitamins, must be discontinued for the duration of the diet. There may also be problems with certain types of chewable tablets or medications. Your veterinarian dermatologist will discuss the specific diet and any restrictions recommended for your dog.
Treatment and prevention of allergies in a dog
The best way to treat allergies in your dog is to find and eliminate the cause and the allergens. This may not always be possible. But, in terms of treatment, it depends on the type of allergy your dog has. For example, the best way to treat dermatitis from a flea allergy is to kill the fleas, while the best way to treat a food allergy or food intolerance is to change the diet.
In addition to any lifestyle and grooming changes that may be necessary, your veterinarian may also prescribe medication for your dog to help control the symptoms associated with the allergic reaction, such as itching and any secondary skin infections that may have developed as a result of the irritants.
It is important that when treating allergies in dogs, it is the veterinarian dermatologist who prescribes the medications and necessary treatment to avoid complications. For example, one such complication when treating allergies in dogs with hormones is demodicosis.
If your dog has a severe allergic reaction, it is best to see a veterinarian dermatologist as soon as possible. Allergy symptoms can be confused with other disorders or they can occur at the same time. One disorder with which allergies are confused is shingles (dermatophytosis). In some cases, this disease causes severe itching, which pet owners and some doctors mistakenly attribute to food allergies.
So don’t try to diagnose your dog without veterinary professional help. Be prepared to have your dog diagnosed to rule out other causes of itching and skin problems. If allergies are diagnosed, your entire family should follow the advice of your veterinarian dermatologist very carefully to successfully relieve your pet’s discomfort.
