Pets and Allergies A-Z

Pet allergies 1

 

Allergies to pets (and not only): what triggers them?

Pet allergies 1

 

Allergies to pets (and not only): what triggers them?

Cats and dogs are the main culprits, but birds, ferrets and even… domestic iguanas also cause allergies. It’s all our immune system’s fault.

 

Damn allergy. Especially when spring has nothing to do with it. Here we are talking about that allergy that lasts forever because it depends on pets: cats, dogs, rabbits, but also horses or birds. But what happens when an allergy is triggered? That our body activates its antibodies, recognizing a series of harmless proteins as enemies. In practice, an allergy is an adverse reaction controlled by the immune system that… makes us sneeze.

ALLERGIES: WHY? An allergy – to a pollen, a drug, an insect bite – is therefore an honest mistake of our immune system, which sees a threat where there is instead a harmless molecule.

 

 

WHEN THE IMMUNE SYSTEM RESPONSE IS TRIGGED. “IgE antibodies are used to fight certain parasites, such as Schistosoma, which were once very widespread and have now practically disappeared in many parts of the world,” says Fiocchi. However, IgE has remained, and is extremely sensitive to a series of perfectly harmless proteins. IgE are molecules that bind to the surface of some cells of the immune system: when an antigen (a foreign molecule that our body recognizes as dangerous) “arrives” on the IgE, the immune response is triggered. Allergies, as Fiocchi adds, are therefore «functionally all the same thing: an incorrect reaction to something harmless, be it a cat or pollen.

 

DOGS, RODENTS AND HORSES. «The domestic species that cause the most problems are dogs, cats, small rodents and horses. We can also add an allergy that is typically professional, that to cattle», explains Fiocchi. «All these animals have in common a protein called serum albumin, which is found primarily in the blood, but can also end up in dead skin, saliva and sweat». Serum albumin is the most abundant protein in the blood of mammals and is the cause of a long list of allergies of all kinds: beef allergy, for example, which affects one in three hundred children and causes nausea, swollen lips, hives and abdominal pain, is caused by bovine serum albumin.

 

For example, the allergen Fel d 2 (from Felis domesticus) of the cat, which is found in skin “flakes”, urine and serum, the Can f 3 (from Canis familiaris) of the dog, which is found in saliva, skin flakes, serum, or Equ c 3 (from Equus caballus) of the horse, belong to the albumin family.

 

However, there are other proteins that contribute to allergic reactions (for example, from the lipocalin family): they are found in epidermal derivatives, urine, saliva. Various cat allergens are present in saliva, and given the feline habit of constantly licking itself, the incriminated proteins are distributed on the fur, where they remain attached: at that point, they can be collected by the human during a petting session or transported around by lost hair or flakes of dead skin that come off the animal’s body. «The allergy to dogs, cats, but also horses and rodents, therefore, is not an allergy to hair. It is an allergy carried on the hair, but which originates elsewhere», specifies Fiocchi. When the allergens are inhaled or end up in the eyes, for example, the reaction is triggered. And here comes sneezing, red eyes, itching, a blocked nose. BEWARE OF THE KITTEN. «The main allergen of cats is called Fel d 1. It is found in saliva and sebum, and therefore it is easy for the animal to spread it by licking itself», explains Chiara Noli, European Specialist in veterinary dermatology. «Only cats produce it and it is a small glycoprotein, then released into the environment through skin scales and hair. It can also stick to clothes and be carried around: high concentrations have also been found in school classrooms, where obviously there are no cats, but children with cats who bring allergens from home». Allergens can also reach places where cats have not set foot. “I happened to treat a patient who was suddenly struck by allergic asthma with no apparent explanation,” says Fiocchi. “In the end we discovered that her daughter had unknowingly adopted a kitten: she kept it locked in her room, but obviously carried the allergenic material around the house.”

 

BIRDS AND REPTILES. As mentioned, Fel d 1 is a feline exclusive, but dogs, horses and rodents also have their specific allergens, which are added to the risk of more generic allergens such as serum albumins. But we could also be allergic to other mammals that we had never considered.

The boom in “new” pets has already brought to light a wave of unexpected allergies: to ferrets, for example. Or to rabbits. And then there are the birds: in 2019, according to Censis, Italian homes hosted almost 13 million of them. Birds can be a source of allergies, caused by proteins contained in dead skin and feces. Even with reptiles, which are definitely not soft and furry, we could have problems. There is more than one study that has demonstrated IgE-mediated allergic reactions to iguana bites and simple proximity: a skin reaction test done on a man who had shown symptoms of allergic rhinitis showed that the patient reacted to an extract of scales from his pet iguana.

 

LIONS, FOXES AND REINDEER. But could we be allergic to a lion, a deer or some other wild animal? You may be surprised, but there are answers. For example, there are confirmed cases of reindeer allergies among farmers in Sweden, Finland and Norway (we’ll spare you the Santa Claus jokes). In the United States and Canada, there are several examples of hunters who have been found to be allergic to deer or moose. We are less certain about predators, for obvious reasons, but laboratory tests have provided some information.

 

PETS SUFFER FROM ALLERGIES TOO. If it’s any consolation, the problem of allergies to dogs, cats and other pets is not unique to us. “I’m a veterinary dermatologist and 80% of my work with dogs and cats has to do with allergies,” explains Noli. “Just like in people, it is estimated that 20-30% of animals are allergic. In most cases, the allergy presents itself in the form of atopic dermatitis, a condition that favors the onset of bacterial infections, and which manifests itself in the form of itching». And what are the allergens that cause atopic dermatitis? The same ones that create problems for us. «Most frequently, cats and dogs are allergic to dust mites (see below), but there can also be animals allergic to the epithelium of birds or horses, dogs allergic to cats and even cats allergic… to cats». There are also dogs and cats allergic to dead skin left around by their owners. We humans also cause allergies, after all…

 

Damn allergy. Especially when spring has nothing to do with it. Here we are talking about that allergy that lasts forever because it depends on pets: cats, dogs, rabbits, but also horses or birds. But what happens when an allergy is triggered? That our body activates its antibodies, recognizing a series of harmless proteins as enemies. In practice, an allergy is an adverse reaction controlled by the immune system that… makes us sneeze.

