Animal allergy is defined as the development of allergic symptoms following contact with animals or the inhalation of small particles from animals. When these substances, called allergens, enter the body of an allergic individual, they cause a hypersensitivity reaction of the immune system by producing IgE antibodies that react with them, trigger the release of histamine and other chemicals, and produce inflammation of the nasal, ocular or bronchial mucosa, which will lead to the typical symptoms of the allergic reaction.

What animals can cause an allergy?

Any furry or feathered animal can cause an allergy in genetically susceptible individuals. Up to 366 species of animals have been described as being capable of causing allergic diseases in humans. Cats and dogs are the most common cause, as they are the most common pets, but allergy has been described for many other animals, such as horses, rabbits, guinea pigs, hamsters, rats, mice, gerbils, chinchillas, ferrets, squirrels, domestic birds, iguanas and other reptiles, etc.

What causes animal allergy?

Animal allergens are contained in the secretions of their sebaceous and salivary glands and in their feces, so the allergy occurs as a result of inhalation or contact with their dander, hair, urine, saliva or serum.

Is hair the cause of pet allergy?

Contrary to popular belief, it is not the hair that is the main cause of animal allergy, but the dander particles, which contain the allergens formed in the secretions of the sebaceous and salivary glands. In animals, as in humans, the skin gradually breaks down into microscopic scales as it is renewed. The allergen-containing secretions remain attached to the hair and the horny layer of the skin. As they break off, they create small particles that can remain airborne for a long time and, when inhaled, cause allergic symptoms in the nose, eyes and airways. These particles fall slowly and settle on the floor or furniture, but with small movements they become airborne again. This is why patients with pet allergies notice symptoms as soon as they enter homes or places where pets are present, even if they are not present at the time. Hair can also cause allergies, but less frequently because it is deposited on the floor and does not remain in the environment. You can still use a HEPA-type air purifier to minimize the presence of these allergens.

Can hairless animals also cause allergies?

Furry animals are the most common cause of allergy, but allergies to bird feathers and reptile scales have also been described.

There are isolated cases of rhinitis and asthma caused by bird feathers or by the use of feather comforters and pillows. In some cases, the allergy has been proven to be caused by mites that parasitize the feathers.

Why are pet allergies becoming more common?

The reasons why pet allergy has increased over the past few decades are not fully understood. In part, it is related to the current lifestyle in developed countries, where more and more people have pets and spend more time indoors, and where homes are less well ventilated and have carpets, rugs, and objects that act as reservoirs for these allergens, so that exposure to allergens is much greater and more prolonged in a population that is more likely to suffer from allergic diseases.

Hereditary factors may contribute to a predisposition to pet allergy. If there is a family history of allergy, especially in both parents, the risk of developing allergy in the child is high; and if one parent is allergic to an animal, the risk of the child developing allergy to animals is higher.

In addition, people who live with pets are not only exposed to the pet itself, but to many other allergenic or allergy-related substances, such as dust mites, fungi, and various other particles that can contaminate the environment.

What is the impact of animal allergic diseases on the quality of life of patients?

Allergic diseases in general have a significant impact on the quality of life of patients, which can be reduced by up to 70-80% compared to the general population, due to sleep disturbances, irritability, lack of concentration, limitation of physical effort, deterioration of school and work performance, need for treatment, attendance at medical consultations or emergency services, etc.

Is keeping animals a risk factor for rhinitis and asthma?

It is clearly established that the development of sensitization and allergic symptoms is related to allergen exposure. The higher the concentration of animal allergens in the home, the greater the likelihood that allergic individuals will develop asthmatic symptoms and that these symptoms will be severe. In the case of cats, the likelihood of suffering from asthma if people are sensitized to this animal is 4 to 6 times higher than in non-allergic people.

Can you be allergic to animals even if they are not kept in your home?

Yes, you can be allergic to animals even if you have never lived with them before.

