Allergies in dogs: symptoms and treatment

One of the most common health problems in dogs is allergies. They can develop to almost anything. That's why it's so difficult to quickly identify the allergen. But what exactly are allergies in dogs, and how do they develop? Is there a classification system? What are the typical symptoms? And most importantly, how can you help your pet: what should you give your dog for allergies?

What is an allergy?

In scientific terms, an allergy is an increased and qualitatively altered reaction of the body to the entry of substances of an antigenic and non-antigenic nature, or immune reactions occurring in a sensitized (sensitization is increased and altered sensitivity) organism.

Simply put, it's the body's reaction to a substance that triggers an abnormal "response." This substance "shakes up" the animal's immune system, causing the body to try to fight it by producing antibodies (class E). Normally, these antibodies make up only 0.03% of the total—a very small amount. As soon as their numbers begin to increase, the immune system's sensitivity immediately becomes "distorted."

Allergies are most often observed in animals with a compromised immune system, as well as in those with an allergic constitution (increased permeability of blood vessels, skin, and tissues of the respiratory and digestive organs).

If a dog has an allergic constitution, the immune system's feedback loop is not triggered, meaning class E antibodies continue to be produced (even after their levels have reached normal levels). This "hypersensitivity" can be inherited and often develops later in life.

What can trigger the development of allergies in a perfectly healthy animal? Frequent vaccinations (a jolt to the immune system; don't give them more often than recommended). according to the vaccination schedule), use of expired medications, frequent contact with synthetic substances, etc.

By degree of sensitivity (propensity to allergies) in descending order: guinea pigs, rabbits, sheep, goats, cattle, horses, dogs, pigs, birds, monkeys, humans.

The mechanism of development of an allergic reaction

There are 3 stages in the development of allergies:

1. Stage of immune reactions
2. Stage of pathochemical changes
3. Stage of pathophysiological disorders

Stage of immune reactions

In response to allergens, a body with an altered immune system produces a huge number of class E antibodies and T-lymphocytes, which attach to the surface of cells and tissues. This makes these cells hypersensitive to repeated exposure to the allergen.

If a large number of antibodies and T-lymphocytes attach to tissues, they are called shock cells. They are the first to react to an allergen entering the body. Shock cells most often include blood vessel walls, smooth muscles, skin, and tissues of the respiratory and digestive organs.

All this happens during the body’s initial “acquaintance” with the allergen.

Stage of pathochemical changes

When allergens re-enter the body, they interact with class E antibodies and altered T-lymphocytes located on the cell surface. This interaction results in cell damage and destruction. As a result, a large number of active substances are produced—histamine, serotonin, and bragikinin.

Stage of immune reactions

The resulting biologically active substances enter the bloodstream, spread throughout the body, and cause dysfunction in organs or tissues. Most often, dysfunction is detected in the tissues that are in shock. Other tissues react to a lesser degree.

What can a dog develop an allergy to?

Substances that can alter the body's sensitivity (increase it) are called allergens. The most common are viruses, bacteria, fungi, helminths (and the toxins they secrete during their life cycle), and poisons.

There are also exogenous factors (coming from outside). These include:

• Medicines
• Substances of animal origin (fluff, wool, feathers)
• Foreign proteins (enzymes and hormones)
• Pollen of plants, some types of herbs and flowers (especially home ornamental ones)
• Insect and reptile poison. For flea bites, ticks, mosquitoes and other bloodsuckers, as well as their waste products
• Household chemicals
• Food (milk, berries, cereals, etc.).

But the rarest are "internal" (endogenous) allergens. They can also be called autoallergens. These are the body's own defective cells or tissues. There have been cases of animals developing allergies to the lens of the eye, thyroid tissue, testicles, and gray matter.

Classification

Allergic reactions have several classifications:

By the rate of occurrence

Immediate allergy – Allergy symptoms in dogs appear just 3-5 minutes after the allergen enters an already sensitized (hypersensitive) body. This means the animal has already been exposed to the allergen at least once.

Delayed allergy – in this case, the dog’s allergy symptoms appear within one to two or three days after the “irritant” enters the body.

By type of allergen

• Infectious – develops upon the entry of a pathogenic agent into the body. For example, the pathogen causing tuberculosis, brucellosis, leptospirosis and others.
• Serum-induced – occurs after the introduction of serum (prepared antibodies against a disease) into the body. For example, tetanus toxoid.
• Food - for any component of feed.
• Plant - on pollen or the plants themselves.
• Medicinal – for the component of the drug.
• Household – mold, dust, even food for other pets (fish, rodents).
• Autoallergy – to one’s own defective cells.
• Idiosyncrasy is a congenital hypersensitivity to certain foods.