ALLERGIES: WHY? An allergy – to a pollen, a drug, an insect bite – is therefore an honest mistake of our immune system, which sees a threat where there is instead a harmless molecule.

 

 

WHEN THE IMMUNE SYSTEM RESPONSE IS TRIGGED. “IgE antibodies are used to fight certain parasites, such as Schistosoma, which were once very widespread and have now practically disappeared in many parts of the world,” says Fiocchi. However, IgE has remained, and is extremely sensitive to a series of perfectly harmless proteins. IgE are molecules that bind to the surface of some cells of the immune system: when an antigen (a foreign molecule that our body recognizes as dangerous) “arrives” on the IgE, the immune response is triggered. Allergies, as Fiocchi adds, are therefore «functionally all the same thing: an incorrect reaction to something harmless, be it a cat or pollen.

 

DOGS, RODENTS AND HORSES. «The domestic species that cause the most problems are dogs, cats, small rodents and horses. We can also add an allergy that is typically professional, that to cattle», explains Fiocchi. «All these animals have in common a protein called serum albumin, which is found primarily in the blood, but can also end up in dead skin, saliva and sweat». Serum albumin is the most abundant protein in the blood of mammals and is the cause of a long list of allergies of all kinds: beef allergy, for example, which affects one in three hundred children and causes nausea, swollen lips, hives and abdominal pain, is caused by bovine serum albumin.

 

For example, the allergen Fel d 2 (from Felis domesticus) of the cat, which is found in skin “flakes”, urine and serum, the Can f 3 (from Canis familiaris) of the dog, which is found in saliva, skin flakes, serum, or Equ c 3 (from Equus caballus) of the horse, belong to the albumin family.

 

However, there are other proteins that contribute to allergic reactions (for example, from the lipocalin family): they are found in epidermal derivatives, urine, saliva. Various cat allergens are present in saliva, and given the feline habit of constantly licking itself, the incriminated proteins are distributed on the fur, where they remain attached: at that point, they can be collected by the human during a petting session or transported around by lost hair or flakes of dead skin that come off the animal’s body. «The allergy to dogs, cats, but also horses and rodents, therefore, is not an allergy to hair. It is an allergy carried on the hair, but which originates elsewhere», specifies Fiocchi. When the allergens are inhaled or end up in the eyes, for example, the reaction is triggered. And here comes sneezing, red eyes, itching, a blocked nose. BEWARE OF THE KITTEN. «The main allergen of cats is called Fel d 1. It is found in saliva and sebum, and therefore it is easy for the animal to spread it by licking itself», explains Chiara Noli, European Specialist in veterinary dermatology. «Only cats produce it and it is a small glycoprotein, then released into the environment through skin scales and hair. It can also stick to clothes and be carried around: high concentrations have also been found in school classrooms, where obviously there are no cats, but children with cats who bring allergens from home». Allergens can also reach places where cats have not set foot. “I happened to treat a patient who was suddenly struck by allergic asthma with no apparent explanation,” says Fiocchi. “In the end we discovered that her daughter had unknowingly adopted a kitten: she kept it locked in her room, but obviously carried the allergenic material around the house.”

 

BIRDS AND REPTILES. As mentioned, Fel d 1 is a feline exclusive, but dogs, horses and rodents also have their specific allergens, which are added to the risk of more generic allergens such as serum albumins. But we could also be allergic to other mammals that we had never considered.

The boom in “new” pets has already brought to light a wave of unexpected allergies: to ferrets, for example. Or to rabbits. And then there are the birds: in 2019, according to Censis, Italian homes hosted almost 13 million of them. Birds can be a source of allergies, caused by proteins contained in dead skin and feces. Even with reptiles, which are definitely not soft and furry, we could have problems. There is more than one study that has demonstrated IgE-mediated allergic reactions to iguana bites and simple proximity: a skin reaction test done on a man who had shown symptoms of allergic rhinitis showed that the patient reacted to an extract of scales from his pet iguana.

 

LIONS, FOXES AND REINDEER. But could we be allergic to a lion, a deer or some other wild animal? You may be surprised, but there are answers. For example, there are confirmed cases of reindeer allergies among farmers in Sweden, Finland and Norway (we’ll spare you the Santa Claus jokes). In the United States and Canada, there are several examples of hunters who have been found to be allergic to deer or moose. We are less certain about predators, for obvious reasons, but laboratory tests have provided some information.

 

PETS SUFFER FROM ALLERGIES TOO. If it’s any consolation, the problem of allergies to dogs, cats and other pets is not unique to us. “I’m a veterinary dermatologist and 80% of my work with dogs and cats has to do with allergies,” explains Noli. “Just like in people, it is estimated that 20-30% of animals are allergic. In most cases, the allergy presents itself in the form of atopic dermatitis, a condition that favors the onset of bacterial infections, and which manifests itself in the form of itching». And what are the allergens that cause atopic dermatitis? The same ones that create problems for us. «Most frequently, cats and dogs are allergic to dust mites (see below), but there can also be animals allergic to the epithelium of birds or horses, dogs allergic to cats and even cats allergic… to cats». There are also dogs and cats allergic to dead skin left around by their owners. We humans also cause allergies, after all…