Animal allergens are very ubiquitous and are carried in tiny particles, some of which are less than 5 microns, that remain airborne for long periods of time and are very easily dispersed in the environment. In addition, they are carried attached to people's clothing and hair, so they accumulate in places such as schools, transportation and public buildings, or even in homes where there are no pets, reaching concentrations high enough to cause sensitization and respiratory symptoms in allergic individuals. The concentration of these allergens depends on the number of pet owners in the area.

Can one have symptoms without touching or seeing the animal?

Animal dander remains airborne for a long time before settling. Therefore, when a person with a pet allergy goes into a home where there are animals, even if they are not present at the time, they may inhale these particles and experience symptoms.

Is it possible to be allergic to some breeds of animals and not others?

Sometimes, some allergic patients have symptoms to certain breeds of cats or dogs, while tolerating exposure to others.

Studies have shown no difference in the allergens produced by different breeds of dogs, cats or horses, and there are no breed-specific allergens. It is known that some breeds have a higher sebaceous secretion and excrete more dander than others, which causes more symptoms; and some animals have shorter hair. But it is important to remember that the main cause of allergy to animals is the dander they shed when their skin is renewed, whether they have a lot of hair or not.

What are the symptoms of pet allergy?

People with pet allergy, when breathing in animal particles, may experience the same symptoms as with other environmental allergens, namely rhinitis, conjunctivitis and asthma, which manifest as itchy nose or eyes, sneezing, nasal congestion, mucus discharge, watery eyes, coughing, shortness of breath and wheezing. In addition, contact with hair, dander and saliva causes itching, hives or swelling at the area of skin contact or on the eyelids. If you are allergic to saliva, you may experience symptoms when a person is licked by the animal or if you touch the animal after it has been licked. Some severe allergic reactions of anaphylaxis have been described following bites from hamsters, rats, gerbils, and other rodents, or by wounds or pricks from needles and lancets contaminated with animal products. In these cases, the allergen in the saliva can enter the bloodstream and trigger a generalized allergic reaction that can be life-threatening.

In people who are allergic to an animal they live with, daily contact causes progressive inflammation of the airways leading to symptoms, which may appear and disappear intermittently without being clearly linked to the animal. In addition, this inflammation makes the bronchial tubes more sensitive and reactive to other stimuli, such as exercise, cold air, dust, smoke and pollution, which would not cause symptoms if the bronchial tubes were not previously inflamed due to the animal allergy.

How is pet allergy treated?

The ideal treatment for a pet allergy patient is to remove the pet from the home and avoid contact with it.

Removing the pet sounds simple, but it is often not so simple because of the bond between the pet and its owner, especially in the case of cats, or the inability to find a new home or place to leave the pet. It is even more difficult to completely avoid contact with animals because of indirect exposure to them when visiting homes or places where animals are present, or simply by having contact with people who live with them.

What can be done if the animal is not removed from the home?

If you decide not to remove your pet, a series of measures can be advised to reduce the amount of allergens produced by the pet and their concentration in the environment:

You should avoid touching the pet and try to wash your hands after doing so.

Don't let them into the bedroom, let alone sleep there.

Pet beds and pillows should be cleaned regularly and placed in a separate area.

The house should be ventilated often, and air purification systems containing high efficiency HEPA filters can be used.

Thoroughly clean the home with HEPA-filtered vacuums, especially mattresses, pillows, upholstery and drapes, where animal allergens are most likely to settle.

Dogs and cats should be bathed at least once a week to reduce the amount of allergens accumulated in the dander, although this will only slightly reduce environmental allergen levels.

Wash clothes that have been in contact with the animals.

Scrub the pet regularly, 2 to 4 times a week, with a damp towel.

There are non-toxic lotions on the market that, when applied once a week to the pet's coat, moisturize it and prevent it from shedding as much dandruff, as they encapsulate the dandruff allergens and reduce their concentration to about 15-20%. Before the first application, it is advisable to brush or comb the animal thoroughly, in order to remove as much loose hair as possible. Next, moisten a cloth with the topical lotion and rub it carefully into the animal's skin. The application should be done in the direction of the hair and then in the opposite direction.

In any case, all of these measures taken together have not been proven to be completely effective and do not replace the opportunity to remove the pet from the home.