By the nature of sensitization

Non-specific – when sensitivity is increased by exposure to one type of allergen, but the body will react to another. Even non-specific allergies in dogs can be divided into two subtypes:

1. Heteroallergy is when sensitization occurs due to a non-antigenic allergen, but a reaction occurs as soon as an antigenic allergen enters the body. In layman's terms, a cold is a non-antigenic factor, while an invading virus or bacteria is antigenic. Therefore, a cold weakens the immune system, cells and tissues become more sensitive, and invading pathogens trigger an allergic reaction.
2. Paraallergy – although one allergen causes sensitization and the immune system responds to another, both irritants are antigenic. For example, viral infections always weaken the immune system, and the invading bacteria become a "second" antigenic allergen.

Specific – a reaction to the same allergen. For a reaction to develop, the "irritant" must enter the body twice (the first exposure increases sensitivity, the second provokes the appearance of clinical symptoms).

Depending on the degree of violation

General – the functions of all organs and systems are impaired. Most often, it develops in response to food.

Local – a reaction at the injection site/direct contact. For example, after drug administration. Swelling, redness, puffiness, and even pus may appear. Often, multiple injections of the allergen are required.

Symptoms

Allergy manifests itself as a disruption of the functions of organs and systems.

From the circulatory system

Hemorrhages (including on the skin and visible mucous membranes), congestion, changes in blood pressure (both decrease and increase).

From the digestive system

The most frequently recorded allergy symptoms are vomiting, diarrhea, and changes in enzyme activity.

From the nervous system

Convulsions (involuntary muscle twitching) or, conversely, paralysis may occur.

From the side of thermoregulation and other systems

Body temperature changes, swelling appears, and joints swell. If the dog had chronic illnesses, they will worsen and begin to bother the pet again. Itching, scratching, sneezing, and twitching may occur, and, in very rare cases, involuntary urination and defecation may occur.

Now let's look at what symptoms are characteristic of different types of allergies in dogs.

Food allergy

Rash, redness on the skin, severe itching, hair loss. Visible on the skin dandruffThe tissues themselves are dry, but there are wet patches in the chest and armpits. Bowel movements change, and vomiting may begin. If you look into the mouth, you may notice inflammation of the gums (stomatitis), and the smell from the mouth changes. Allergy symptoms in dogs may disappear (or worsen) as soon as the diet is changed. There are dogs that have chicken allergy.

Flea allergy dermatitis (allergy to flea bites and their excrement)

Presence of bloodsuckers. If you don't see these little critters, you can shake the fur with a piece of white paper or comb it. You'll immediately notice black dots on the paper. Bite marks (pinpoint redness) and scratches are visible on the skin. Hair loss may occur (especially in areas of intense itching). Severe redness may also be present in the groin area.

Atopic dermatitis

Young dogs, aged between one and three years, are most often affected. Lesions appear on the face, armpits, ears, paws, and groin. Pets tend to lick the affected areas. Weeping areas may also be observed.

Autoimmune

Erythematous blisters appear on the skin. Cutaneous vasculitis, lupus, erythema multiforme. Epidermal necrolysis (tissue death) is also recorded.

Contact dermatitis

Redness and itching appear in areas where the skin came into contact with the allergen. If the animal is intolerant to household chemicals, symptoms of dermatitis will appear on the feet, paw pads, scrotum (in males), and abdomen. Eczema will develop between the toes.

Medicinal

It develops immediately after taking the medication. The main symptoms are clearly defined lesions, with almost all of the rash occurring on the face. The urticaria disappears as suddenly as it appears. The most dangerous symptom is anaphylaxis.

Allergic otitis

It presents like a typical middle ear infection: redness, itching, exudate, scratching, swelling, and increased temperature of the auricle. However, it can only be distinguished from a typical otitis media by a bacterial culture.

Infectious allergy

It exhibits symptoms similar to those of a disease. Viruses, bacteria, and fungi act not only as allergens but also as pathogens.

Treating a dog with allergies

Treatment for dogs with allergies must begin as soon as possible. Otherwise, anaphylactic shock (pharyngeal paralysis and possibly angioedema) may develop. Therefore, as soon as you notice allergy symptoms in your dog, contact your veterinarian immediately.

First, you can have your pet tested (the doctor will notice any characteristic abnormalities). Then, it's necessary to determine what triggered the change in sensitivity. Without eliminating the underlying cause, it will be impossible to cure your pet. Not only will the symptoms return, but the attacks will become increasingly severe and frightening.

Therefore, if a dog has reacted this way to food, a corresponding diet will need to be selected for the rest of its life. If it's allergic to fleas or bloodsuckers, its skin will need to be examined regularly to remove any parasites. Prevention (shampoos, collars, drops, and sprays) should be used, but these must be chosen carefully to avoid triggering a new attack. If it's allergic to plants, it's best to keep your pet as far away from flowering plants as possible, make your home safe, and always carry allergy pills with you when you go for walks.

What can I give my dog ​​for allergies? Antihistamines are used as emergency treatment: diphenhydramine, suprastin, pipolfen, calcium gluconate, and tavegil. The dosage should be calculated based on the pet's weight.

You can also ask our website's staff veterinarian a question, who will answer them as quickly as possible in the comments box below.

Read also:

• Dermatitis in dogs
• Apoquel for dogs
• Eczema in dogs