Dog allergy: causes and symptoms

An allergy is an excessive and inappropriate reaction by the immune system to a normally harmless substance. Thinking the body is in danger, it sets up a defence strategy and releases antibodies and the histamines responsible for allergic reactions which include skin reactions, breathing difficulties, swollen eyes, etc.

An allergy to dogs is in fact a reaction to allergens carried by dogs. These may be molecules contained in their saliva, urine or skin. These molecules generally enter the body via the respiratory tract.

There may be multiple exposures to these allergens before the allergy develops. This is known as the "sensitisation" phase and can last for months or even years.

During this period, certain allergen molecules are stored by the body so that the immune system can prepare its defences. When an allergy occurs, the mast cells responsible for protecting the body release histamine, which reacts to the perceived threat with a localised inflammatory response which varies in severity.

Dog hair is not allergenic per se. But when a dog licks itself, it 'allergens' its hair, i.e. it deposits allergens on its coat.

On a daily basis, dogs walk around and deposit hair all over our homes. These hairs quickly fill our various living areas, our furnishings, from carpets to curtains, our sheets and our clothes, increasing the risk of exposure.

It is not dog hair that is allergenic, but the molecules it carries. These allergenic molecules are the main causes of allergy to dogs and most often come from proteins present in:

• The animal's saliva

• Urine

• Dander, small flakes of dead skin

• Secretions from the sebaceous glands, which produce sebum at the base of the coat

• Secretions from the anal glands, which contain pheromones.

A dog's coat can also carry environmental allergens such as pollen, dust mites and mould, exposing us to them through physical contact, for example.

1. Identify the symptoms. Consult the list of common dog allergy symptoms and see if they apply to you. How do you react when you find yourself in the presence of a dog? There are certain signs that can tip you off: sneezing, watery eyes, itchy throat, etc.

2. Do an allergy test. An allergist can carry out an allergy test to check whether you are allergic to dogs. This usually involves a general questionnaire about your symptoms and living environment, skin tests and sometimes blood tests.

3. Try desensitisation. If an allergy is confirmed by your doctor, you can try a desensitisation programme. This involves gradually exposing the body to allergenic molecules so that it becomes accustomed to them. This is a long-term treatment, generally lasting several years.

Breathing difficulties

An allergic reaction to dogs generally manifests itself in the respiratory tract and resembles allergic rhinitis. We then notice:

• Sneezing

• Nasal congestion

• Nasal discharge

• An itching sensation on the roof of the mouth or throat

Eye reactions

These symptoms are often accompanied by disorders of the eye, similar to conjunctivitis:

• Watery eyes

• Itchy eyes

• Redness of the eye or eyelid

Skin reactions and dermatitis

Physical contact with a dog can also cause an allergic skin reaction. The allergic person may then observe the following on their skin:

• Red, dry patches (eczema)

• Hives

• An itching or burning sensation

Whatever the nature of the symptoms, they generally appear within minutes of exposure to the animal.

In rare cases, the symptoms of a dog allergy can become more severe. In these cases, you need to be particularly vigilant and see whether the symptoms involve:

• Breathing difficulties: wheezing, coughing, asthma attack

• Angioedema: swelling of the face or airways

• Anaphylactic shock: paleness, malaise, difficulty swallowing saliva, etc.

In this case, it is essential to call the emergency services immediately.

Children and babies

If you suspect a child or baby is having an allergic reaction, call the emergency services immediately.

1. Avoid contact with this dog. That's your top priority! Any physical contact between the animal and the allergic person must be avoided. The allergic person should not remain in the area where the dog lives.

2. Take a supplementary treatment. Depending on the case, this may involve antihistamines, corticoids, decongestants, nasal drops or eye drops, all of which can be prescribed by a doctor.

3. Follow an in-depth treatment. In other words, desensitisation. It takes time, but it is the only alternative available today for treating the root of the problem.

Allergy desensitisation is also known as "allergen immunotherapy". The aim is to reduce sensitivity to an allergen by gradually but regularly exposing the body to small quantities of that allergen.

The stages of desensitisation.

1. Consult an allergist. An appointment with an allergist allows you to assess the nature of your allergic reactions and your state of health. In order to make a diagnosis, he or she will ask you a series of questions about your reactions, the triggers, your living environment, etc.

2. Allergy tests. Secondly, if the doctor suspects an allergy, he or she will carry out blood and skin tests. These tests are used to confirm a diagnosis and determine which dog allergens you are sensitive to.

3. Treatment strategy. The test results will enable the doctor to determine a personalised support and desensitisation strategy.

4. Immunotherapy. Immunotherapy can vary in terms of how long it takes, depending on the allergens and the individual. It can last from several months to several years. During this period, the doctor may give you regular doses of dog allergens, in the form of injections or sublingual drops. The doses are gradually increased until the body develops a tolerance.

5. Maintenance period. Once the allergist has found an effective maintenance dose, you will continue to receive regular doses to maintain your tolerance to dog allergens.

Numerous studies have shown that keeping a pet can have a number of health benefits for children. In fact, close contact with a cat or dog from childhood can strengthen the child's immune system, reducing the risk of developing asthma or allergies, for example.

My advice: adopt one of these adorable little furry creatures!

Marie-Adine is a naturopath and a graduate of the Institut de Naturopathie Humaniste. For several years now, she has been helping her clients to be proactive about their own health by creating personalised, educational programmes. Passionate about our emotions and their impact on our ability to heal, she teaches a range of health techniques to help us manage stress, improve sleep, and boost vitality.